Foretravel Motorhome Forums => Foretravel Tech Talk => Topic started by: wayne m on July 02, 2012, 02:24:13 pm
Title: bulkhead blues
Post by: wayne m on July 02, 2012, 02:24:13 pm
I have been visually inspecting my bulkheads for several years, and have not seen any sign of failure. I have not put a torque wrench on any of the bolts. I have decided that this fall, while passing through nac I will have an expert deal with this nagging, impending doom type of worry.
my question is: if some of the bolts are broken, is it better to replace with larger diameter roll locks or to put in through bolts with nuts? grade 8 bolts with nuts would seem to me to be more of a permanent fix, but I would like to know what others have done? would you recommend the factory, extreme or m.o.t. for this surgery.
Title: Re: bulkhead blues
Post by: wolfe10 on July 02, 2012, 02:54:03 pm
Wayne,
I think a lot of the "bulkhead issue" has been blown well out of proportion.
Bulkheads do not just up and "fail". They fail one bolt at a time which puts more stress on the bolts on either side of the failed one. Sure, if neglected long enough that 5-8 bolts in a row fail, you can have a bulkhead issue. More related to owner neglect than a "doom and gloom" failure.
The method I like better is to either:
1. Remove the broken bolt (usually penetrating oil and then double nutting makes removal from the inside (access hole in bottom/coach underbelly), over-drill and thru-bolt with 3/8" grade 8 bolts with large washer on box beam side (as I outlined in the bulkhead article).
2. "Sister" the broken bolt. In other words drill and through bolt on either side of the broken bolt.
My suggestion is to not fret over it, but to use safety stands and take an inch/pound torque wrench and 15 minutes of your time to VERIFY the status of the bolts as well as to look for possible separation or evidence or rust in the two bulkhead areas.
If considered as a part of your annual maintenance, it takes very little time or dollars to keep your coach bulkheads in good condition.
Brett
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 02, 2012, 03:34:16 pm
I have been visually inspecting my bulkheads for several years, and have not seen any sign of failure. I have not put a torque wrench on any of the bolts. I have decided that this fall, while passing through nac I will have an expert deal with this nagging, impending doom type of worry.
my question is: if some of the bolts are broken, is it better to replace with larger diameter roll locks or to put in through bolts with nuts? grade 8 bolts with nuts would seem to me to be more of a permanent fix, but I would like to know what others have done? would you recommend the factory, extreme or m.o.t. for this surgery.
I never liked the factory method of attachment for the bulkheads. I contacted Linadapter for their advise. They use the blind bolts on skyscrapers to underwater installations. I bought a set of HB Hollo-Bolts at Lindapter - USA and Canada (http://www.lindapterusa.com/) in the optional galvanized finish @$9/each. There site has a lot of engineering PDFs and videos on how the Hollo-Bolts work. My pit will be ready for the weight of the U300 in a week so will post photos of my installation. Here is the page for the size I bought along with videos, prices for zinc, galvanized and stainless: 1/2" Box Bolt Size 1 - Box Bolt? / Hollo-Bolt® - Connectors - Simplified (http://www.simplifiedbuilding.com/store/connectors/boxbolt/1-2-box-bolt-size-1.html) The center bolt is 1/2" but the total size is quite a bit larger. A couple of box ends and a torque wrench are all that is needed to install (after the hole is drilled).
Slide show at: Box Bolt - Expansion Bolt for Structural Steel Tube - Steelwork, Cavity Fixing (http://www.simplifiedbuilding.com/solutions/boxbolt/)
Pierce
Title: Re: bulkhead blues
Post by: Peter & Beth on July 02, 2012, 03:36:12 pm
As I do not have the tools, skill nor the competency to perform this job I had Xtreme re-do the front & rear bulkheads in my 97 U270 this past June. You having a 98 coach should also have this type of inspection & repair done by professionals like Brett W. ;D , or MOT, FOT or Xtreme. BTW Xtreme will do either Grade 8 or SS through bolts/nuts/washers. Peter
Title: Re: bulkhead blues
Post by: Gary Bouland (RIP) on July 02, 2012, 05:03:40 pm
Pierce, That looks like a good solution that any of us could use. Question, Does install require drilling a larger size hole than is already in the bottom member ? Does the thickness of the materials to be attached matter ? Please let us know how process works. I would much rather do this than drill or cut holes in the fibreglas and than have to reseal them. Gary B Pierce, On Edit I read the brochure and see that a 13/16 hole is required. Gary B
Title: Re: bulkhead blues
Post by: wayne m on July 02, 2012, 05:20:34 pm
I believe that whoever said "it's not a question of if, it's a question of when" was correct regarding bulkhead failure. I have seen plenty of coaches with the plugs in the underbody, which I think indicates that they have been through bolted. the failure rate may very well be overblown.
It would be nice to know how many coaches have been treated prior to having a problem vs. how many coaches have had problems and also those that haven't been treated and have no signs of problems. perhaps someone with more computer savvy than me could start a poll that would shed more light on the issue.
Title: Re: bulkhead blues
Post by: Dave Head on July 02, 2012, 05:28:16 pm
13/16" hole size for the 1/2" bolt is getting pretty large.
Title: Re: bulkhead blues
Post by: John Haygarth on July 02, 2012, 05:36:21 pm
I like the idea of the bolts you are using Pierce but question the strength of using just one wall (cross section) of the sq tubing that I believe is used behind angle iron. The combined box section of the sq tube is stronger going all the way thru it and using a plate that is the same size (or bigger) as a backing, in my opinion would be much stronger than just using one wall thickness to hold on to!! It all depends on the thickness of the box wall as to how much strength and "holding capacity" that sq tube has. The bolts are fine but if there is not much to hold onto they will just "rip out" Having said this I am only going by what I presume the build up of the framing is like. I would be interested in seeing a cross section of the make up of that area if anyone has a drwg or knows what it is like and can post a sketch. John H
Title: Re: bulkhead blues
Post by: Gary Bouland (RIP) on July 02, 2012, 05:37:21 pm
Dave H, That is why I was asking, that is a very large hole for this area. I believe that Brett W recommends a 3/8 bolt which would be about 1/2 the size of this bolt. Gary B
Title: Re: bulkhead blues
Post by: Dave Head on July 02, 2012, 06:00:12 pm
I also seem to remember that the square stock is light duty - say conduit type grade? Wasn't the torque spec in inch pounds? Even the 5/16" assembly calls for 18 ft-lbs which could crush the square stock.
I think the concept is cool! It may be heavier duty than called for. The question is what happes if you don't meet the torque spec - would it back off?
Title: Re: bulkhead blues
Post by: P. Wyatt Sabourin on July 02, 2012, 06:47:37 pm
Rolok Torque values for their 5/16 18 tpi bolt with a 0.290 hole are 10 ftlb to drive (make threads), 21 ftlb to tighten, 45+ ftlb before failure, 15 ftlb to loosen.
Wayne I will bring my Jet 250 inch pound torque wrench to Qualicom Bay in July and you can check your bulk head bolts then.
Title: Re: bulkhead blues
Post by: Don & Tys on July 02, 2012, 07:04:40 pm
John et. al. I don't have time at the moment for a long post, but since I have some experience with this issue, I feel obliged to respond with my thoughts and some first hand knowledge about the bulkhead design.
When I first encountered the issue on our coach, I felt like the joint was under engineered and that the Roloks were like a glorified sheet metal screw merely designed to make assembly easier and quicker. Although I still feel that the joint is somewhat under engineered, the Roloks grip both vertical walls of the tubing because they cut their own threads while being installed (or rather roll their own threads... an important distinction which you can read about if you do a search on rolled threads). Since the threads are simultaneously engaged in both walls at the same time, there is no crushing force brought to bear on the tubing. Since this bulkhead joint tube is an eighth inch thick, both walls of the tube add up to 1/4" worth of thread bearing surface. According to ARP (American Racing Products) product info which you can easily find online, increasing the thread contact area more than the diameter of the bolt has very little effect on the strength of the joint, so the method used by Foretravel is a theoretically sound one given the number of fasteners involved (17) in our coach) in the joint. Also, the Roloks are very high strength fasteners (140,000PSI if memory serves me).
That said, I believe that through bolting with appropriate 3/8" bolts (In my case, I chose ARP 170,000PSI Stainless steel fasteners) and the fact that my entire tubing assembly in contact with the bulkhead joint is doubled up with 1/8" square tubing mostly backed up by 3/16" angle iron and secured with weld nuts for future removal if necessary, should preclude any future need to be concerned with the joint. I am attaching a picture of my coach after some of the rusty metal has been removed. I have posted many other pictures of the area in question, both before and after my repairs. This shot is taken from the street side with the right side being towards the rear of the coach. You can see the opening for the sewer hose compartment in the lower right side of the picture. The square tubing that bolts to the bulkhead is one continuous 1/8' thick walled piece of square tubing. Most all of the rest of the tubing is only 16 gauge.
The reason I still feel that this joint is still a bit under engineered is that this joint represents the transition from the traditional heavy framing that carries the engine and trans assembly, as well as the suspension (at least in coaches up to and including my year and possibly a few years newer), I feel that there should have been some more steel connecting engine side of the bulkhead and a few more gussets to take the load from the rear locating arms which pushes and pulls on the bulkhead joint with quite a bit of leverage in the area where the shackles are welded to the 1/4" angle iron. That said, I do feel like the Roloks are up to the task when they are protected from moisture and corrosive elements.
I like the idea of the bolts you are using Pierce but question the strength of using just one wall (cross section) of the sq tubing that I believe is used behind angle iron. The combined box section of the sq tube is stronger going all the way thru it and using a plate that is the same size (or bigger) as a backing, in my opinion would be much stronger than just using one wall thickness to hold on to!! It all depends on the thickness of the box wall as to how much strength and "holding capacity" that sq tube has. The bolts are fine but if there is not much to hold onto they will just "rip out" Having said this I am only going by what I presume the build up of the framing is like. I would be interested in seeing a cross section of the make up of that area if anyone has a drwg or knows what it is like and can post a sketch. John H
Title: Re: bulkhead blues
Post by: Caflashbob on July 02, 2012, 09:39:33 pm
So the engineering was ok. Just not sealing the area for corrosion.
I told Triana in oct 87 I did not like the fasteners but he swore they were fine. They were. Just not the installation.
If and when I get to Nac I will remind him of that original unihome tour I was given as the california sales manager along with my brother managers and my comment. I absolutely think he would remember. I remember the room like yesterday. Cursed with a good memory. I tried.
Bob
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 02, 2012, 10:49:57 pm
I always thought that good engineering/design had to take into account the operating environment of the vehicle including but not limited to moisture and chemical exposure, temperature, stress, vibration and design lifespan and should not be limited to a single item but all components of that assembly.
If these failures/separations had happened in an aircraft, the FAA would have immediately issued an air worthiness directive (AD note), required the manufacture to come up with a fix and notified all owners. Guess a bunch of retirees rolling down the road don't rate.
Not all Foretravel owners should be expected to have the mechanical expertise to determine if they are suffering any bulkhead deterioration and can't be faulted for not being able to crawl underneath and inspect it. Age with accompanying stiffness has limited many of us to the role of an armchair mechanic. Without my new pit, I have been very limited to the time I could spend under the beast. Owners may however, want to have a knowledgeable person occasionally check this area visually and with a torque wrench, perhaps when the chassis is greased or the brake pads checked. This is particularly important for coaches operating in northern states with salt used on the roads.
In a couple of weeks, I will post photos of my modification with borescope shots of the tube interior condition and what the installation looks like from inside.
Pierce
Title: Re: bulkhead blues
Post by: Barry & Cindy on July 02, 2012, 11:14:52 pm
There is a 1-1/2" square tube running side to side inside the rear of the bay floor. But what is not being mentioned is that there is a second (or third) 1-1/2" square tube against part of the length of the main side-to-side square tube.
Using a 3-1/2" or longer bolt to fasten the rear angle iron to both of the square tubes offers a secure repair.
Cutting backing plates from 1-1/2" steel flat metal will force the bolt & nut to put compression on the edges of the square tubing which helps reduce crushing the tube.
RoIocks with our bay floor design are KNOWN to fail over time. Using any other blind fastener will not work either. The problem is the tube in the floor is too weak to start with, and further weakens from rust as coach gets older.
In some situations, the rear tube is also know to break loose from the rest of the inner floor structure, so even bolts & nuts will not work when that happens.
New Foretravels have a better design in their inner floor structure and use blind fastener HuckBolts. I heard that Foretravel is now repairing older coach's bulkhead problems with HuckBolts, which I think is not a good choice because all blind fasteners can pull out of rusted, weakened inner-floor tubing. Foretravel has also used new Rolock bolts to repair bulkheads. I think some solutions are designed to pacify owners, speed up repair time and satisfy attorneys, rather than be the best in the long run. For a while we heard that bulkhead problems were caused by owners.
I have seen repairs that cut through the bottom of the floor to the rear of the rearmost 1-1/2" square tube and use 2" bolts & nuts to hold things together. This method cuts through a second square tube and removes the support the second tube offers.
Also some use stainless steel bolts, which will not rust, but are not as strong as grade 8 bolts. Stainless may be better though, as a rusted grade-8 will weaken over time.
There are many different solutions to bulkhead problems and many opinions offered by coach owners. And professional's solutions seems to change from time to time.
It does not help that fresh water tank overflows onto bulkhead, insuring it gets wet. Bulkhead repairs should also include strengthening the vertical steel braces, like was included in later designs.
Title: Re: bulkhead blues
Post by: travelite on July 02, 2012, 11:50:14 pm
Although I still feel that the joint is somewhat under engineered, the Roloks grip both vertical walls of the tubing because they cut their own threads while being installed (or rather roll their own threads... an important distinction which you can read about if you do a search on rolled threads). Since the threads are simultaneously engaged in both walls at the same time, there is no crushing force brought to bear on the tubing. Since this bulkhead joint tube is an eighth inch thick, both walls of the tube add up to 1/4" worth of thread bearing surface. According to ARP (American Racing Products) product info which you can easily find online, increasing the thread contact area more than the diameter of the bolt has very little effect on the strength of the joint, so the method used by Foretravel is a theoretically sound one given the number of fasteners involved (17) in our coach) in the joint. Also, the Roloks are very high strength fasteners (140,000PSI if memory serves me).
Barry's post in this thread: My bulkhead experience (http://www.foreforums.com/index.php?topic=10668.msg55323#msg55323), indicates that the hole in the angle iron should be of a slightly larger bore so that the rolok bolt passes freely through the angle iron allowing the rolok to clamp the two members together. Step 4 (d).
Page 4 of the "Rolok, Thread Rolling Engineering Standards" document: http://www.semblex.com/files/Rolok-Semblex.pdf (http://www.semblex.com/files/Rolok-Semblex.pdf), specifies an optimum "nut material" thickness for the 5/16-18 Rolok of 5/16ths of an inch - this would be the optimal wall thickness of the square tubing which the angle iron is being clamped to. 5/16th inch thick material is required to achieve 4 full threads of engagement, or approximately the diameter of the bolt. To me this raises some questions over how the fastener was used in this application.
David Brady, NC
Title: Re: bulkhead blues
Post by: John Haygarth on July 03, 2012, 12:04:14 am
In Barrie's comments he mentions (as has been done many times before) that overflow from the water tank migrates into this joint area and promotes (along with other things) rusting and weakening of this assembly. This too me is an issue that can easily be prevented by not filling the tank to overflow. I have never allowed the tank to be more than 3/4 full and unless you have a faulty sensor find this a simple thing to do, and it keeps weight down and mpg up. I do not see a reason to have it that full as water is available in many places if needed. I agree that moving the location of overflow line away from the Bulkhead is a must, but after looking at mine I decided the easiest way to protect that area was to just put a simple deflector at the exit so no water actually flows onto it and also seal the joint with bitumin which I did when I first learnt of this possible problem. I gather I am lucky that I have not seen any hint of a rust jacking problem, even though we have gone thru' some really wet and snowy conditions on our trips south. John H
Title: Re: bulkhead blues
Post by: Benjie Zeller on July 03, 2012, 12:04:44 am
Curious, did they do sister bolts or replace the existing Roloks?
As I do not have the tools, skill nor the competency to perform this job I had Xtreme re-do the front & rear bulkheads in my 97 U270 this past June. You having a 98 coach should also have this type of inspection & repair done by professionals like Brett W. ;D , or MOT, FOT or Xtreme. BTW Xtreme will do either Grade 8 or SS through bolts/nuts/washers. Peter
Title: Re: bulkhead blues
Post by: Don & Tys on July 03, 2012, 12:59:51 am
Barry, You can see in the picture I posted where the second 1.5" square tubing was before I cut it out. This material was only 16 gage, or about 1/16" thick. It is not sturctural in nature, but is there where to make the utility compartment framing fit different floor plans (my conjecture). This 16 gage material was very rusty because of fresh water leaks, perhaps caused by something as simple as a $0.25 hose washer... I cut it out and welded in 11 gage tubing in its place and extended it all the way accross, as well as adding diagonal braces. The rusted out area was where plywood was inserted between the frame members, probably to provide support for hose reels and such. This plywood was completely decimated and turned into soup which in turn held moisture against the metal causing it to fail.
Regarding the vertical supports you mention for the engine side of the bulkhead... when I am done with the re-skinning and I close the gap for the last time, I am welding some 3"X5"X3/16" rectangular tubing to the vertical angle iron bulkhead supports which go on either side of the two horizontal suspension/powertrain back bones with added 1/4" gussets between same. This will support the push/pull of the drive train and suspension so that the bulkhead is not the (nearly) sole support for the rear axle location. Attached is a mockup made out of the two supports and some triangular gussets. There will be two of these just inside of where the shackles meet the suspension. I believe this will offer adequate backing for the bulkhead joint, at least more than what it came with...
Edit for added content: Regarding the Stainless Steel fastener option; if you are talking about the typical 18-8 stainless, then you are correct. They are roughly equavalent to grade 2 bolts. But there are options that are much stronger. The ones I chose from ARP ARP 623-4000 - ARP Stainless Steel Bolts - Overview - SummitRacing.com (http://www.summitracing.com/parts/ARP-623-4000/) are stronger than grade 8 bolts and will not rust. Don
There is a 1-1/2" square tube running side to side inside the rear of the bay floor. But what is not being mentioned is that there is a second (or third) 1-1/2" square tube against part of the length of the main side-to-side square tube.
Using a 3-1/2" or longer bolt to fasten the rear angle iron to both of the square tubes offers a secure repair.
Cutting backing plates from 1-1/2" steel flat metal will force the bolt & nut to put compression on the edges of the square tubing which helps reduce crushing the tube.
RoIocks with our bay floor design are KNOWN to fail over time. Using any other blind fastener will not work either. The problem is the tube in the floor is too weak to start with, and further weakens from rust as coach gets older.
In some situations, the rear tube is also know to break loose from the rest of the inner floor structure, so even bolts & nuts will not work when that happens.
New Foretravels have a better design in their inner floor structure and use blind fastener HuckBolts. I heard that Foretravel is now repairing older coach's bulkhead problems with HuckBolts, which I think is not a good choice because all blind fasteners can pull out of rusted, weakened inner-floor tubing. Foretravel has also used new Rolock bolts to repair bulkheads. I think some solutions are designed to pacify owners, speed up repair time and satisfy attorneys, rather than be the best in the long run. For a while we heard that bulkhead problems were caused by owners.
I have seen repairs that cut through the bottom of the floor to the rear of the rearmost 1-1/2" square tube and use 2" bolts & nuts to hold things together. This method cuts through a second square tube and removes the support the second tube offers.
Also some use stainless steel bolts, which will not rust, but are not as strong as grade 8 bolts. Stainless may be better though, as a rusted grade-8 will weaken over time.
There are many different solutions to bulkhead problems and many opinions offered by coach owners. And professional's solutions seems to change from time to time.
It does not help that fresh water tank overflows onto bulkhead, insuring it gets wet. Bulkhead repairs should also include strengthening the vertical steel braces, like was included in later designs.
Title: Re: bulkhead blues
Post by: Peter & Beth on July 03, 2012, 10:37:09 am
Curious, did they do sister bolts or replace the existing Roloks?
Sister bolts (using SS components)...but there's more to it than that. I had a complete rear bulkhead repair which included holding up the entire rear structure with bottle jacks so the remaining roloks could be cut off. This enables the acid wash (Ospho) and sealing of the remaining structure. Then the SS thru bolts are inserted in place after the structure is compressed together with clamps to ensure a tight seal and not crush the tubing by just torquing the bolt/washer/nut combination at each position. Not too technical, but that's the best I could do. A call to James Stallings will clear up any other questions you may have. He is very accessible by phone.
Peter
(edit) A long piece of fiberglass is used to seal up the underside of the floor structure to seal all the holes made to complete the process. I loved the result and how it looks.
Title: Re: bulkhead blues
Post by: wolfe10 on July 03, 2012, 11:18:16 am
A couple of observations:
1. I am not a fan of mixing metals, as galvanic corrosion is one of the causes of bulkhead issues. Said another way I would not favor stainless steel mixed with mild steel beams. And, yes I use a LOT of stainless steel on the boat.
2. There are several causes of bolt failure/bulkhead failure: a. Leaks in the wet bay-- could be from something as simple as bad gasket in the fresh water fill fitting. b. Rust jacking from salt up north or parking long-term on the beach and not washing it off. c. Water that gets in around the head of the Rolok bolts. This one affects ALL OF US. Remember, the 1/4" front of front bulkhead and rear of rear bulkhead is OVERDRILLED so that the Rolok will thread into the 1 1/2" box beam inboard of it. Water can enter the bulkhead area around the threads. When I re-did mine (just replacing a few broken bolts), I wire brushed the 1/4" angle, completely cleaned inboard to just a 1/2" or so onto the fiberglass center panel, masked off just the head of each bolt so it could be checked with a torque wrench later and then used 1/2 a can of undercoating to seal the area between 1/4" angle and the Rolok bolts. Bulkheads have remained perfect.
Again, if caught early, the fixes are simple and inexpensive.
Brett
Title: Re: bulkhead blues
Post by: Rudy on July 03, 2012, 11:34:17 am
My bulkhead was also done by Rance at Xtreme as per the specifications of James Stallings.
One would do himself a favor by talking with James about the pros and cons of the several offered repairs. Once you hear his learned thoughts, you will join Peter and I in knowing his repair is the preferred choice.
Title: Re: bulkhead blues
Post by: Don & Tys on July 03, 2012, 11:59:24 am
Brett, I had my concerns about the possibility of galvanic corrosion, but my research indicates that for this application, it won't be a problem. As well as the fact that Stainless fasteners are used in steel (and in aluminum as well) in automotive applications quite frequently. Now, I have wondered to no end whether or not the use of the thin aluminum trim piece that is inserted in the bulkhead joint at the factory that wraps around the edge of the fiberglass sheet may have contributed to the deterioration of the bulkhead joint, but that is history now! Following is an excerpt to the guide "Stainless Steel Fasteners Designer Handbook" found at this link http://www.ssina.com/download_a_file/fasteners.pdf (http://www.ssina.com/download_a_file/fasteners.pdf). Excerpt: "It is also important to have an understanding of the relative areas of the two different materials that are in direct contact with one another (the fastener system will normally represent the smallest surface area for materials being joined). Consequently, the fastener system should be cathodic to the materials being joined. This can be seen in the photographs showing the bolting materials used in the construction of the Thames River Barrier on page 14. In the aircraft industry, designers depend on this area-relationship principle when they specify stainless steel fasteners in aluminum structures. The greater the relative area of the anodic (aluminum material), the less severe is the corrosion. By comparison, steel or copper alloy studs for joining stainless steel would accelerate corrosion of the fastener system, although the extent of the galvanic attack would depend upon the relative area of each material. The area relationship depends not only on the relative area of the materials in the structure, but also on the number of fasteners. Sometimes an acceptable balance of incompatible metals may be achieved by adjusting the number of fasteners to distribute them more uniformly to avoid a local condition of low relative area. A general rule to remember is to use the more-noble metal for the part with the smaller surface area. This makes a good case for using stainless steel fasteners for joining metals that are less corrosion resistant... " Of course, this all just my opinion based on what I have read and some experience working on various mechanical things over the years... but what do I know, I am just a musician! In the end, I have to do what I feel will work best to let me rest easy that all the work I have done will have a good result, and on that account, I am satisfied that my Foretravel basment will last as long as the rest of the coach and then some. Don
1. I am not a fan of mixing metals, as galvanic corrosion is one of the causes of bulkhead issues. Said another way I would not favor stainless steel mixed with mild steel beams. And, yes I use a LOT of stainless steel on the boat.
2. There are several causes of bolt failure/bulkhead failure: a. Leaks in the wet bay-- could be from something as simple as bad gasket in the fresh water fill fitting. b. Rust jacking from salt up north or parking long-term on the beach and not washing it off. c. Water that gets in around the head of the Rolok bolts. This one affects ALL OF US. Remember, the 1/4" front of front bulkhead and rear of rear bulkhead is OVERDRILLED so that the Rolok will thread into the 1 1/2" box beam inboard of it. Water can enter the bulkhead area around the threads. When I re-did mine (just replacing a few broken bolts), I wire brushed the 1/4" angle, completely cleaned inboard to just a 1/2" or so onto the fiberglass center panel, masked off just the head of each bolt so it could be checked with a torque wrench later and then used 1/2 a can of undercoating to seal the area between 1/4" angle and the Rolok bolts. Bulkheads have remained perfect.
Again, if caught early, the fixes are simple and inexpensive.
Brett
Title: Re: bulkhead blues
Post by: Peter & Beth on July 03, 2012, 12:27:30 pm
If you want to do some reading on galvanic corrosion, then start here: Corrosion, stainless steel (http://www.mcnallyinstitute.com/04-html/4-1.html) Peter.
Title: Re: bulkhead blues
Post by: wolfe10 on July 03, 2012, 01:51:21 pm
Don,
Good point about having the fastener be the cathode and larger area being the anode, IF you have to have dissimilar metals. I guess my take is that I don't see an advantage to introducing a dissimilar metal as grade 8 steel bolts work very well.
Agree that we are likely splitting hairs on this-- either will make a great end-product.
I do feel strongly that one needs to spread the load on the box beam as I did with the mild steel rectangular "washers" I had made. With many kinds of fasteners it would be easy to crush the box beam before achieving adequate torque if the load were not spread to the top and bottom of the box by the rectangular washer. Can't see how a huck bolt would work, as it has no ability to spread the load sufficiently to load the top and bottom of the box vs just crushing the middle. If anyone has measured the spread of the huck bolt, would be interested to see exactly how far it does spread the load.
Clearly the extent of the repair depends on severity of the problem. Mine had a couple of broken bolts, zero rust, zero separation (Our coach has been in Texas all it's life and most of its time stored indoors when not in use). VERY different from some I have seen with long-time water leaks into the wet bay or coaches from up north where salt corrosion and rust jacking are issues.
Brett
Title: Re: bulkhead blues
Post by: travelite on July 06, 2012, 02:15:15 pm
Regarding the vertical supports you mention for the engine side of the bulkhead... when I am done with the re-skinning and I close the gap for the last time, I am welding some 3"X5"X3/16" rectangular tubing to the vertical angle iron bulkhead supports which go on either side of the two horizontal suspension/powertrain back bones with added 1/4" gussets between same. This will support the push/pull of the drive train and suspension so that the bulkhead is not the (nearly) sole support for the rear axle location. Attached is a mockup made out of the two supports and some triangular gussets. There will be two of these just inside of where the shackles meet the suspension. I believe this will offer adequate backing for the bulkhead joint, at least more than what it came with...
Edit for added content: Don
Hi Don,
You know how this goes... strengthen it in one place and concentrate the stress in another. I find it interesting that Rolok fasteners have lasted as long as they have in the Foretravel bulkhead application. Without doing a complete analysis, one reason might be the flexibility built in to the bulkhead where it meets the basement floor at the Rolok fastening point and also where it meets the horizontal suspension/powertrain backbone at the top of the bulkhead. In addition to these attachment points, there's flexibility of the bulkhead itself. Adding 3"x5" vertical stiffeners to the bulkhead may create stress concentrations elsewhere. Since the Roloks have lasted as long as they have, I'd be tempted to fix the fastener issue and leave the rest of the design more or less unchanged. Just my $0.02 :)
David
Title: Re: bulkhead blues
Post by: wa_desert_rat on July 06, 2012, 05:11:56 pm
Are the loads imposed by towing a car or trailer transmitted through the rear bulkhead? I am a little unlcear on the way it works for the unihome and unicoach designs.
Craig
Title: Re: bulkhead blues
Post by: Don & Tys on July 06, 2012, 05:55:25 pm
Craig, I fail to see how the loads could be imposed on the bulkhead joint, unless our coaches were front wheel drive ;D To me, it seems that that load is carried entirely by the power train frame work, which is very, very robust on our coaches. Most the tubing is 3/8" rectangular tubing, whereas on many SOB's they are largely made up of 1/4" or less "C" channel... And mostly bolted instead of welded. I think that the towing limits on our coaches are mostly just dependent on the hitch and power train's ability to move the loads... But then again, I am just a musician... LOL Don
Are the loads imposed by towing a car or trailer transmitted through the rear bulkhead? I am a little unlcear on the way it works for the unihome and unicoach designs.
Craig
Title: Re: bulkhead blues
Post by: Peter & Beth on July 06, 2012, 07:06:29 pm
I've heard that the retarder may be a compounding issue to the bulkhead separation. I suppose this may be true, but I do not know the design of the chassis in enough detail to support that theory. Peter
Title: Re: bulkhead blues
Post by: travelite on July 06, 2012, 11:21:37 pm
Craig, a while back someone posted a drawing of the rear substructure; I've attached a copy. I believe it came from Ray Stoltz, so it would apply to a 1993 U280.
David
Title: Re: bulkhead blues
Post by: wa_desert_rat on July 07, 2012, 01:36:19 pm
Craig, a while back someone posted a drawing of the rear substructure; I've attached a copy. I believe it came from Ray Stoltz, so it would apply to a 1993 U280.
David
David... thanks for that drawing. My stress analysis skills aren't what they used to be but that drawing makes me believe that there is some stress on the Rolocks on acceleration and especially when towing a vehicle. There would also be some load transmitted through the bulkhead if the towed vehicle applies brakes.
Most of the load would be carried on the top frame member but there would have to be at least some load on the Rolocks.
Unless, of course, my ME skills - never all that great anyway - are worse than I remember. :P
Craig
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 07, 2012, 01:56:40 pm
Looks like some of the load from acceleration or, I suspect more significantly, braking differential between front and rear could be on those bolted connections. Noting the broken verticals in the drawing it almost looks like it they could stand to be gusseted to the main frame, speaking strictly from the shade tree school of mechanical design.
Title: Re: bulkhead blues
Post by: Don & Tys on July 07, 2012, 02:16:30 pm
Edit: To add close up picture of cracked vertical angle iron bulkhead support. This one was taken when I first discovered it and had just cleaned the crud off so I could view it more clearly. There was no rust whatsoever involved in this failure. In my view, it was the stress of the bulkhead joint opening and closing after the failure of all or most of the Roloks.
My take on it is that when accelerating, the trailing arms which are attached to the drive axle are pushing on the bulkhead joint tending to close it. When braking with the rear wheels (exhaust brake or retarder), the joint is being pulled tending to open it. I don't think toad braking would have an much of an effect, unless you were dragging a sled or were towing something closer to the mass of the coach. Not that there wouldn't be some effect from toad braking, just not much... But in my opinion, accelerating with or without the toad would always be pushing the joint closer together because the drive wheels are pushing on the trailing arms which are attached to the angle iron and are what actually what locates the axel front to back. But this would probably never be an issue if moisture and or corrosive elements are kept away from the Roloks...
Those broken vertical pieces of angle iron are cracked or broken on mine as well and the 3x5" pieces of rectangular tubing I cut to fit are going to be welded right between them giving more surface are to weld gussets to join the horizontal and vertical main framing. As it is, I can open and close the bulkhead joint at will by removing the forward frame blocks and backing off the bulkhead joint fasteners because of the cracked or broken vertical angle iron pieces. I am attaching picture of the cracked supports... the rust visible in the picture was not a contributing factor. It is only surface rust which appeared after I cleaned the area with an angle grinder to get a better look at it. Don
David... thanks for that drawing. My stress analysis skills aren't what they used to be but that drawing makes me believe that there is some stress on the Rolocks on acceleration and especially when towing a vehicle. There would also be some load transmitted through the bulkhead if the towed vehicle applies brakes.
Most of the load would be carried on the top frame member but there would have to be at least some load on the Rolocks.
Unless, of course, my ME skills - never all that great anyway - are worse than I remember. :P
Craig
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 07, 2012, 02:49:43 pm
Today is a month since the pour so I drove out over the pit and did a quick inspection. Our U300 was always in a pretty dry area and when we bought it, the ODO was at 62,000 with never any winter or northern state trips. Underneath, there is a minimum amount of rust/corrosion, surprising since the front and rear subframes appear to have never had any kind of primer. Using a torque wrench, the first six bolts up front on the passenger's side and the first 5 in the rear, also on the passenger's side were broken, about a quarter inch from the head. The big angle iron is very clean. They have been broken for quite a while as none show any sign of a recent break. Rust jacking would seem to be the culprit with the angle iron forced out perhaps only a 32nd of an inch. They all line up exactly with the spray pattern off the tires when driving in the rain. Can't really figure out why only the passenger's side is affected. Ideas?
After viewing the drawing of the rear substructure and taking a close look at tube thickness, I am going to bolt through the rectangular tubing and make a conventional repair. Don't think the failure has anything to do with retarder (I don't have one) or towing, rather the design where the water and road chemicals can easily collect on top of the angle iron and also wick up from the bottom damaging both the bolts as well as the tubing. The catastrophic failures experienced by several forum members are the result of gradual breakage from rust jacking of the bulkhead bolts until there were not enough left to transfer the load to the rest of the possibly rust compromised steel structure forward of the substructure in my opinion. After the last one failed, some kind of momentary load caused the larger failure. Remember the failure of the EL AL 747 cargo plane engine bolts? Corrosion weakened them until one failed with the rest taking the increased load until they also failed and both engines fell off. Bad deal for the apartment complex.
Tank leakage may have also damaged the tubing in the cargo/tank floor until weakened members forced others to take loads from the rear substructure they were not designed for.
So, why just the right side both front and back? Anyone ever experience driver's side failures? Even if your coach has been stored in the desert, good idea to take a torque wrench to check.
Don't think with healthy bolts and rust free tubing, any normal RV related stress could possibly result in a problem.
Pierce
Title: Re: bulkhead blues
Post by: Dave M (RIP) on July 07, 2012, 02:57:08 pm
Pierc, Consider there is more water on the passenger side of road due to road crown, so I would guess there would be a little more spray from the right side wheels. ?? Dave M
Title: Re: bulkhead blues
Post by: Peter & Beth on July 07, 2012, 03:08:40 pm
Pierc, Consider there is more water on the passenger side of road due to road crown, so I would guess there would be a little more spray from the right side wheels. ?? Dave M
I was thinking the same thing...Crazy, eh? Donno. Who knows? Maybe even the road chemicals collect more so on the right side of the right lane due to the same crown!
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 07, 2012, 03:47:09 pm
I was thinking the same thing...Crazy, eh? Donno. Who knows? Maybe even the road chemicals collect more so on the right side of the right lane due to the same crown!
Good logic guys! Perhaps the right side tires run just to the right of passenger cars and collect more all the way from the passing/left lane.
How about the coach sits slightly low on the right side when parked from street crown and any water in the tube runs downhill and collects there?
Which side is the heavy side? Just guessing, would say it is the driver's side with generator, fridge, sink vs. fuel and radiator on right.
Pierce
Title: Re: bulkhead blues
Post by: wolfe10 on July 07, 2012, 05:02:51 pm
From the coach inspections I have done, there appear to be the three primary causes of bulkhead issues.
1. Leaks in the wet bay. In fact 2 to recent Foretravels had leaks for so long that the beams around the sewer door in the basement floor were rotted away. IMO, basically neglect.
2. Migration of water around the Rolock bolt threads because the 1/4" angle is (and has to be) over-drilled so the Rolock will thread into the box beam. Sealing around the head of the bolt (I mask off the part of the bolt where you would use a wrench) with undercoating, etc will seal that area to water intrusion.
3. Salt corrosion from up north of from parking on the beach without washing off the salt. Very rare on a coach from the south, unless they were beach-driven.
Brett
Title: Re: bulkhead blues
Post by: travelite on July 07, 2012, 05:58:11 pm
Today is a month since the pour so I drove out over the pit and did a quick inspection. Our U300 was always in a pretty dry area and when we bought it, the ODO was at 62,000 with never any winter or northern state trips. Underneath, there is a minimum amount of rust/corrosion, surprising since the front and rear subframes appear to have never had any kind of primer. Using a torque wrench, the first six bolts up front on the passenger's side and the first 5 in the rear, also on the passenger's side were broken, about a quarter inch from the head. The big angle iron is very clean. They have been broken for quite a while as none show any sign of a recent break. Rust jacking would seem to be the culprit with the angle iron forced out perhaps only a 32nd of an inch. They all line up exactly with the spray pattern off the tires when driving in the rain. Can't really figure out why only the passenger's side is affected. Ideas? Pierce
Pierce, It'd be really interesting to get a macro lens close-up of the sheared end of those broken bolts. Does anyone know if these bolts were plated or what exterior coating treatment was applied?
David
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 07, 2012, 08:59:24 pm
Pierce, It'd be really interesting to get a macro lens close-up of the sheared end of those broken bolts. Does anyone know if these bolts were plated or what exterior coating treatment was applied?
David
David,
Here is an example. They pretty much look all the same with the fracture at about a quarter inch.
Pierce
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 07, 2012, 09:07:39 pm
David,
I played with the focus, definition and sharpness on this one.
Pierce
Title: Re: bulkhead blues
Post by: John Haygarth on July 07, 2012, 09:21:02 pm
The reason Pearce that they are broken 1/4" from head is because that part is not into anything(holding)that is the angle iron thickness, so I would guess then that the bolts were holding fine in the tube, but broke because of the rust jacking. It tells me that the tube strength is fine, what do you think?? john
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 07, 2012, 09:36:17 pm
I know I'm in the minority here but really question the idea that these bolts are pulled apart due to pressures from rust jacking. I can see the angle between them swelling and being bent from rust jacking effect, can accept that the bolt can be weakened enough by corrosion and subsequent electroyitic action to break, but suspect an applied force is the culprit.
You've got a high tensile strength bolt with minimal threads in thin mild steel angle and tubing. I would think those threads would fail before the bolt would fail due to jacking tension. In looking at failed joints, is the angle iron straight between bolts or wavy?
Chuck
Title: Re: bulkhead blues
Post by: wolfe10 on July 07, 2012, 09:43:42 pm
The Rolock bolts break exactly where they torque into the "near side" of the box beam.
And rust jacking will break bolts on 18 wheelers with HUGE frame rails. Do a little research on rust jacking.
Brett
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 08, 2012, 12:37:23 am
The Rolock bolts break exactly where they torque into the "near side" of the box beam.
And rust jacking will break bolts on 18 wheelers with HUGE frame rails. Do a little research on rust jacking.
Brett
No need. Worked on rotating machinery pumping millions of gallons of saltwater a day for many years . The break location is at the most likely point of failure, obviously, as the angle is clearance drilled. These bolts corroded due to moisture intrusion around the head, intrusion exasperated by the locking serrations. Exactly what caused them to fail in their weakened condition is the issue.
Research torsional shear of radially loaded fasteners.
Chuck
Title: Re: bulkhead blues
Post by: Neal Pillsbury on July 08, 2012, 01:15:48 am
...................I know I'm in the minority here but really question the idea that these bolts are pulled apart due to pressures from rust jacking. ......................................
Chuck, I've always considered our bulkhead issue to be one of galvanic corrosion and tensile stress fracture/failure of the fasteners due to the forces imposed by rust jacking. Pierce's pictures of a failed fastener look just like many samples that I've seen and examined closely and they don't show evidence of radial or shear loading failures..............only tensile and galvanic corrosion failures.
"Rust-jacking" can occur with any joined-components that are made up of iron or steel. The only requirements are iron (Fe), oxygen (O₂) and a physical connection (bolt, spot weld, etc).
The "jacking" is the result of the chemical change that takes place when iron oxidizes (corrodes or rusts). As the iron rusts, it changes from iron to iron oxide and the resulting iron oxide occupies more volume than the original iron. It will exert tremendous force in doing so, if it is confined and the oxidation continues.
Depending upon a number of factors, the "swelling" of the iron oxide, can surpass the tensile, yield and fracture strengths of the physical connection (bolt or spot weld, etc.). Dependencies include the presence and concentration of things that aid in the oxidation process (presence of water or moisture, chlorides, heat, affected surface areas vs. bolting cross sectional area, affected surface preservatives, strength of the bolting, corrosion resistance of the bolting, galvanic cell values, etc.).
The nature of this volumetric expansion of the iron oxide is more than strong enough to force iron and/or steel joined-components apart and cause stress fractures of bolts in bridgework, skyscraper foundations, utility structures (and the frames of over the road vehicles) to the tune of multimillion's of dollars of annual damage nationwide. It is of particular significance to the trucking, utility transmission and distribution and salt water marine industries.
The accelerants that influence us FT owners the most, with our bulkhead joint design, are: 1. moisture/water 2. hygroscopic ("wicks" in water) liquid calcium chloride ions (from the ice preventative liquid highway treatments, rock salt residue to a lesser extent and salt air environments to a lesser extent yet.) 3. corrosion resistance of the fasteners that we use.
Thus, if we: 1. neutralize any corrosion (if present) 2. replace with corrosion resistant bolting (that is as galvanically neutral as possible in the joint) 3. exclude water from reaching the joint and fastener in the future
We will be on the clear success path.
Pierce, Many, if not most, of us with bulkhead bolting failures have seen more failures in the vicinity of the FW tank overflow (or other long duration wet bay leaks). Where is your overflow directed? If it is on the right side, don't forget that even though you may not overfill the tank, if it is anywhere near full, it will wet that side down each time you turn in that direction, until the volume is reduced sufficiently to prevent re occurrence. FWIW, Neal
Title: Re: bulkhead blues
Post by: Felix and Gail on July 08, 2012, 03:49:46 am
i agree with Neal. That is why I use SS bolts and now only fill the tank half way.
Title: Re: bulkhead blues
Post by: travelite on July 08, 2012, 08:30:43 am
I played with the focus, definition and sharpness on this one.
Pierce
Thanks Pierce for the pics, and thank you Neal for the explanation.
Pierce, have you removed any bolts that aren't broken? If so, it'd be interesting to take a close-up look at these.
Felix, what grade stainless?
David
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 08, 2012, 09:44:15 am
Nice explanation Neal, appreciate the detailed description. I'm not disagreeing with the concept of rust jacking, it was a common problem with saltwater pumps and mounts though the usual effect of it was seen in coupling misalignment over time. I've seen heavy flanges that were distorted between fasteners from rust pressure but can't say I've noted it pop bolts apart. It was pretty typical to see a splash zone centrifugal pump, motor and mount with so much active rust on it you really had to dig through it to even see the bolt heads. Many times these would break when attempting to loosen, and it was common to see a reduced diameter of the shank. It was common to see bolt heads so eroded by rust that flats were gone.
How many mild steel bolted connections do you have around the house and how many of them are falling apart due to rust jacking? I realize road salt spray is a factor, but living in Port Aransas where everything would be covered in a fine white coating of salt that would coalesce daily during the summer due to wind over a hypersaline water environment provided a pretty corrosive environment. My truck endured eight years of this, parked outside, and is still intact though more rusty than I would like on the underside. No sign of rust jacking failure in bolted, riveted or welded connections. Where it was a very real problem, however was not bolted connections at all but rebar improperly embedded in concrete. Now there's a good example of rust jacking.
Recognizing that pretty much everyone than me is accepting that this is the culprit, I'll state my thoughts and then shut up. Here are the factors I see involved in failure:
High tensile bolt with threads rolled into mild steel,water intrusion around bolt head=galvanic potential.
High tensile bolt held rigidly along the majority of its length due to these same rolled threads where it passes through members other than the clearance drilled angle iron=stress concentration.
Washer head bolt with gripping serrations held tightly against angle iron=increased stress concentration.
30K lb motorhome going over irregular surfaces with huge torque forces applied on the above=puny bolt failure.
Maybe shear isn't the right term as I tend to think of it as a guillotine type action and this is more like flex of the (extremely flex intolerant) bolt shank between the gripping washer head and the rigidly help portion of the bolt, in the area of the clearance drilled shank. I think this is what breaks these bolts, weakened in this area by corrosion. I suspect that if the number of fasteners had been tripled initially we wouldn't be seeing these failures. Take a look at a riveted wing spar, or for that matter the bridge over the Corpus Christi ship channel and note the concentration of fasteners for a very general comparison.
Anyhow, that's my take on it and I'm sticking to it until convinced otherwise. I appreciate everyone's willingness to discuss this stuff and hope my unwillingness to accept the rust jacking blanket explanation didn't get anyone's panties in a knot. It's in my nature to be intrigued by discussions of this nature and I do not mind being proven wrong.
Chuck
Title: Re: bulkhead blues
Post by: travelite on July 08, 2012, 10:18:30 am
Chuck,
Thanks for the candidness. What troubles me is that if there's no consensus on the cause, then can be no consensus on the fix. The foretravel community ends up with as many fixes as there are opinions. If the community erred on the conservative side relative to the cause and put together a universal fix based on this, then everyone could implement one fix. This fix would specify among other things: fastener count, fastener material, fastener size, fastener grade, fastener type (thru hole, blind), fastener spacing, joint treatment (anti-rust coatings, undercoats), etc.
David
Title: Re: bulkhead blues
Post by: wolfe10 on July 08, 2012, 10:40:49 am
David,
We may be "overthinking" this.
I have found very few failed bolts/bulkheads where the coach shows sign of previous bulkhead repair or just broken bolt replacement/sistering-- and it is something I check carefully on each coach I inspect.
Not sure there is one best fix, as the amount of failure varies so widely, as do the causes.
Brett
Title: Re: bulkhead blues
Post by: Peter & Beth on July 08, 2012, 10:47:29 am
Thanks for the candidness. What troubles me is that if there's no consensus on the cause, then can be no consensus on the fix. The foretravel community ends up with as many fixes as there are opinions. If the community erred on the conservative side relative to the cause and put together a universal fix based on this, then everyone could implement one fix. This fix would specify among other things: fastener count, fastener material, fastener size, fastener grade, fastener type (thru hole, blind), fastener spacing, joint treatment (anti-rust coatings, undercoats), etc.
David
Don't forget process! Peter
Title: Re: bulkhead blues
Post by: gam on July 08, 2012, 11:25:22 am
Has anyone ever sistered the joint with more 5/16" rolok screws? gam
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 08, 2012, 12:09:04 pm
I agree with Don that the towing capacity is only limited to what the driver is stupid enough to hook up to. The rear substructure is massive and would do all the pulling. A couple of months ago, I saw a U300 pulling an equipment trailer larger than the coach. It had a large backhoe plus other construction equipment and was heading down the road at 55 plus.
No, will have to wait until next week to pull bolts. Will drill a hole, stick my borescope in and post some interior tubing photos.
Decided to do conventional bolt through modification with washer/nut combination so I could examine the far side of the rectangular tubing at each location.
No, don't have a tank leak problem. The largest number of broken bolts were on the passenger's side up in front of the fuel tank (at the front of the coach). That is why I suspect the water,chemical and road debris throw back is responsible for the rust jacking.
Here is an excellent source of fasteners with all sizes of grade 8, zinc, hot dipped galvanized and stainless available with no minimum order: Bolt Depot - Nuts and Bolts, Screws and Fasteners online (http://www.boltdepot.com/Default.aspx)
Pierce
Title: Re: bulkhead blues
Post by: wolfe10 on July 08, 2012, 12:09:47 pm
Has anyone ever sistered the joint with more 5/16" rolok screws? gam
No, but have done and have seen others that have sistered with thru bolts. I understand others have done it, though.
I prefer the thru-bolts with large steel backing "washers" on the box beam, as it gives better holding on the box beam. Instead of threads gripping in each of the 1/8" box beam walls, the load is spread over a larger area side to side and to the horizontal section of the box beam by the steel backing "washers". Would be particularly important if there has been any degradation of the beam due to water intrusion.
Brett
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 08, 2012, 12:22:13 pm
Why not take a scientific approach, I'm sure there are engineers on the forum that would find this a piece of cake. I am not one of the lettered ones but this is the approach I would take.
Compressive strength of mild steel X Area of bolt head.
Tensile strength of bolt.
If the compressive strength exceeds the tensile strength then rust jacking can break the bolt.
Forces involved in torsion are more complex to figure but suspect that taking the area of the belly between bulkheads, weight at each corner, length of bulkheads would give a starting point. If the twisting force exceeds the shear or bending strength of one furthest outboard bolt, then the stage is set for torsional failure of successive bolts.
The truth is out there and I personally doubt there is any one force that causes failure, rather a compounding of issues and events. I haven't checked the bolts in the bulkheads of my coach, it's quite pristine underside having spent most of it's time in Tucson. Except for four months in Port A during which time I saw the rust/corrosion level double what it had acquired during its prior 14 years in Tucson. And then there was the time I dropped a front wheel off a steep shoulder at speed, producing enough body twist to unseat a windshield. Then there was the time before I owned it when it blew a tire and went offroad in Mexico, wiping out much of the front end. So, thinking about it, this is a pretty good test bed for the failure theories. This coach has taken some hard hits. There is almost zero rust underside. If there are no failed boats then I'll eat my words and accept that rust jacking is the primary culprit.
If I find a few broken bolts I will install more Rolocks then attempt to seal them and the seam to prevent moisture intrusion from below. If I find a lot of broken ones, assuming I can see through the tears, I'll affect a bolted fix with backing washers as suggested and attempt to inject an adhesive/sealant into the seam. I suspect I will own this coach for the duration so whatever it takes. Just last week I subtly hinted to my lovely wife that we might consider a newer Foretravel with slide when we are able to continue our travels. Her answer was quick and succinct. "Why? No. I like this one, a bigger one would just be more effort to clean."
Chuck
Title: Re: bulkhead blues
Post by: hotonthetrail on July 08, 2012, 12:27:53 pm
Check out Lowes Part number ZAB-241-3/8 Superstrut these are 1/4" thick steel plates 1&1/2" square goldguard 3/8" bolt hole plates by Thomas&Betts located in the electrical dept. bag of 5, this is not junk stuff. UPC code 75114 01390. Made in the USA. May want to put caulk between plate and tubing. thats it jc
Title: Re: bulkhead blues
Post by: Gary Bouland (RIP) on July 08, 2012, 12:40:14 pm
Quote
No, but have done and have seen others that have sistered with thru bolts. I understand others have done it, though.
I prefer the thru-bolts with large steel backing "washers" on the box beam, as it gives better holding on the box beam. Instead of threads gripping in each of the 1/8" box beam walls, the load is spread over a larger area side to side and to the horizontal section of the box beam by the steel backing "washers". Would be particularly important if there has been any degradation of the beam due to water intrusion.
Brett
Brett, A question about ROLOKS, Do I understand correctly that these are THREADED only thru the box beam ? If so this is very few threads due to thickness of boxbeam. Gary B
Title: Re: bulkhead blues
Post by: Don & Tys on July 08, 2012, 01:58:06 pm
This part is potentially usable, but it is 1 5/8" square and so you would have to grind a (at least) 16th" off of two opposing sides in order to leave the hole centered to fit the inch and half square tubing. Probably easier to buy 1/4" by 1&1/2" flat stock and make your own, especially if you have a drill press. That way you can spread the force laterally as well... Don
Check out Lowes Part number ZAB-241-3/8 Superstrut these are 1/4" thick steel plates 1&1/2" square goldguard 3/8" bolt hole plates by Thomas&Betts located in the electrical dept. bag of 5, this is not junk stuff. UPC code 75114 01390. Made in the USA. May want to put caulk between plate and tubing. thats it jc
Title: Re: bulkhead blues
Post by: wolfe10 on July 08, 2012, 02:05:07 pm
Brett, A question about ROLOKS, Do I understand correctly that these are THREADED only thru the box beam ? If so this is very few threads due to thickness of box beam. Gary B
Gary,
You are correct-- they are threaded through both 1/8" walls ONLY. Obivously, the 1/4" is over-drilled so that the Rolocks will torque into the box beam.
That is why I like the thru bolts with large flat metal "washer". I had mine made by a machine shop from 1/4" steel very inexpensively. They cut it into strips, I used my drill press to make the hole and then I cut the "washers" to length with a hack saw.
Pierce-- yes, please post after you have put a torque wrench on your bulkhead bolts. Thanks.
Brett
Title: Re: bulkhead blues
Post by: gam on July 08, 2012, 02:19:14 pm
I find it int erasting that there are 3 roloks close together on each end of the bulkhead. Did Foretravel expect a twisting action of the bulkhead when breaking? Like a chain a number of small fasteners holding something together is only as strong as the one taking the load. As for holding power in thin wall tubing ,I have never seen a rolock pull out only break.I have seen rust jacking in masonry and concrete construction and in some structural fabrication of heavy steel. But not to bolt failure in light weight fabrications like the tubing angel iron of the bulkhead. I thing you will find very little rust in the area of metal to metal contact under the screw head and between the parts in that area. Most of the joint opening will be between the screw holes and put little load on the roloks. But will this allow more twisting of the bulkhead and more load on one or two of the screws when breaking ? This is just me thinking out loud! As for a fix , grade 8 through bolts and rectangular washers' . But I just don"t like using a holesaw on my baby. Gam
Title: Re: bulkhead blues
Post by: hotonthetrail on July 08, 2012, 03:00:04 pm
Is there a reason why the treads could not be on the outside, easier to torque , protect and inspect etc.? jc
Title: Re: bulkhead blues
Post by: wolfe10 on July 08, 2012, 03:34:03 pm
Is there a reason why the treads could not be on the outside, easier to torque , protect and inspect etc.? jc
There is no access to the "back" (center of the coach) to install a bolt. You could do that as a repair, but have a minor preference for not having exposed threads, washer and nut outside in the elements. Would still need the large rectangular washer to spread the load on the box beam.
Brett
Title: Re: bulkhead blues
Post by: Dave Cobb on July 08, 2012, 04:12:42 pm
Is there a chance that the Roloxs might have been over torqued when installed? Might this help account for the number of broken bolts found on coaches without much rust jacking? Or the missing of just an occasional bolt head or two?
Title: Re: bulkhead blues
Post by: wolfe10 on July 08, 2012, 04:40:23 pm
Dave,
Rare, but yes. I had one that I suspect was broken during installation. I am saying that because yellow 3M weather strip glue was used to hold the head of one of the Rolocks in place! That is the only one I have found like that on any coach that I have checked with a torque wrench. But it CAN happen.
Title: Re: bulkhead blues
Post by: Felix and Gail on July 08, 2012, 06:36:04 pm
David, I used 304 ss which is what my hardware store carried. I had used a adhesive caulk to seal the seam, 3M5200 but it is not holding up and am in the process of scraping it off. It came off fairly easy after using brake part cleaner and wire brush. I ordered a starter kit of POR 15 to seal the area. It seams to have the charecteristics to inhibit rust and form a good seal, although I have never used it before.
Title: Re: bulkhead blues
Post by: gam on July 08, 2012, 08:43:11 pm
3/8" 304 stainless steel bolts with 304 nuts have a torque rating of only 216 in=lbs or just under 18 ft-lbs. Gam
Title: Re: bulkhead blues
Post by: Don & Tys on July 08, 2012, 10:25:47 pm
My (& Tys's) 400th post! You guys with several thousand... Don't laugh! Oh, go ahead and laugh ;D Now to the point... The ARP 300 series 3/8" fasteners that I am using have a lubed torque spec of 45ft lbs... I have no intention at this point of torquing them that tight, rather I plan to use loctite to lube and secure the bolts at around 30ft lbs. My experiments show that 1.5" Square X 1/8" thick walled tubing crushes at about 33ft lbs. when using ARPS ultra torque lube. I could post a YouTube video of that if anyone cares to see it... Now my particular installation has a sistered 1/8" square tubing along the bulkhead, backed in most places with welded 3/16ths angle iron and in a few spots with 1/8" angle iron. The angle iron also serves to give me a way to mount the aluminum plates that I am using in place of the original plywood which destroyed the integrity of most of the frame in contact with it because was so saturated with moisture from freshwater leaks. Weld nuts are welded to the angle iron, so I will be able to remove the bolts if it is ever necessary for some reason. Because I was able to reuse all but one of the original holes (because one of them went into a longitudinal part of the frame, that one I drilled a fresh hole for), there are 17 of these fasteners across. The outer ones are 3" long because they only go through the 1/4" bulkhead angle iron and one cross section of the the transverse frame member, the other 15 fasteners which have to go through 3" worth of square tubing, a 1/4" angle iron and a 3/16" angle iron are 4" long. I was able to use even the outer most holes because I replaced the outer longitudinal frame members on both sides, each of which I welded into place after welding a nut on the transverse tube that is inside the outer longitudinal frame members. As you might imagine, I never want to have to do this again! These ARP fasteners are expensive at about $5 apiece, but compared to the totality of the project, it doesn't amount to much. Here is picture of the fasteners... pity no one will ever see them as they are pretty things.
3/8" 304 stainless steel bolts with 304 nuts have a torque rating of only 216 in=lbs or just under 18 ft-lbs. Gam
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 08, 2012, 10:43:06 pm
Art,
First class work, I suspect you will have the highest structural integrity possible as a result. Nice selection of materials, innovative modifications. Hats off to you and Tys.
Chuck
Title: Re: bulkhead blues
Post by: Dwayne on July 08, 2012, 11:34:47 pm
Just curious...how much does FOT charge to fix this very poor design flaw?
Title: Re: bulkhead blues
Post by: Don & Tys on July 08, 2012, 11:38:30 pm
Thanks Chuck! Structural integrity is what I am most concerned about, but the fluff (such as electronics upgrades and the like) are definitely more fun... can't wait to get to that part ::) Don
First class work, I suspect you will have the highest structural integrity possible as a result. Nice selection of materials, innovative modifications. Hats off to you and Tys.
Chuck
Title: Re: bulkhead blues
Post by: Dave Cobb on July 09, 2012, 12:14:38 am
As to cost, Foretravel repaired my rear bulkhead. Wayne removed all the old bolts, or cut them, treated the area, installed two thru bolts to hold the floors up while working on the open areas between the angle and the box steel. He then installed 16 Hucks, resealed, and added a cover strip and sealed that along with the two plugs to cover the cut outs in the fiberglass belly pan. Total cost was around $900 dollars.
Seeing him doing the work, over the course of two days, with all the correct equipment and experience, after reading, gathering some of the parts, and discussions with others that had done the repair, I think it a bargain. Plus several "free" night at Camp Foretravel were included as well.
Title: Re: bulkhead blues
Post by: travelite on July 09, 2012, 01:23:51 am
What we don't want is joint separation at the bulkhead angle iron to basement floor interface as we're driving down a bumpy road. There should be enough Rolok clamping force preload to prevent this. Fasteners aren't my field but I managed to dust off some formulas.
The Rolok spec says that the 5/16th inch part should be torqued to 250 in-lbs. The clamping force per bolt would be F(bolt)=T/(K*d) where F(bolt) is the clamping force, T is the tightening torque applied (250), d is the nominal bolt diameter (0.3125), and K is a correction factor that depends on the material, size, friction, and thread of the bolt. For small diameter zinc plated bolts K would be around (0.2).
So the clamping force per bolt would be: 250/(0.3125*0.2)=4000 lbs. If we assume there are 17 Rolok fasteners then the total clamping force would be 68000 lbs. Now we need to correct for the 1/8" wall thickness of the basement box tube member, or what I call the 'nut'. This nut thickness allows for only 2.25 threads of engagement instead of the optimal 5.6 threads of engagement.
Dusting off more formulae. The clamping force of the nut F(nut)=t*A*C1*C2, where t is the nut material shear strength (20000 psi, or 60% of proof), A is the nut shear area, C1 is the nut dilation factor (1.0 for this case), and C2 is the nut thread bending factor (0.897).
The nut shear area A=((pi*d*m)/P)*(P/2+(d-D)/sqrt(3)), where d is the thread major diameter (0.3125), P is the thread pitch (0.0556), m is the thread engagement length (0.125), and D is the nut pitch diameter (0.2817). The nut shear area, A, is then 0.1006 and the clamping force provided by each nut, F(nut), is 1800 lb. If there are 17 Roloks then our clamping force is reduced from 68000 lbs, calculated based on the bolts, to (1800*17) = 30600 lb when we consider the nut.
Then we need to derate for installation error. If the installer over or under torqued a bolt then the other bolts need to carry a higher load. Then there's the issue of rust developing inside the box tubing over time degrading the rolled threads. Then there's the issue of bolt alignment - is the Rolok reasonably true and perpendicular to the clamped surface. Then there's the issue with the Rolok's being of a much harder material than the nut; i.e., there's no hardened washer bearing surface between the Rolok and the 1/4" transverse angle member. Cyclic loads and micro-vibrations may allow the Rolok to wear into the transverse member in which case one or more Roloks will lose their preload.
Then we need to consider the load. Some number crunching I did some time ago shows that static load on the lower bulkhead may be as high as 15000 lb. I believe typically you'd design for a safety factor of 3 to handle dynamic loads which would put us at a desired design strength of 45000 lbs. An example of dynamic loading is braking. Say you're braking at 1/2g. The drive axle can carry as high as 20000 lbs of load. One half g of braking exerts a force of 10000 lbs at the tire/road contact area of the drive axle tires which translates into as high as a 15000 lb force at the lower control arms. This puts us well into our F(nut) strength territory of 30600 lb.
The picture I'm painting is that the Roloks may suffer joint separation, that is, the external loads may overwhelm the Rolok preload. If the joint separates, then all of the load falls onto the bolts - the joint no longer supports any load whether torsion, bending, tensile, or shear.
It's late. I'll check my numbers in the morning. David
Title: Re: bulkhead blues
Post by: Don & Tys on July 09, 2012, 01:47:18 am
I don't See where you accounted for the fact that the Roloks all go through at least two 1/8" thick walls of the tubing, which I think adds an interesting wrinkle to the calculations, especially when you consider that five or so street side Roloks go through an additional 1/16" wall of tubing where it is doubled up. Also the fact that the Roloks are engaging both front and back walls of the eighth inch tubing means that there is no crushing force exerted on the tube. About five or six of mine were broken off inside the transverse tube (well past the usual 1/4" mark and still had a grip on the near side. None of the bolts had a "nut" failure except one, which in which I believe was stripped on installation. It was the only completely intact fastener! Don
What we don't want is joint separation at the bulkhead angle iron to basement floor interface as we're driving down a bumpy road. There should be enough Rolok clamping force preload to prevent this. Fasteners aren't my field but I managed to dust off some formulas.
The Rolok spec says that the 5/16th inch part should be torqued to 250 in-lbs. The clamping force per bolt would be F=T/(K*d) where F is the clamping force, T is the tightening torque applied (250), d is the nominal bolt diameter (0.3125), and K is a correction factor that depends on the material, size, friction, and thread of the bolt. For small diameter zinc plated bolts K would be around (0.2).
So the clamping force per bolt would be: 250/(0.3125*0.2)= 4000 lbs. If we assume there are 17 Rolok fasteners then the total clamping force would be 68000 lbs. Now we need to correct for the 1/8" wall thickness of the basement box tube member, or what I call the 'nut'. This nut thickness allows for only 2.25 threads of engagement instead of the optimal 5.6 threads of engagement.
Dusting off more formulae. The clamping force of the nut F(nut)=t*A*C1*C3, where t is the nut material shear strength (20000 psi, or 60% of proof), A is the nut shear area, C1 is the nut dilation factor (1.0 for this case), and C3 is the nut thread bending factor (0.897).
The nut shear area A=((pi*d*m)/P)*(P/2+(d-D)/sqrt(3)), where d is the thread major diameter (0.3125), P is the thread pitch (0.0556), m is the thread engagement length (0.125), and D is the nut pitch diameter (0.2817). The nut shear area, A, is then 0.1006 and the clamping force provided by each nut, F(nut), is 1800 lb. If there are 17 Roloks then our clamping force is reduced from 68000 lbs, calculated based on the bolts, to (1800*17) = 30600 lb when we consider the nut.
Then we need to derate for installation error. If the installer under-torqued a bolt then the other bolts need to carry a higher load. Then there's the issue with the Rolok's being of a much harder material than the nut; i.e., there's no hardened washer bearing surface between the Rolok and the 1/4" transverse angle member. Cyclic loads and micro-vibrations may allow the Rolok to wear into the transverse member in which case one or more Roloks will lose their preload.
Then we need to consider the load. Some number crunching I did some time ago shows that static load on the lower bulkhead may be as high as 15000 lb. I believe typically you'd design for a safety factor of 3 to handle dynamic loads which would put us at a desired design strength of 45000 lbs. An example of dynamic loading is braking. Say you're braking at 1/2g. The drive axle can carry as high as 20000 lbs of load. One half g of braking exerts a load of 10000 lbs at the tire/road contact area of the drive axle tires which translates into as high as a 15000 lb force at the lower control arms. This puts us well into our F(nut) strength territory of 30600 lb.
The picture I'm painting is that the Roloks may suffer joint separation, that is, the external loads may overwhelm the Rolok preload. If the joint separates, then all of the load falls onto the bolts - the joint no long supports any load whether torsion, bending, tensile, or shear.
It's late. I'll check my numbers in the morning. David
Title: Re: bulkhead blues
Post by: Barry & Cindy on July 09, 2012, 02:02:50 am
I think I read that some are considering using steel backing plates that are pre-drilled, but that really doesn't work. Drilling holes in angle iron and tubing for bolts & nuts ends up not being perfectly centered in the tubing.
We found that after drilling we placed the backing plate against the tube and 'marked' the backing plate with the drill bit. Then the backing plates were removed and then the bolt hole is drilled where the mark is.
Painting the backing plates white will help see the drill bit mark.
Title: Re: bulkhead blues
Post by: travelite on July 09, 2012, 08:46:10 am
I don't See where you accounted for the fact that the Roloks all go through at least two 1/8" thick walls of the tubing, which I think adds an interesting wrinkle to the calculations, especially when you consider that five or so street side Roloks go through an additional 1/16" wall of tubing where it is doubled up. Also the fact that the Roloks are engaging both front and back walls of the eighth inch tubing means that there is no crushing force exerted on the tube. About five or six of mine were broken off inside the transverse tube (well past the usual 1/4" mark and still had a grip on the near side. None of the bolts had a "nut" failure except one, which in which I believe was stripped on installation. It was the only completely intact fastener! Don
Don, I'm not following you. Maybe you can draw a picture of what the bolted Rolok joint looks like?
David
Title: Re: bulkhead blues
Post by: Don & Tys on July 09, 2012, 01:50:44 pm
David, I don't have the time just now, but maybe this picture will suffice. This is taken from the street side with the bulkhead on the right hand side of the picture. The first 18" or so of the transverse 1&1/2 X 1&1/2 X 1/8" is doubled up with 16 gauge tubing. Just past that, you can hopefully see the end of a broken Rolok sticking through the eighth inch transverse tube. So the 3" Rolok bolt passes through the 1/4" angle iron, some 16 gage (or thereabouts) sheet metal which is the actual bulkhead partition, then the near side of the square inch and a half eighth inch tube, and finally the opposite side of the transverse tube. For that first section which has the sistered 16 gage tubing, the 3" Rolok also passes through and threads into one wall of that tubing. Thus the nut thickness is two cross sections of the tube and because the threads are cut when the Rolok is installed, it is applying clamping force to both vertical walls of the square tubing at the same time, eliminating crushing tendencies. and possibly adding some binding component to secure the bolt better than would be the case with one thicker wall, but not really sure about that. I hope that helps clarify things... Don
Don, I'm not following you. Maybe you can draw a picture of what the bolted Rolok joint looks like?
David
Title: Re: bulkhead blues
Post by: nitehawk on July 09, 2012, 02:50:54 pm
Can't find my Bendix-Besly tap book right now, but if I recall, approximately 1-1/2 times the thread dia for length engagement, at 72% of thread form in the "nut" the bolt will break before the threads strip in the female part (nut). I can't remember whether it was for grade 8 bolts or not. I think aluminum length of engagement had to be 2+times the thread dia.
The above info is from Bendix-Besly Tap Mfg Co. technical book. Usually a pretty good source of information and something for everyone to consider when determining if they have enough holding power for an object that goes down the road subject to bouncing, heat, rust jacking, and all the other stresses put on our coaches.
Title: Re: bulkhead blues
Post by: travelite on July 09, 2012, 05:22:38 pm
Thanks Don, I see what you're talking about.
There's no bolt stretch at the center of the box section. All the preload clamping force is between the bolt head and the 'nut' at the box section front face, and it's mostly at the first two threads of the 'nut'. We need material there to help support the nut so it doesn't deform and strip. Because the nut deforms we live with a lower preload force. Having a threaded back face does give us redundancy - if the front face threads fail, then we can preload with the 'nut' at the back face. Now we have bolt stretch at the center of the box section, and we again have preload.
As a thought experiment you can take this to extremes. Say you have 8 thin walls of 1/32" that are spaced evenly in the 1 1/2" box section. Is this equivalent to one 1/4" nut? David
Title: Re: bulkhead blues
Post by: wolfe10 on July 09, 2012, 06:04:55 pm
David,
With VERY rare exception, when I inspect bulkheads with a torque wrench, the Rolock will either torque up to 250 inch-lbs or be broken. Very few are loose and will torque up.
And as most have found they break where the Rolock threads into the "nearer" side of the box beam.
I have yet to break a Rolock by torquing them-- easy to determine, as 100% of the breaks were rusted, not fresh breaks.
Best advice, as I posted 3 years ago, is to put a torque wrench on the bulkhead bolts once a year. View it a routine maintenance (which it is) and it is a lot less intimidating that letting it go until it is a big problem.
Brett
Title: Re: bulkhead blues
Post by: travelite on July 09, 2012, 06:13:29 pm
Brett,
I second your advice. Everyone should have their Roloks periodically torqued. I'd add to the protocol by suggesting that folks first back off the Rolok and then torque it. This will help detect bolts that are rusted in place. A bolt could be rusted solid and it will pass the torque test, but it may have long ago given up it's preload. By backing it off first, we can then torque it to the proper spec and rest assured that the preload is restored.
Also, I wouldn't use Loctite. Loctite can mask preload issues. I'd put anti-seize on the bolts. I'd want them in a condition where the can readily and routinely be checked. David
Title: Re: bulkhead blues
Post by: wolfe10 on July 09, 2012, 06:31:41 pm
David,
Particularly after sealing around the shoulder of the Rolock (I used regular automotive undercoating) I would not back off the Rolock. Again, in the hundreds I have checked, they are either broken or will torque up. I would not break them loose just to test. Loosening first would open up the potential to break a perfectly good bolt with good clamping force if rust/corrosion between threads and the two sides of the box beam increased torque needed to break it loose to the point of bolt failure.
Brett
Title: Re: bulkhead blues
Post by: travelite on July 09, 2012, 06:42:11 pm
I defer to your knowledge and experience Brett.
David
Title: Re: bulkhead blues
Post by: gam on July 09, 2012, 07:09:50 pm
I think if the 1/8" walls take the torque load one at a time . The joint only has the tensile strength of the threads in the first wall. When the first wall fails the screw must be re torqued to restore the clamping force. The rolled threads made by a 5/16" rolock and a .277 pilot drill have 100% thread contact and are much stronger then cut threads. After taking a torque load a screw with that much thread contact tends to seize up and can not be backed off,only tightened.The failed rolocks used in the bulkhead have the heads broken off not the threads stripped. The exception to this may be over torqued. 5/16" Rolocks should not be used with a wall thickness of less the .109". I agree that the way to go is torque check ,clean rust, seal joint, and replace failed Rolocks with through bolts and I wouldn't use any penetrating oil on the joint. Gam
Title: Re: bulkhead blues
Post by: travelite on July 09, 2012, 07:20:41 pm
Thanks Joseph, I agree, though I'd add that nut failure doesn't need to take the form of stripped threads. All that's required is that the nut deform such that preload is lost. If this happens then the lower bulkhead can experience joint separation under load, meaning that the external applied forces overwhelm the remaining bolt clamping preload. Once this occurs the joint has failed. Now all the load is taken by the bolts with none supported by the bolted joint. At this point failures can occur in many ways including what we've seen to date. Couple this phenomenon with stress corrosion and you may have what we're seeing today. David
Title: Re: bulkhead blues
Post by: gam on July 09, 2012, 08:12:05 pm
Well I guess you can beat a dead horse. We each just have to deal with what we have .But I do think we should as a group standardize on one or two types and sizes of bolting as a repair or replacement for the rolocks. I think this would be best for everyone and for Foretravel and I do think that Wolfe is on the right track. Gam
Title: Re: bulkhead blues
Post by: travelite on July 09, 2012, 11:09:52 pm
I do think we should as a group standardize on one or two types and sizes of bolting as a repair or replacement for the rolocks. I think this would be best for everyone and for Foretravel and I do think that Wolfe is on the right track.
You and me both. I think this would be a great outcome.
David
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 09, 2012, 11:13:09 pm
Gam,
Beating a dead horse is better than beating a dead coach by the side of the road. While our rigs have few flaws, the bulkhead problem along with rust damage to the floor tubing are major issues with different solutions to different areas of damage. Don's damage was extensive and required major work (that he did an outstanding job on) while others will only need to check on a regular basis with a possible replacement of a few bolts. The more we read about others problems, the better understanding we have as to the causes, what to watch for on our coaches as well as what to check when we survey a potential new acquisition. Very important to make this inspection a part of a regular maintenance schedule for new owners and members of the forum.
OK, out to check on my slightly limp horse and make sure a new shoe takes care of the problem.
Pierce
Title: Re: bulkhead blues
Post by: gam on July 09, 2012, 11:38:32 pm
Pierce What you wrote is completely correct. But I was only talking about the Rolock repairs or replacement. Foretravel has a repair kit ,but no instructions with it. I just hate to think of a foretravel going down the road with slick headed bolts holding it together. Gam
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 09, 2012, 11:48:25 pm
Pierce What you wrote is completely correct. But I was only talking about the Rolock repairs or replacement. Foretravel has a repair kit ,but no instructions with it. I just hate to think of a foretravel going down the road with slick headed bolts holding it together. Gam
Gam,
Not a dig at all. I was just so surprised when my apparently almost rust free U300 had 5 and 6 bolts in a row break off on the one side. Just had to ramble a bit for any new members who might be fat and happy like I was BTW (before torque wrench). ;D
Pierce
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 10, 2012, 12:18:59 am
It's fortunate that re securing the bulkheads is a pretty simple task provided it's caught before separation. In the grand scheme of motorhome ownership this is a trivial fix...provided it's caught early on. It's also fortunate that the procedure for checking is well documented.
There are a number of ideas on what causes these failures, the most accepted and popular of which I seriously doubt. I think what it comes down to is this. The connection is marginal, even without the environmental degradation that comes with use. The joint needs to be stronger. More fasteners. Travelite laid it out pretty well with his calculations.
More Rolocks and protection for them seems to be the best choice. They have some strong advantages over drilled and bolted connections. I see Rolocks as studs, bolts as compression fasteners. I suspect that's why they were chosen originally rather than for ease of production.
Chuck
Title: Re: bulkhead blues
Post by: wayne m on July 10, 2012, 08:59:08 am
it appears we have gone full circle on this issue, and not understanding all the engineerspeak, the question remains. if one finds a few broken bolts, is it better to through bolt with nuts and a heavy washer or remove the old bolt and replace with larger rolok? I like gam's idea of coming to a general concensus of the group for the best fix. at first I liked the idea of the bolts and nuts, now i'm not so sure. back to square one.
Title: Re: bulkhead blues
Post by: travelite on July 10, 2012, 12:09:37 pm
If you sister with additional Roloks, how do you make sure that they're installed straight and true? If the bolt flange doesn't seat flush with the clamped joint then the bolt shank is both under tension and bending which means, guess what? More preload derating... For the shade tree mechanic, nuts and bolts are more foolproof - but even so, one needs to be careful of bending which is easier to avoid if you're only bolting the front two faces together, not thru bolted.
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 10, 2012, 01:18:15 pm
If you sister with additional Roloks, how do you make sure that they're installed straight and true
Good point. Short of using a drilling jig or just being lucky/good, don't know. Of course if the flanges aren't tight when drilled they will change alignment a bit also. Maybe flanged nuts and bolts are the best way to go. At least you can understand what's happening when you tighten them up.
Title: Re: bulkhead blues
Post by: gam on July 10, 2012, 02:30:32 pm
Something for those with torque wrenches. When I had a job{before SS } every year new or old I had to send out for calibration the 20 or 25 torque wrenches we used during our plant outages. The calibration of the wrench can be checked at home very easily. Check on line. Of the ones sent out 5 or more would be out by more then 10%.when not in use the scale on the snap wrench's should be turned back to zero to prevent the internal spring from taking a set. Gam
Title: Re: bulkhead blues
Post by: Roland Begin on July 10, 2012, 03:45:06 pm
I was working on my coach today getting ready to repair my forward bulkhead. As described in a previous post I had major bulkhead failure in Louisanna. In stripped the Filon and cleared out the blue insulation getting ready to drill holes for the throughbolts. As I was looking at the assembly I stated wondering why during the initial build did they not weld the angle iron and the box beam together? Seems to me a welded joint would be a bit stronger, and require less specialized equipment than the rolok bolts? Wouldn't be any spray leaching up between the joint to cause rust jacking and snapping bolts. The only reason that I bolt things together is to be able to take them apart in the future. This does not look like something you would want to dis-assemble. Inquiring minds would like to know.
Roland
Title: Re: bulkhead blues
Post by: travelite on July 10, 2012, 06:43:53 pm
I was working on my coach today getting ready to repair my forward bulkhead. As described in a previous post I had major bulkhead failure in Louisanna. In stripped the Filon and cleared out the blue insulation getting ready to drill holes for the throughbolts. As I was looking at the assembly I stated wondering why during the initial build did they not weld the angle iron and the box beam together? Seems to me a welded joint would be a bit stronger, and require less specialized equipment than the rolok bolts? Wouldn't be any spray leaching up between the joint to cause rust jacking and snapping bolts. The only reason that I bolt things together is to be able to take them apart in the future. This does not look like something you would want to dis-assemble. Inquiring minds would like to know.
Roland
I'm no welding expert, but I think it's cause it's bad form to put a weld in bending: Don't Put Welds in Bending (http://weldingdesign.com/blodgett/wdf_10950/). To keep the weld bead (root, toe, and face) out of the compression and tension of bending will require a connection redesign. David
Title: Re: bulkhead blues
Post by: gam on July 10, 2012, 07:15:32 pm
To assure alignment of any new bolt holes two very simple fixtures can be fabricated by anyone with a lath and welder available to them. The first would be a plate about 4" in dia with a 1/2" dia shaft about 1 1/2" long welded to the center of it. A hole the dia of the new Roloks would be drilled through the center of the shaft and through the plate. the under side of the plate would be machined to make it flat and 90 to the drilled hole. This fixture can be used as a drill guide to drill the hole through the angle iron for the new screw. A collar stop on the drill will prevent over drilling in depth . A fixture for the pilot drill would be fabricated in the same way ,except it would have an embossment the dia of the first brill hole on its under side. this will center the pilot drill in the first hole. I will be picking up a torque wrench at one of the plants I worked at in the next few days . I hope I will have to do none of this . But if I do I'm thinking of replacing all the 5/16' roloks with 3/8" roloks. The install or drive torque is about the same at 130 inch pounds. So I'm thinking of a finish torque of about 270 inch pounds . Gam
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 10, 2012, 08:45:10 pm
It would be interesting to know how the factory does, or did the drilling. Suspect the angle was predrilled, the rest field drilled. Redundancy can make up for derating.
Title: Re: bulkhead blues
Post by: travelite on July 10, 2012, 09:42:40 pm
To assure alignment of any new bolt holes two very simple fixtures can be fabricated by anyone with a lath and welder available to them. The first would be a plate about 4" in dia with a 1/2" dia shaft about 1 1/2" long welded to the center of it. A hole the dia of the new Roloks would be drilled through the center of the shaft and through the plate. the under side of the plate would be machined to make it flat and 90 to the drilled hole. This fixture can be used as a drill guide to drill the hole through the angle iron for the new screw. A collar stop on the drill will prevent over drilling in depth . A fixture for the pilot drill would be fabricated in the same way ,except it would have an embossment the dia of the first brill hole on its under side. this will center the pilot drill in the first hole. I will be picking up a torque wrench at one of the plants I worked at in the next few days . I hope I will have to do none of this . But if I do I'm thinking of replacing all the 5/16' roloks with 3/8" roloks. The install or drive torque is about the same at 130 inch pounds. So I'm thinking of a finish torque of about 270 inch pounds . Gam
Joseph, I understand that if the 5/16" Rolok is broken it can be fixed by putting in a 3/8", assuming a clearance hole is drilled into the 1/4" angle iron. In either case, you're still limited by the 0.125" nut size. Your finish torque will need to be adjusted based on the nut. I think you'll find the clamping force will be essentially unchanged. I'm with Chuck, redundancy - multiple load paths. Chuck said earlier that if Foretravel had used 3x as many Roloks we wouldn't be seeing this problem. I like your plan - I'm not fond of mixing fastener sizes either. Make 'em all 5/16th's or make 'em all 3/8th's. David
Title: Re: bulkhead blues
Post by: Don & Tys on July 10, 2012, 10:10:39 pm
I don't know how that did the drilling, but in our coach, there was quite a bit of variability in the angle of the bolt holes. Some were significantly off of perpendicular and one ended up at the intersection of one of the longitudinal frame members. Also, the spacing was not uniform but looked pretty seat of the pants to me. The fact that the coach stayed together as long as it did, is a testament to the overall design in my view. Had our coach not had the fresh water leaks, it would probably still torque up fine. Now, I would have liked to see more beef on the axle side of the bulkhead to keep the bulkhead joint from taking the load from the trailing arms. That wouldn't have saved the coach from the rust damage, but the consequences would not have been as severe. A little bit of PM from the PO would have kept the rust away... :'( Don
It would be interesting to know how the factory does, or did the drilling. Suspect the angle was predrilled, the rest field drilled. Redundancy can make up for derating.
Title: Re: bulkhead blues
Post by: travelite on July 10, 2012, 10:20:59 pm
Hi Don, I whole heartedly agree about more beef in the axle subframes. I've been looking at transit bus chassis for a long time and it's very common to see an axle sub-frame cradle assembly that's self supporting with suspension torque arms attached. Foretravel took a different approach - the Colin Chapman approach. I'd like to see what Foretravel is using today. I know that they've changed their design. Anyone have any info? David
Title: Re: bulkhead blues
Post by: Don & Tys on July 11, 2012, 12:08:48 am
It really is only lacking in one area, and that is where the top of the bulkhead meets the very heavy duty backbone that supports the engine and tranny and has transverse sections which are also very heavy duty which take the full weight of the coach via the air springs. The probelm is that the trailing arms are welded to the bulkhead angle iron and the vertical supports which go up fro there aren't (as far as I can see) attached to that backbone frame, but rather are just out board of it. this (I believe) allows the bulkhead to hinge from the top with nothing but the bulkhead joint and four 2"X1/4" pieces of angle iron welded to the backbone to hold the bulkhead perpendicular to the backbone. Those trailing arms pull on the bulkhead joint every time you use the retarder or exhaust brake. When the joint is comprimised by failed Roloks for whatever reason, those relatively small vertical pieces of angle iron (at least in my case, and in the case of Christies dream apparently) crack right where they are attached to the backbone. It really isn't just one factor, several things have to line up to allow that to happen but in my mind, fixing the bulkhead in a perpendicular alignment to the backbone without relying on the bulkhead joint would make the coach pretty bullet proof. I think that it isn't all that hard to do, and I believe that I have the plan to insure the integrity of that prependicular relationship but I am going to great lengths to insure that the basement framing forward of the bulkhead is up to the task anyway. After all, it may be required to support the weight of 112 gallons of fresh water, 164 gallons of waste, 148 gallons of diesel, maybe 3 8D AGM batteries and all our gear! Don
Hi Don, I whole heartedly agree about more beef in the axle subframes. I've been looking at transit bus chassis for a long time and it's very common to see an axle sub-frame cradle assembly that's self supporting with suspension torque arms attached. Foretravel took took a different approach - the Colin Chapman approach. I'd like to see what Foretravel is using today. I know that they've changed their design. Anyone have any info? David
Title: Re: bulkhead blues
Post by: gam on July 11, 2012, 12:44:46 am
I would like to get a look at a complete set of frame drawings. Gam
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 11, 2012, 09:05:13 am
Some good ideas here, from Don, David and Gam, all excellent points. I would like to, at some point, come to a consensus regarding preferred method of repair for both preventative fixes and repair fixes in cases where a few broken bolts are found. In cases of massive failure Don's fix is, in my mind, the best. The goal is to avoid getting to that point.
If we can agree on an standardized approach then I'd like to focus on the technique of repair and try to come up with a locating/drilling fixture to simplify and precisely locate and drill for the new fasteners. Whether they are bolts or Rolocks it would be an advantage for them to be precisely and uniformly drilled. I'm thinking a fixture that would reference the angle iron with a drill that moves in two axis (Z and X) would be fairly simple to fabricate and use. I will build it, use it on my coach, and pass it along to whoever else needs it. This could also be supplemented by the purchase of a large quantity of the selected fastener, some kind of plugs for the cover panel if the nut approach is taken. A fix in a box, just add labor. I think this is a worthy goal that could benefit the group that prefers to fix their own stuff for whatever reason.
Regarding the 1/4 vs 3/8 Rolocks and the limitations of the 1/8 tubing "nut", seeing as where there are no reports of stripped Rolocks but they are all broken at the shank, might there be an advantage to the 3/8 from a durability standpoint? Being able to drive them into existing holes is appealing, I would think you should be able to back existing Rolocks out without any problem if they are in decent shape. If they are so weak that they snap on withdrawal then you haven't really lost anything. Am I right here, or is it possible that rusty 1/8 tubing could grip a good Rolock hard enough to snap it? Would the additional hole size necessary be a negative vs increased fastener density of 1/4? Karma sent.
Chuck
Title: Re: bulkhead blues
Post by: Roland Begin on July 11, 2012, 09:17:27 am
Quote
I'm no welding expert, but I think it's cause it's bad form to put a weld in bending: Don't Put Welds in Bending (http://weldingdesign.com/blodgett/wdf_10950/). To keep the weld bead (root, toe, and face) out of the compression and tension of bending will require a connection redesign. David
OK That makes sense.
Roland
Title: Re: bulkhead blues
Post by: Paul Smith on July 11, 2012, 09:38:27 am
Right. It's bad form to put a weld in bending.
I made them modify the big 2 tier emergency power battery racks in a nuclear power plant because the angle toe was welded to the post but the angle heel was not. I opined the racks would collapse in an earthquake.
best, paul
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 11, 2012, 10:10:46 am
I made them modify the big 2 tier emergency power battery racks in a nuclear power plant because the angle toe was welded to the post but the angle heel was not. I opined the racks would collapse in an earthquake.
best, paul
Boy, there went your Christmas bottle of Glenlivet from the contractor....
Title: Re: bulkhead blues
Post by: gam on July 11, 2012, 10:25:34 am
Paul They didn't have 87 lbs of documents, 47 welding procedures, and 21 signoffs for fabrication of the racks? Gam
Title: Re: bulkhead blues
Post by: Don & Tys on July 11, 2012, 10:50:39 am
A drilling fixture would be an excellent approach if you don't already have separation in the joint. Since the trailing arms mount to what I am calling shackles that are welded to the angle iron, joint failure leading to separation allows the the bulkhead to to hinge from the top and the angle iron vertical face is no longer parallel to the transverse square tube. So the fixture, while making the hole perpendicular to the angle iron, would insure that the entry hole through the square tubing was not at the same level as the exit hole. That would of course depend on the degree of separation, but in the case of our coach, the angle iron was also bowed with the crown between the two trailing arm shackles. Since I had full access to basement side of the joint and was able to remove the old fasteners, by either double nutting (that worked for about half) or welding a nut to the end, I used the original holes to pull the joint together with through bolts before drilling the couple of extra holes. Don
Some good ideas here, from Don, David and Gam, all excellent points. I would like to, at some point, come to a consensus regarding preferred method of repair for both preventative fixes and repair fixes in cases where a few broken bolts are found. In cases of massive failure Don's fix is, in my mind, the best. The goal is to avoid getting to that point.
If we can agree on an standardized approach then I'd like to focus on the technique of repair and try to come up with a locating/drilling fixture to simplify and precisely locate and drill for the new fasteners. Whether they are bolts or Rolocks it would be an advantage for them to be precisely and uniformly drilled. I'm thinking a fixture that would reference the angle iron with a drill that moves in two axis (Z and X) would be fairly simple to fabricate and use. I will build it, use it on my coach, and pass it along to whoever else needs it. This could also be supplemented by the purchase of a large quantity of the selected fastener, some kind of plugs for the cover panel if the nut approach is taken. A fix in a box, just add labor. I think this is a worthy goal that could benefit the group that prefers to fix their own stuff for whatever reason.
Regarding the 1/4 vs 3/8 Rolocks and the limitations of the 1/8 tubing "nut", seeing as where there are no reports of stripped Rolocks but they are all broken at the shank, might there be an advantage to the 3/8 from a durability standpoint? Being able to drive them into existing holes is appealing, I would think you should be able to back existing Rolocks out without any problem if they are in decent shape. If they are so weak that they snap on withdrawal then you haven't really lost anything. Am I right here, or is it possible that rusty 1/8 tubing could grip a good Rolock hard enough to snap it? Would the additional hole size necessary be a negative vs increased fastener density of 1/4? Karma sent.
Chuck
Title: Re: bulkhead blues
Post by: gam on July 11, 2012, 12:18:04 pm
If during fabrication the 5/16" holes were drilled in the angle iron on a drill press. then that part was aligned to the box tubing frame and the pilot holes for the Roloks where drilled by hand,any angular miss alignment of the holes would cause a bending moment in the Rolok when it was torqued. A screw with a high tensile strength like a Rolok is brittle and with more load under one side of its head then the other ,and repeated loading and unloading (like with the retarder) will tend to fracture just past the first bolted member. If someone can send me a broken Rolok I will try and have it looked at by a Metallurgist.Gam
Title: Re: bulkhead blues
Post by: Paul Smith on July 11, 2012, 12:54:37 pm
Don't know. Our walk down was a result of a TMI issue. TMI identified they did not have paper certifying the environmental qualification of equipment. And failure of equipment in a steam environment was a factor in the accident. Billions was spent replacing equipment.
It was then noticed that paper demonstrating earthquake qualification was lacking.
We developed specific walk down procedures for each type of equipment based on the performance of equipment in past earthquakes - such as the 1985 magnitude 8 earthquake in Chile that I did the initial rapid survey on. A later team performed the detailed survey.
This was for the 40 or so oldest nuclear power plants.
Best, paul
Quote
Paul They didn't have 87 lbs of documents, 47 welding procedures, and 21 signoffs for fabrication of the racks? Gam
joseph gambaro 1999 U295 36'
Title: Re: bulkhead blues
Post by: gam on July 11, 2012, 01:30:03 pm
Paul I worked some at Enrico Fermi #1 for DTE in 1965. The plant that all most blew up Detroit (what a joke). Later on I worked as a mechanical and piping inspector for DTE on a project with Bechtel as the general contractor. They can generate more paper work then the NRC !!! GAm
Title: Re: bulkhead blues
Post by: travelite on July 11, 2012, 03:10:25 pm
If someone can send me a broken Rolok I will try and have it looked at by a Metallurgist.Gam
That'd be great Gam. The broken ones tend to be very rusty but they may still tell a story. If anyone removes any unbroken bolts maybe they too can be forwarded to Gam. Unbroken bolts may offer clues as to the start of failure. Another piece of the puzzle. David
Title: Re: bulkhead blues
Post by: travelite on July 11, 2012, 08:10:09 pm
Just sitting here daydreaming about bulkheads and I'm thinking is there anyway to get to the inside of the 1 1/2" box section? We're talking jigs to help place and drill holes precisely, but the 1/8" nut seems to be a perennial problem. What if we took an 8' length of steel flat bar or maybe two 4' sections, say 1"x3/8". We could drill and tap holes every so many inches using the same jig that drills holes into the 1/4" angle section. Each hole in the flat bar could then be tapped. The question is... Is there any way to get to the side of the box section to slide these flat bar sections inside of it? David
Title: Re: bulkhead blues
Post by: wolfe10 on July 11, 2012, 08:14:46 pm
David,
Were you to remove fiberglass to access the box beam, you could just as easily use large rectangular washers and nuts.
The rectangular washers could easily be made from 1/8" or 1/4" steel: 4-6" long by 1 1/2" tall. Much easier to align and would give the same clamping force you are suggesting.
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 11, 2012, 09:26:56 pm
The tapped 1/4" flat bar scheme inside a square tube was used to secure a precision rail on the Y axis of a CNC table I built. I was not impressed with it, suspect that the rolled threads produced by a Rollock in 1/8 tube have more strength than tapped 1/4 bar. Could be I'm a lousy bolt tapper but there just didn't seem to be enough meat there.
The idea of using a larger quantity of Rollocks is appealing for a couple reasons:
Ease of installation-no cutting of body panel, no foam removal, no patching.
Quick to install, especially with some type of alignment jig.
Can possibly be upsized a bit in dia. Increased fastener density no problem.
That said, there are reports from Brett and others indicating good service and no failure from bolted connections. I think if you have separation in the joint, that level of failure, that bolts and backing plates would be the way to go due to alignment issues that have been pointed out. No reason you couldn't add a few extra of these either.
This will be preventative maintenance for me, no sign of bulkhead separation. The Rolocks, in this case will be a simpler installation.
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 11, 2012, 09:40:14 pm
Just sitting here daydreaming about bulkheads and I'm thinking is there anyway to get to the inside of the 1 1/2" box section? We're talking jigs to help place and drill holes precisely, but the 1/8" nut seems to be a perennial problem. What if we took an 8' length of steel flat bar or maybe two 4' sections, say 1"x3/8". We could drill and tap holes every so many inches using the same jig that drills holes into the 1/4" angle section. Each hole in the flat bar could then be tapped. The question is... Is there any way to get to the side of the box section to slide these flat bar sections inside of it? David
David,
That very same thought came to me yesterday. The compartment can be opened, the white curved plastic/fiberglas can be carefully sectioned about 3 inches and then there is easy access to the 1 1/2" square tubing. I was thinking of a 1" wide flat bar, either full length or half length. It could be 5/16" or so in thickness with grade 8 nuts tacked to the far side or 1/2" and just tapped.
I was under my U300 today and was able to unscrew the last Rolock nearest the curb. There is no evidence of any rust inside the tubing as the threads are very clean except where the back of the angle iron and the bulkhead meet along with a small amount where the Rolock enters the sistered 16 gauge tubing. The failures seem to be on the outside of the tubing and it apparently very dry inside the main tube as the broken Rolocks seal the water out.
The big surprise was when I removed one Rolock in the middle of the failed field of 6. I used a long torque wrench and attempted to remove it. After applying considerable pressure, the Rolock failed with a big bang shooting the bolt head out of the torque wrench and about 20 feet away. Before this attempt, I had a gap of about a hacksaw blade thickness for several inches. Suddenly, I have a quarter inch gap for 18 inches. This could explain the sudden failure experienced last month by a member.
The other problem in inserting a bar is the Rolocks that have broken off. They are still inside and unless they can be removed, I can't see a way to get past them. A long sawsall blade could catch the first foot or so but after that if the others fail, it would be difficult.
In looking at Don's photos, the ends at each side have the 16 gauge square tubing sistered on so any bolt, even with a flat plate 5 inches long, could not be tightened to recommended torque, certainly not a grade 8. Since all of my failures are behind the double tubes, this makes the repair a little on the edge.
After today, I would say that in checking the condition of your Rolocks, the bolt head should be loosened at least a turn before tightening to the torque spec. This is the only way to check if it is on the verge of failure. Pulling it out and checking for rust 1/4" in from the head will give the best indication of it's condition.
Here is the good one I pulled.
Pierce
Title: Re: bulkhead blues
Post by: Don & Tys on July 11, 2012, 09:56:58 pm
I considered this option, but in my case, I was unsure that the 1/8" square tubing might be too thinned out so that the wall of the tubing might fail if it was all that was holding the joint together. Also the precision necessary would be very challenging. To get at the open part of the bulkhead transverse tubing, you would need to remove the bottom extruded aluminum trim piece whereupon you will find that there is a 1.5"X1.5"X1/8" angle iron that runs the full length on both sides of the coach (except where the sewer etc. connections exit on the unicoaches) capping off the end of both front and back transverse bulkhead tubes. I replaced that piece as well as the longitudinal outer most square tubes (and many others), so I had full access to do something like this. Besides my concern for the wall thickness, there was one Rolok that I couldn't get out because it basically came through right at the junction of one of the longitudinal frame members. It was about in the middle, so I would have had to have found a way to bust it out somehow. I also considered inserting another piece of smaller square tubing inside the 1.5" transverse piece to reinforce the whole tube, but that had its own problems ( I.e., the seam present inside cold rolled steel tubing). Ultimately, I felt that doubling up all the way across and adding diagonal sections was the way to go because my utility compartment was completely gutted and I had unfettered access to all sides of the framing. By the way, the inside of the the inch and a half tube is 1.25" across, irrespective of the seam.
I had saved this a draft and see that Pierce has already talked about the broken Roloks inside the tube...LOL! Oh well, I may as well post it as is incase there is some bit that might help someone down the line... Pierce, on the Unicaoch, that outer trim piece is extruded aluminum maybe it is on yours as well. I did have a challenge getting some the screws that hold that in (several were broken already and a few others broke when I tried to remove them). Anyway, to access the end of the tube, you would need to cut the part of the eighth inch thick angle iron that runs on the outside of the framing that covers the end of the tube. That could potentially weaken it a bit. For what it's worth... Don
Just sitting here daydreaming about bulkheads and I'm thinking is there anyway to get to the inside of the 1 1/2" box section? We're talking jigs to help place and drill holes precisely, but the 1/8" nut seems to be a perennial problem. What if we took an 8' length of steel flat bar or maybe two 4' sections, say 1"x3/8". We could drill and tap holes every so many inches using the same jig that drills holes into the 1/4" angle section. Each hole in the flat bar could then be tapped. The question is... Is there any way to get to the side of the box section to slide these flat bar sections inside of it? David
Title: Re: bulkhead blues
Post by: gam on July 11, 2012, 10:03:48 pm
Pierce. It sounds like you tried to remove the only one in that area that was holding the load for the broken ones. But the thing is the thread for that one with even that much load on it hadn't stripped or pulled out. It is looking to me like the real problem is how they where installed . Pilot hole not aligned with the 5/16" hole drilled in the frame. The fix could be as ez as a two piece spherical washer under the roloks head.Gam
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 11, 2012, 10:19:14 pm
Pierce,
In looking at the area where the heads of the broken ones were, can you see any indication that they were installed out of square to the material? Indications are that one Rollock was strong enough to do the job of 6 but several failed on either side of it with no rust problems. Hard to imagine an applied force that would do this.
It sure sounds like Gam's idea of misalignment is what is at work here. Pilot drill first then clearance drill, and keep it square. We all know that, right?
Chuck
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 12, 2012, 12:32:02 am
The Rolock in the photo was at the far outside, away from the direct spray from the wheels. The others show a lot more rust. It is apparent some rust jacking has taken place. Perhaps rust jacking as well as loss of strength from the rust may have been the culprit. So far, I have not seen any misalignment but have only remove the one pictured. The sudden failure of the one being removed seemed to be related to severe rusting in the threads next to the break in the 1 1/2" square tubing. It did not move a degree before suddenly failing. The head did show a great deal of rust at the 1/4" mark. Suspect this is the distance where rust jacking could have caused the failures in the others.
The front bulkhead has one more failed Rolock than the rear in exactly the same spot, directly where the front tire sprayed water on them. I can't help thinking this is more than a coincidence.
Can't rule out completely that the holes were drilled without a jig and misaligned but it seems unlikely judging by the quality of welds, and general quality workmanship seen underneath. The small locking ridges on the Rolocks as well as lack of any sealing or rust protection may be a factor in allowing water in. Some may have drained down between the angle iron and the bulkhead or wicked up. The rear tires throw most of the water back but enough is left in the tread to soak the area in the rain. The front bulkhead angle iron gets a constant stream on it from the tire in the rain. Could be the reason more failed up front.
Pierce
Title: Re: bulkhead blues
Post by: Neal Pillsbury on July 12, 2012, 01:00:26 am
Talk about going viral! Over 2100 hits in less than nine days?
Periodically new bulkhead participants stroke the alarm bells and create new theories and tangents to the bulkhead issue. It's always possible (in making mountains out of molehills?) to lose sight of what is important to the general Foretravel population!
We could certainly make the well documented bulkhead issue into something weird enough to COMPLETELY scare away ALL potential future Foretravel buyers and cause ALL current owners to suffer irreparable sleep deprivation. OR, we could logically, review the body of evidence and reasonably conclude that we have 99% or more of the information that we need to be perfectly comfortable.
SPECIFICALLY: 1. The bulkhead issue is easy to detect, should logically be a part of any pre-purchase body of wisdom, and routine inspection (250 in-lb. torque with a qualified tool) must be a part of each UNIHOME/UNICOACH owner's ongoing periodic maintenance/inspections.
2. We have heard from Foretravel, and their guidance is reasonable and perfectly understandable. Bulkhead Separation (http://www.foreforums.com/index.php?topic=10625.msg50449#msg50449) Can we or should we reasonably expect any more?
What's ROOT CAUSE IMPORTANT? We know that: a. moisture/water aggravates the issue, b. chlorides in the form of (from most to least severe) liquid deicers, rock salt and salt air aggravate the issue. c. dissimilar metals aggravate the issue (galvanic cell corrosion) d. Any coaches ever operated north of I-20 are automatically suspect and bear closer inspection/watching, especially if they were operated there between the months of October and May. Corrosion Article (https://www.foreforums.com/index.php?action=dlattach;topic=10625.0;attach=1179) e. If iron oxide (rust swelling) is present in the joint, the loose iron oxide must be removed and the surface area must be neutralized (eg. with phosphoric acid to turn the red iron oxide to black iron oxide (stable). This stops the oxidation, preserving and protecting the area prior to undercoating or otherwise protecting the bulkhead joint.
3. Then, thanks to Brett Wolfe's experience and wisdom, we know that once a bulkhead fastener failure is detected, there exists a comprehensive, tried and proven set of guidance on how to address the failure. Bulkhead Separation (http://www.foreforums.com/index.php?topic=10625.msg50296#msg50296) Owners that have done so (or have had FOT, MOT or Xtreme address the bulkheads) have peace of mind and VERY SOUND COACHES.
It isn't any more daunting than that and the bulkhead design should be a strong Foretravel selling point instead of the negative mystery that seems to be pursued in repeating, cyclical fashion. The Foreforums search feature yields a tremendous wealth of knowledge on the bulkhead issue (as well as speculation). Barry Beam's information condenses the vast wealth of FT knowledge into an easily searchable form that weeds out much of the chaff.
But reinventing the issue every few months doesn't create any improvement in the root cause understanding nor the action plan to address the presence of the issue. As Brett has said, "It wasn't a fun project, but neither was it mechanically challenging nor expensive." I would contend that it was a fun (DIY) project (for me), the repair has been easy to periodically re inspect and the repair has been perfectly stable since 2009.
Just my perspective, and I'm sure that it will not be universal, but I hope that this helps to tone down the severity of the alarm that is being created.
Neal
Title: Re: bulkhead blues
Post by: gam on July 12, 2012, 01:01:32 am
One more thought . When the screw you where trying to remove failed under load the head shot out like a rocket. But for most of the failed screws the heads where still in there holes . So they didn't fail under load? The screw head just snapped off? Its 1AM and I can't sleep. Gam
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 12, 2012, 01:18:03 am
Expect they failed one by one so the angle iron did not move more than a few thousands of an inch each time. They stayed in place probably because they had a lot of rust. I had to pry some out of the angle iron with a screwdriver. When the last one popped, there were no others left so the angle iron jumped out. It was in the middle of the failed fasteners. I can now imagine what the highway failure must have been like last month.
10pm here. Just finished an old episode of Falcon Crest.
Pierce
Title: Re: bulkhead blues
Post by: Peter & Beth on July 12, 2012, 07:53:51 am
Thanks Neil...sure seems it is time to put this topic to rest...Couldn't find the one before on bulkhead seperation, but believe it had thousand of hits also...
Yes!!!
However, the new owners and foreforums members will want to seek advice and information about their rig's issues on this topic. I think it should be readily available to all new & prospective owners/members. Just my thought on this as I have taken the advice given and had Forrest repaired at Xtreme. Peter
Title: Re: bulkhead blues
Post by: Michelle on July 12, 2012, 08:20:10 am
Thanks Neil...sure seems it is time to put this topic to rest...Couldn't find the one before on bulkhead seperation, but believe it had thousand of hits also...
It's one of the sticky topics at the top of this board (Tech Talk) Bulkhead Repair-- A Comprehensive Look (http://www.foreforums.com/index.php?topic=8645.0)
And thanks Neal. Karma to you!
Michelle
Title: Re: bulkhead blues
Post by: Tim Fiedler on July 12, 2012, 08:23:30 am
Neal,
Thanks, perfect summary. Hope this quells All the recent noise.
Title: Re: bulkhead blues
Post by: wolfe10 on July 12, 2012, 10:15:42 am
Talk about going viral! Over 2100 hits in less than nine days? Periodically new bulkhead participants stroke the alarm bells and create new theories and tangents to the bulkhead issue. It's always possible (in making mountains out of molehills?) to lose sight of what is important to the general Foretravel population! We could certainly make the well documented bulkhead issue into something weird enough to COMPLETELY scare away ALL potential future Foretravel buyers and cause ALL current owners to suffer irreparable sleep deprivation. OR, we could logically, review the body of evidence and reasonably conclude that we have 99% or more of the information that we need to be perfectly comfortable. SPECIFICALLY: 1. The bulkhead issue is easy to detect, should logically be a part of any pre-purchase body of wisdom, and that routine inspection (250 in-lb. torque with a qualified tool) must be a part of each UNIHOME/UNICOACH owner's ongoing periodic maintenance inspection. 2. We have heard from Foretravel, and their guidance is reasonable and perfectly understandable. Bulkhead Separation (http://www.foreforums.com/index.php?topic=10625.msg50449#msg50449) Can we or should we reasonably expect any more? What's ROOT CAUSE IMPORTANT? We know that: a. moisture/water aggravates the issue, b. chlorides in the form of (from most to least severe) liquid deicers, rock salt and salt air aggravate the issue. c. That dissimilar metals aggravate the issue (galvanic corrosion) d. Any coaches ever operated north of I-20 are automatically suspect and bear closer inspection/watching, especially if they were operated there between the months of October and May. http://www.foreforums.com/index.php?action=dlattach;topic=10625.0;attach=1179 (http://www.foreforums.com/index.php?action=dlattach;topic=10625.0;attach=1179) e. If iron oxide (rust swelling) is present in the joint, the loose iron oxide must be removed and the surface area must be neutralized (eg. with phosphoric acid to turn the red iron oxide to black iron oxide (stable). This stops the oxidation, preserving and protecting the area prior to undercoating or otherwise protecting the bulkhead joint. 4. Then, thanks to Brett Wolfe's experience and wisdom, we know that once a bulkhead fastener failure is detected, there exists a comprehensive, tried and proven set of guidance on how to address the failure. Bulkhead Separation (http://www.foreforums.com/index.php?topic=10625.msg50296#msg50296) Owners that have done so (or have had FOT, MOT or Xtreme address the bulkheads) have peace of mind and VERY SOUND COACHES.
It isn't any more daunting than that and the bulkhead design should be a strong Foretravel selling point instead of the negative mystery that seems to be pursued in repeating, cyclical fashion. The Foreforums search feature yields a tremendous wealth of knowledge on the bulkhead issue (as well as speculation). Barry Beam's information condenses the vast wealth of FT knowledge into an easily searchable form that weeds out much of the chaff. But reinventing the issue every few months doesn't create any improvement in the root cause understanding nor the action plan to address the presence of the issue. As Brett has said, "It wasn't a fun project, but neither was it mechanically challenging nor expensive." I would contend that it was a fun (DIY) project (for me), the repair has been easy to periodically re inspect and the repair has been perfectly stable since 2009. Just my perspective, and I'm sure that it will not be universal, but I hope that this helps to tone down the severity of the alarm that is being created. Neal
Very well said, Neal.
Brett
Title: Re: bulkhead blues
Post by: Don & Tys on July 12, 2012, 10:21:58 am
Surely there are many here in the forum who have heard more than enough about this topic. There is always the option to skip over it... My take on it is that there are some of us currently in throes of dealing with this very issue that find the topic to be of intense interest! The extent of bulkhead problem on our coach was as bad or worse than any I have heard about, and although I read posts on the topic before we bought the coach (including Brett's sticky post), none of them prepared me for what was to come. I am finally approaching the other side of this tunnel, and although it has been satisfying in some ways to try and meet the challenge with our limited resources, it hasn't been what I would call a fun ride. In spite of that, I remain happy with our having chosen a Foretravel to be our future fulltiming home. When we bought it, I never thought our fulltiming future would be quite so far in the future and that I would long ago have finished the work on my house and sold it. It hasn't happened that way... In the mean time I have been learning the ins and out of our coach from the bottom up, and I mean that litterally! So to those that have faced the issue and successfully dealt with it, I congratulate you on a job well done! For those that are facing the issue now, please feel free to ask your questions and or share what you have learned. For those that haven't had to face the issue, listen to the preventative maintenance wisdom so ably presented by Brett, Neal, and others so that you don't have deal with the harsher reality that neglect inevitably brings. Finally, for those who grow tired of hearing about it, I can understand that as well but it is easy enough to pass by the topic. I don't think my purpose has ever been to cause alarm or declare that the sky is falling. Sure, when I discovered our bulkhead separation, I was unhappy... unhappy with myself for not educating myself to the point where I could recognize the issue and at least use the information so I could bargain more effectively. What I had read about the process of repairing the area lead me to believe that even if there was an issue, It would just be a bump in the road. The conventional wisdom didn't seem to apply to our coach, as it had been in Texas all of its life and not apparently operated in areas where it was subject to deicing chemicals and other environment insults. The conventional fixes would have been a band aid at best. There are so many good things about Foretravel coaches and this issue is but one negative that good information can neutralize completely. I for one encourage anyone with information or experience about this issue to post it, as long as it is done as respectfully and as informatively as possible. I can't tell you how great a resource this forum has been to me as I have progressed through this process. Sometimes the exchange of ideas and even speculation as to possible causes and effects have helped me think things through and saved me from making (more) mistakes. Maybe I am being alarmist here, but I think a call to put this topic to rest amounts to applying the "retarder" on the free flow of information and just getting to know people (at least one aspect of them) here in this virtual world. I hope I haven't ruffled anybodies feathers by sharing how I feel about this, but I have been living and breathing (again literally!) this issue for the best part of year now. I am sure that there are many who think I care about nothing else, but I really, sincerely, and passionately look toward more fun stuff! After all, that is why we bought this coach in the first place! Don
Title: Re: bulkhead blues
Post by: jor on July 12, 2012, 10:55:27 am
Don, keep posting. What I really like about your posts is they aren't just simply an intellectual exercise; they are the real deal. Your work progress reports and photos allow us to see deeply into these rigs. Stay with it. You'll be on the road soon! jor
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 12, 2012, 11:09:48 am
Well said Don. I also believe that the collective experience of others, not necessarily specific to motorhomes, can lead to innovative preventative maintenance and repair solutions.
Most folks want straightforward, standard solutions to problems and are not interested in knowing what's happening on a micro mechanical or molecular level. For those, a standard documented fix and theory of causation is available as referenced many, many times.
By the same token, there's no call for the proponents of the above fix to be offended when alternate methods are discussed. This discussion has not been "noise, invention or fluff" to me. The fact that the term "it's not if but when" has been used a number of times in reference to this issue makes me believe the search for a simple preventative fix is proper.
Fact is, I believe that Foretravel is a fabulously well built and designed coach, and this typically minor issue pales in comparison to the problems most coach of this vintage suffer.
Chuck
Title: Re: bulkhead blues
Post by: P. Wyatt Sabourin on July 12, 2012, 11:26:32 am
I really appreciate all this information on "the bulkhead issue". In the fall of 2009 I inspected a Foretravel and because of this forum, I examined the bulkheads carefully. Rust jacking was very evident and so I did not purchase that particular Foretravel. At that time this Forum was boiling over with negative bulkhead posts.
I decided to NOT purchase a Foretravel and looked for SOBs for a few months but soon realized that all SOB motorhomes have issues which are far worse then the bulkhead issue. At the same time, the negative bulkhead posts were replaced by more realistic bulkhead posts.
I purchased a Foretravel in April of 2010 after examining the bulkheads which had minor surface rust. Later, torque testing bulkhead bolts caused the three heads on the outside passenger side rear to fall off. The three bolts on the outside passenger side hold nothing, and yet, the bulkhead remains tight. Foretravel motohomes are finesse engineered and they work well.
After two years of ownership, I love this coach and this Forum.
Thanks Neal for your positive post on this bulkhead issue which in my opinion is a minor issue (not a problem).
Title: Re: bulkhead blues
Post by: John Haygarth on July 12, 2012, 01:11:12 pm
adding to this list of "happy Foretravellers" regardless of this problem, my coach was a Calif' one and now is going all over the place and living in the "Great white-cold North" and passing over many miles of snow-ice and wet on trips south. So, that said mine should be one of the ones affected soon, but see no evidence of rust or jacking. When I bought it and had it in Mexico for first time I had a Mexican friend of ours crawl under and wire brush the angle and joints as I had a feeling that it had better be sealed off from road crap etc thrown up by tires. He then sprayed (which I allways take with me) a couple cans of the underseal Bitumin all over those areas. Little did I know when joining this Forum a few months later that this was a main topic!! I have not tried to Torque the bolts yet but will as soon as it cools down here, just to be sure all is ok. If they are bad (which I doubt) Peirce had better finish his job quick as I will be renting his "new Pit" to fix mine. John H
Title: Re: bulkhead blues
Post by: Dwayne on July 12, 2012, 02:37:48 pm
I know if I keep my coach long-term I'm going to have to address the suspension issues (removed last of the rear shims last year) so my plan is to watch the bolts and perhaps make a pilgrimage to Nac and have the new springs installed and have the bulkheads reinforced at that time. I hate the idea of spending 25% of the value of the coach on these two issues but since it's paid for it will be cheaper to keep this one up than trading up. Might even have the bath remodeled as I hate that 3 foot step up into that tub.
Title: Re: bulkhead blues
Post by: jor on July 12, 2012, 06:38:30 pm
Quote
make a pilgrimage to Nac and have the new springs installed and have the bulkheads reinforced at that time. I hate the idea of spending 25% of the value of the coach on
Dwayne, on our 225, after setting the ride height, I was down to one shim so essentially the same boat your in. The problem is that the Torsilastic is no longer readily available. Some guy whose name escapes me right now (acquaintance of BrettW?) bought all of them that we're available a few years back. I talked to him and I think it was around five grand for a set. However, I'm thinking that once you have the height set correctly you shouldn't have to worry about removing shims for years. That's the way I was looking at it anyhow. jor
Title: Re: bulkhead blues
Post by: Dwayne on July 12, 2012, 07:54:48 pm
Quote
This post applies only to Safari and Foretravel coaches with the B.F Goodrich Torsilastic Suspension
GREAT news. Navistar, in buying out Monaco/Safari, came across a warehouse with a number of original equipment B.F. Goodrich Torsilastic parts.
Ralph Andrews who owns a Safari coach with torsilastic suspension and is very familiar with this suspension on the Safari products bought the whole lot. He owns Pioneer Metals: Pioneer Metal Works (http://www.pioneermetalworks.com/)
I've had several people tell me that it would be cheaper to fabricate some bases for air bag supplementation for the existing springs. I haven't totally given up on that idea yet.
Title: Re: bulkhead blues
Post by: Felix and Gail on July 12, 2012, 09:07:00 pm
John Haygarth, you had mentioned a deflector for preventing overflow from the water tank to the bulkhead. Could you elaborate on how this is done.
Title: Re: bulkhead blues
Post by: Rudy on July 12, 2012, 09:16:32 pm
Felix,
I took the hint from Barry of Barry & Cindy. I pulled the overflow hose loose from the bulkhead fitting, inserted a 90 degree elbow, attached an additional hose and routed the overflow down the passenger side of the freshwater tank through the floor on to the ground. This completely bypasses getting water on the bulkhead.
Thanks again, Barry
Title: Re: bulkhead blues
Post by: Felix and Gail on July 12, 2012, 09:25:17 pm
Rudy , is there any problems drilling through the floor and did you use a hole saw? The floor appears to be fairly thick. I was trying to avoid drilling through the floor if possible.
Title: Re: bulkhead blues
Post by: wolfe10 on July 12, 2012, 09:43:36 pm
Rudy , is there any problems drilling through the floor and did you use a hole saw? The floor appears to be fairly thick. I was trying to avoid drilling through the floor if possible.
The floor of the basement is a sandwich: thin layer of fiberglass, foam core, thin layer of fiberglass. Yes, there are steel beams in the floor, so use a magnet to make sure you know where they are (and are NOT).
Very easy to drill with a hole saw.
Brett
Title: Re: bulkhead blues
Post by: Rudy on July 12, 2012, 09:46:56 pm
Felix,
I used a paddle bit (inch and a half I think) and drilled the floor, foam insulation and the outer skin. I used 3-M 4200 to seal around the tube at the floor and at the underside skin.
I had to remove the grey carpet panel and placed the hole between the panel and the tank. With the panel re-installed, one can not see the change. Took 30 minutes because I went between the steel frames as suggested by Brett.
Hope this helps.
Title: Re: bulkhead blues
Post by: Felix and Gail on July 12, 2012, 09:56:02 pm
Rudy, Thanks, I will look into that solution.
Title: Re: bulkhead blues
Post by: jor on July 13, 2012, 09:38:06 am
Quote
From the incredible Mr. Beam: Torsilastic Suspension Parts
Hey, that's great news that they are still available. Thanks. jor
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 13, 2012, 05:34:41 pm
I've had several people tell me that it would be cheaper to fabricate some bases for air bag supplementation for the existing springs. I haven't totally given up on that idea yet.
I bought a supplemental set of Firestone air bags for my old SOB off Craigslist for $50. Was easy to install and made the handling much better. They have not lost any pressure since I put them on. The rear had started to sag but a few PSI brought I back to stock height.
Pierce
Title: Re: bulkhead blues
Post by: Dwayne on July 13, 2012, 05:37:57 pm
Took the torque wrench when I went to remove the alternator and even though I didn't have time to check all of them, I did check as many as I could reach from either side (4-5). The second one in on the left front and another one three or four further in on the left front are broken. So out of 16-20 tested two are broken and the driver's side front seem to be the bad area. The joint looks fine. I suspect they were broken on installation. I don't see any sign of fresh water tank leaking as it is the only tank in the area but it is in the center. Has anyone tried any of the reverse drill bits to get a bite on the broken bolt to extract it? If I only have two or three, I'd like to remove and replace. I'm going to check them all this weekend.
Title: Re: bulkhead blues
Post by: Dwayne on July 13, 2012, 05:41:06 pm
Pierce: you are talking about a coach that already had airbags right? Fabricating airbags over the torsilastic spring is going to be an interesting project. James Triana told me that he'd heard it has been done but didn't have details.
Title: Re: bulkhead blues
Post by: wolfe10 on July 13, 2012, 05:41:57 pm
Dwayne,
They are grade 8, so would not even try to drill from the "outside". The easy way is to drill the access hole through the fiberglass (be sure to have the hole saw appropriate for the plug you will install. Then, after soaking in penetrating oil, double nut and screw the remainder of the bolt toward the "center of the coach".
Brett
Title: Re: bulkhead blues
Post by: Felix and Gail on July 13, 2012, 07:43:43 pm
I decided to use the ARP stainless steel as per Dons technique and remone the 304 SS as I do not like to use any thing that will possible rust in that area. I had 8 bolts that fell out after applying 20 ft lbs. of torque. I am awaiting the arrival of the ARP SS boltls from summit. They are claimed to exceed grade 8. I did not have any significant separation, only the bolt head that came lose after very little torque, much less than 20 ft #. sorry I do not have an inch # torque wrench. Fortunately I used .o20 aluminum to cover the acess holes, so it can be easily removed.
Title: Re: bulkhead blues
Post by: Jimmy Freytag on July 13, 2012, 07:45:02 pm
I've had several people tell me that it would be cheaper to fabricate some bases for air bag supplementation for the existing springs. I haven't totally given up on that idea yet.
Dwayne, there was a U240 36ft that was traded in at MOT by a retired Marine from Louisiana in the fall of 2010 that he had put air bags on the rear. Might to to some one at MOT that might remember it
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 13, 2012, 08:09:05 pm
Pierce: you are talking about a coach that already had airbags right? Fabricating airbags over the torsilastic spring is going to be an interesting project. James Triana told me that he'd heard it has been done but didn't have details.
No, I installed it on a 26 footer with big leaf springs. They had flattened out over time. The ride was so soft, everyone on board got sea sick.
No idea what your suspension looks like or how feasible the installation is. With the airbags, you can adjust the pressure to control height and firmness. Some owners have installed an air regulator to adjust while driving. Mine installation was the rear only. They were only about one third to one half the size of the Foretravel airbags. They had generic mounts on each end that I modified for my installation.
Pierce
Title: Re: bulkhead blues
Post by: Dwayne on July 14, 2012, 02:34:16 pm
Inspected every bolt today. 3 total are broken. The second one in on the left front and the second one in on the right rear and the sixth one in on the left front. I am going to remove them and order some new roloks. I really don't want to drill for larger through bolts. Some spray foam and an aluminum cover siliconed on should do for quite a while.
Title: Re: bulkhead blues
Post by: Felix and Gail on July 15, 2012, 05:15:55 pm
Successfully diverted fresh water overflow through bottom of bay. Went just left of water manifold and next to black water tank. there weren't too many choices due to metal beams detected with a magnet. Thanks to Rudy and Brett Wolfe for the suggestions. Actually there were the thin fiberglass skins and a thick layer of plywood that I had to drill through.
Title: Re: bulkhead blues
Post by: John Haygarth on July 15, 2012, 06:04:13 pm
Question to all the experts on this saga-- If the concensus is that the Retarder is the culprit (mainly, and not rust jacking) for the rear Bulkhead, what causes the front one to have same problem? Fast take offs in reverse?? Am I missing something/ I believe the rust problem more than Retarder as I have used mine a LOT over the years and I do not have 1 bolt broken. Another thought, would it be of interest for one of the moderators to make a table that we can add our info to see which models and years are most affected. Say yr/length/and engine size. My thought is there are more 40ft units with the problem than say 36'. Just a thought. John H
Title: Re: bulkhead blues
Post by: Felix and Gail on July 15, 2012, 06:14:33 pm
My front bulkhead is perfect. Had 8 bolts rear bulkhead that came off with much less than 20 ft lbs of torque. Very minimal separation rear and none in front. No explanation except for water intrusion rear bulkhead. Bolts that sheared off were on both ends. middle bolts were good.
Title: Re: bulkhead blues
Post by: Dwayne on July 15, 2012, 06:42:12 pm
I'm no engineer and although water is always a problem with steel, I have to think that unanticipated forces on this junction is a major part of it. I think they were thinking in two dimensions: push/pull and up/down. When the coach is going over bumps or turning there is probably some twisting or lifting force on one side of the connection and downward force simultaneously on the opposite side. If not exactly this, something like it. As with anything, it is always when several things come together at the same time that causes failure (perfect storm). Poor design + water intrusion through the larger hole in the angle iron + fresh water being dumped across from above + road salts + unsealed union. I'll bet if they'd have just put something gummy like undercoating between the angle iron and box beam before roloking it up it might have prevented the problem.
Title: Re: bulkhead blues
Post by: Don & Tys on July 15, 2012, 07:10:17 pm
John While not claiming to be an expert on the matter, I am at least someone who has spent many hours contemplating the subject (many of those hours camped underneath!), I do have some ideas about it. I don't think that the retarder is the main cause, but it is perhaps the strongest force directly acting to separate the joint. The front bulkhead on our coach has just one broken bolt and that one is the outer most on the curb side. I removed all of them and wire brushed them for close inspection (one at a time of course... there has to be something to hold up the 1/3 tank of diesel!) It is broken off about an inch and a quarter in, or right before it goes into the back wall of the square tube. Moisture is definitely implicated since all of the Styrofoam in that area was pretty well eaten up by diesel exposure, creating an opportunity for condensing moisture.
I firmly believe that the retarder, and to a lesser extent on the older coaches, exhaust brakes are just a contributing factor and perhaps one of the more dynamic forces acting on the joints because of the trailing arm connection from the drive axle, which isn't a factor on the front bulkhead. I can imagine that more of the northern and eastern coaches that travel the winter roads are more prone to front bulkhead failure from exposure because of the pretty direct exposure to water etc. coming right off of the front tires. Our coach has virtually no rust on any of the exposed frame work front or rear, just plenty of dirt... LOL. Just my one cent... I would give two, but I am trying to pay the mortgage! Don
Question to all the experts on this saga-- If the concensus is that the Retarder is the culprit (mainly, and not rust jacking) for the rear Bulkhead, what causes the front one to have same problem? Fast take offs in reverse?? Am I missing something/ I believe the rust problem more than Retarder as I have used mine a LOT over the years and I do not have 1 bolt broken. Another thought, would it be of interest for one of the moderators to make a table that we can add our info to see which models and years are most affected. Say yr/length/and engine size. My thought is there are more 40ft units with the problem than say 36'. Just a thought. John H
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 15, 2012, 07:14:45 pm
Nothing to do with retarder, jake, towing, or fast acceleration/braking. Rust jacking from water intrusion and lack of rust preventative coatings like galvanizing, etc. is the cause for Rolock failure in my opinion with plenty of strength in the factory structure if the fasteners have not been compromised and only after they have been, do the retarder, jake, towing or anything else come into play. Rust proofing, diesel resistive foam, no plywood, drains, etc. could also have been used in the center section and would have prevented Don and Tys damage.
Not a vehicle out there on the road that does not have a problem area(s). Most SOBs have so many issues that forum posts must take an hour to read each day. So much is good with our coaches, we just have to deal with it and make sure it is on the list of preventative maintenance items. And it is such an easy thing to check.
I am a not a believer in sweeping this under the carpet but rather keeping this active as members encounter bulkhead issues. It has been around two months since a forum member had a major problem. If keeping this topic occasionally in the forum posts can keep future and present owners aware and prevent another occurrence, great. I know this is an old, boring topic for a lot of us but not so if you are a new owner.
Pierce
Title: Re: bulkhead blues
Post by: Dwayne on July 15, 2012, 08:34:42 pm
Is every rolok accessible by drilling the hole through the fiberglass bottom...even those first two or three at the street and curbside? I can't tell from Don's great photos if there is a box beam perpendicular to the bulkhead on the sides and perhaps at very points across that will interfere with accessing the roloks at those locations.
Title: Re: bulkhead blues
Post by: John Haygarth on July 15, 2012, 08:59:41 pm
I was just making some comments re-possible problem(others many opinions) as I am sure it is a rust problem. The truck industry for one is having a heck of a time with the road anti-icing compound they have used the last bunch of years.So we feel it as well maybe. Sure glad I cleaned and sealed mine up after I bought it and do not fill my tanks ever. John
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 15, 2012, 09:01:15 pm
Dwayne, have you considered abandoning the broken Rollocks, leaving them in place and sistering in a few new ones?
Title: Re: bulkhead blues
Post by: Don & Tys on July 15, 2012, 09:02:16 pm
Dwayne, The two outermost Roloks (one on street side and one curb side) are smack dab in the middle of the outer most longitudinal (perpendicular) square tubes on either side. Additionally, the next four on the street side are in the area of the doubled up horizontal tubing. So you have a total of six with no access from the basement side of the joint, at least on the rear of our 99' WTFE U270. It is probably similar on other years because I believe they used the same framing scheme on several different floor plans on the unicoaches. Also on our coach, there was one other Rolok that went into a longitudinal frame member and one other that was so close there wasn't even room to get a nut on the broken bolt from the basement side. Don
Is every rolok accessible by drilling the hole through the fiberglass bottom...even those first two or three at the street and curbside? I can't tell from Don's great photos if there is a box beam perpendicular to the bulkhead on the sides and perhaps at very points across that will interfere with accessing the roloks at those locations.
Title: Re: bulkhead blues
Post by: wolfe10 on July 15, 2012, 10:07:01 pm
Dwayne, et al,
To determine how far toward the center the beams go (i.e. where to drill to access the back of the Rolock to remove it and/or to access the area where you will install the large washer and nut if through bolting) take a magnet and "map out" where the steel structure is in the fiberglass floor just toward the center of the coach from the bulkhead area. I use blue painter's tape to "map out" the bulkheads and then just drill toward the center of that. VERY simple.
Brett
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 15, 2012, 10:29:39 pm
Dwayne,
Why not pull a couple of good Rolocks and check for rust on the threads between the two sides of the 1 1/2" rectangular tubing it goes through? If no rust on the middle approx. 1 1/4" inch of threads, the tube probably is not damp inside. The broken Rolock will have sealed both sides of the tube so after cleaning the rusty area and giving it a phosphoric acid conversion treatment, drill a new hole and install a new Rolock. Drill should be perpendicular as you can get it to the face of the angle iron. After drilling the hole, you could inject several ounces of boiled linseed oil. It will climb all the walls inside. Would be careful for the amount of protectant (no thick undercoat) on the outside so you can get a torque wrench on the nut head in the future. Repeat for as many broken bolts as you have.
Pierce
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 15, 2012, 10:38:46 pm
Rather than coating the heads of the bolts which, as Pierce points out will prevent future torque checks, you might put some urethane sealant on the underside of the bolt head before tightening it down. Ditto for the other bolts if you're going to loosen them.
Title: Re: bulkhead blues
Post by: Dwayne on July 15, 2012, 11:11:55 pm
I'm having trouble imagining how, if avoiding the area directly behind the bolt when a perpendicular beam is present, getting to it with the beam in the way. Wouldn't you be beside the beam with the broken bolt inside it and inaccessible? Brett, are you saying you've done the through bolt operation on bolts near the street or curbside? And it does sound like a good idea to put some sealant behind the bolt before tightening down leaving the heads clean. I am too scared to back out any of the unbroken bolts though.
Title: Re: bulkhead blues
Post by: wolfe10 on July 16, 2012, 10:35:02 am
Dwayne,
The Rolocks are long enough that they go through the box beam (toward center of coach) far enough that you can double nut them from a hole you drill in the fiberglass. The hole should start (i.e. for rear beam just FORWARD of the box beam), The dimensions of the box beam are very easy to determine with any magnet.
And, as my original writeup suggested, soak them for a couple of days with a good penetrating oil before attempting to back them out. I use 50/50 acetone and ATF and apply with a long Q tip to both the angle (broken) end and liberally on the inboard end you will double nut.
Brett
Title: Re: bulkhead blues
Post by: wayne m on July 16, 2012, 10:38:44 am
when these bulkheads are in the construction stage, are the roloks individually torqued or are they put in with an air gun in rapid succession? in other words is it possible some bolts are stripped or broken right from the get go?
Title: Re: bulkhead blues
Post by: nitehawk on July 16, 2012, 01:05:36 pm
I recommend that whatever you do--chamfer the hole where it would be under the bolt head. Many SAE standard bolts come with a specified radius under the bolt head. This radius can cause problems such as incorrect torqueing values (altho minor--errors in reading are present) Also, improper seating that can put a "canting" pressure on the bolt head. With additional force being exerted by rust jacking makes failure more likely. Example: A Holo-Krome 3/8-16 grade 8 socket head cap screw has a callout of .023 R max under the head. Also, all bolts up to 5/8 dia shall have a max of 2 imperfect threads under the bolt head. In the machine building industry we found failures if we did not account for the radii and the imperfect threads in assembly.
Title: Re: bulkhead blues
Post by: John Haygarth on July 16, 2012, 01:53:12 pm
that is an important note about chamfering the hole before installing any bolt as it COULD hold the inside face of head away from plate face and allow moisture etc to build up. Another good suggestion was to put some Polyurethane caulk under the head before bolting tight. 2 good points to note. John
Title: Re: bulkhead blues
Post by: wolfe10 on July 16, 2012, 02:07:46 pm
John,
After cleaning off the angle and bolts with a wire brush on a drill, I masked off the bolt heads, then undercoated. No problem with being able to re-check torque and no possibility of moisture migrating in through the over-drilled angle/serrated head on the Rolock.
Brett
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 16, 2012, 04:04:28 pm
We're not alone in Rolok/bulkhead problems. Metal and Metallurgy engineering - Sheared Fastener (http://www.eng-tips.com/viewthread.cfm?qid=325407)
I personally believe the analysis suggested is preferable to guessing though pretty strong suggestions were made to just increase size/strength of fasteners.
Chuck
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 16, 2012, 04:41:20 pm
Chuck,
That's my photo. Who grabbed it, uploaded it to Picasa and linked it to the engineering site?
Pierce
Title: Re: bulkhead blues
Post by: John Haygarth on July 16, 2012, 05:03:10 pm
Finally had a chance to check all mine and not one is loose-phew!! I will re-clean the areas and spray more undercoating crap on them to make sure all voids are sealed. John
Title: Re: bulkhead blues
Post by: Peter & Beth on July 16, 2012, 06:07:16 pm
Water...it's everywhere you don't want it to be.
When I had the bulkhead repair done at Xtreme. there were two drain holes made at the corners of the rear bulkhead floor to enable any water spilled onto the utility bay to run off and not stagnate in unseen areas of that compartment. I think that's a real good addition to the "fix the bulkhead repair" protocol. I know I'm always spilling water onto the bay floor when using the faucet on the street side. And spilling water when I empty the water heater tank on the curb side. It's inevitable.
Any thoughts?
Peter
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 16, 2012, 06:11:29 pm
That's my photo. Who grabbed it, uploaded it to Picasa and linked it to the engineering site?
Pierce
I have no way of knowing, would suggest if it's truly important that you contact the original poster. I see he has the image on a Picasaweb site, other albums include a Bluebird RV, Prevost, with work going on, the original post was July 7.
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 16, 2012, 08:53:03 pm
Chuck,
No big deal. Was just a surprise to see it at other sites. Am sure the poster just wanted to try to find a reason for the failures.
P
Title: Re: bulkhead blues
Post by: Felix and Gail on July 16, 2012, 09:41:54 pm
Peter, can you elaborate on exactly where the drain holes were made?
Title: Re: bulkhead blues
Post by: Peter & Beth on July 16, 2012, 09:51:09 pm
Peter, can you elaborate on exactly where the drain holes were made?
I'll take pictures and post tomorrow. Peter
Title: Re: bulkhead blues
Post by: nitehawk on July 16, 2012, 11:20:44 pm
Re Peter's mention of drain holes: I used to tell my customers that if they couldn't keep the coolant and chips out of their fixtures then give the coolant and chips a way to get out.
If you can't keep water out of the concerned area then find a way to have it exit with all possible speed in order to prevent heavy rusting. corrosion, swelling of the wood.
A grade 8 3/8-16 socket head cap screw/bolt has a minimum tensile strength of 13,900 lbs.
940 inch pounds of torque will cause failure of a 3/8-16 SHCS. The average tension induced in a 3/8-16 SHCS tightened to yield is10,850# So, do not overtighten!
Title: Re: bulkhead blues
Post by: Peter & Beth on July 17, 2012, 11:13:12 am
Peter, can you elaborate on exactly where the drain holes were made?
I went to look and cannot locate these holes. Either they're too small, or I just cannot locate them. I'll have to call James when we get back from the Indiana Bunes. Peter
Title: Re: bulkhead blues
Post by: Peter & Beth on July 17, 2012, 08:40:38 pm
Here's what the bulkhead area looks like after the fix from Xtreme. Peter
Title: Re: bulkhead blues
Post by: John Haygarth on July 17, 2012, 08:43:48 pm
Peter if it where me I would be cleaning and coating that angle and area with a sealer, too many open holes for my liking. Get a few cans of underbody rubber spray and coat it good John H
Title: Re: bulkhead blues
Post by: wolfe10 on July 17, 2012, 08:49:12 pm
Actually, one can of automotive undercoating and a couple of hours and you are good to go.
Brett
Title: Re: bulkhead blues
Post by: Peter & Beth on July 17, 2012, 09:02:55 pm
I definitely agree. It seems the quality is lacking a bit on this job. I'll coat this area well after plugging the openings left by the vacant Roloks. Peter
Title: Re: bulkhead blues
Post by: Ronb on July 17, 2012, 09:39:29 pm
I am presently doing my front bulkhead. Several bolts broken, but not too much rust jacking. The widest crack is about 1/4" at the angle iron. I found easy way to remove the rust that is caked between the 2" angle iron and the bulkhead. I used a air hammer and blunt end chisel, Air Chisel - Harbor Freight Tools (http://www.harborfreight.com/catalogsearch/result?q=air+chisel) on the angle iron. The rust just cascaded down from the crack from the vibrations it makes. Then I used a saw blade to clean anything that was left.
If you have access to air supply this is the way to go to get the maximum amount of rust out without spreading the joint apart. The air hammer is pretty cheap but does a good job, and it is handy for other projects such as removing a muffler or removing a pulley that is frozen on a shaft, just put the chisel on the end of the shaft and pull the trigger. The vibrations that it produces will walk the frozen part right off the shaft, of course a little penetrating oil helps.
Title: Re: bulkhead blues
Post by: Dwayne on July 17, 2012, 10:31:12 pm
What are you doing for a repair as far as bolts go?
Title: Re: bulkhead blues
Post by: Ronb on July 18, 2012, 10:29:43 pm
I am putting in 3/8 x 3" grade 8 bolts with a 1/4" x1-1/2" square backup washers about 18" apart and about a dozen or more 5/16" x3" Roloks. Before installing the bolts I sprayed 763 rust transformer solution by Chesterton up inside the gap. This should retard any rust in the future. Technical Products - Technische Produkte - Productos técnicos - Technické (http://www.chesterton.com/ENU/Products/Pages/Product.aspx?ProductLine=TPD&Category=Corrosion+Control&ModelID=763)
I will then seal the seam with a good RTV sealent and finish it off with some undercoating spray. I think that will last as long as I have the RV, and it will probably outlast me, seeing as how I will be 73 in October :o
Title: Re: bulkhead blues
Post by: Dean & Dee on July 19, 2012, 04:39:06 pm
Next on the Foretravel to-do list is torquing the Rolocks and undercoating the bulkheads. It looks to be in pretty good shape but where the coach lives in the land of salt and snow now I want to be sure it stays that way. My question is that I have a good Snap-on torque wrench but it only reads foot pounds. Is there a conversion from inch to foot pounds that I can use?
Dean
Title: Re: bulkhead blues
Post by: Michelle on July 19, 2012, 04:45:04 pm
Duh, okay Michelle, that will teach me to type before I think. ???
Hmmm, just for giggles I Googled inch to ft. pound calculators to convert the 250 inch pounds and it says the correct conversion is 1" pound force equals 0.0833333333 foot pounds.
Dean
Title: Re: bulkhead blues
Post by: Michelle on July 19, 2012, 05:00:31 pm
Hmmm, just for giggles I Googled inch to ft. pound calculators to convert the 250 inch pounds and it says the correct conversion is 1" pound force equals 0.0833333333 foot pounds.
Yup, 1 divided by 12 = 0.08333333etc....
Title: Re: bulkhead blues
Post by: Dean & Dee on July 19, 2012, 05:02:05 pm
Hmmm, just for giggles I Googled inch to ft. pound calculators to convert the 250 inch pounds and it says the correct conversion is 1" pound force equals 0.0833333333 foot pounds.
Dean
So it looks like 250 inch pds equals 20.83333 ft. pds.
Thanks, Dean
Title: Re: bulkhead blues
Post by: wolfe10 on July 19, 2012, 05:03:43 pm
And, most 1/2" torque wrenches do not accurately go that low (at least my Snap-on wrench does not). So I use a 3/8" drive inch-lb torque wrench.
Brett
Yep, just looked at my Snap-on and you are right Brett. Goes down to 50-lb. Sigh. Guess I am in the market for an inch lb torque wrench. Dean
Title: Re: bulkhead blues
Post by: Felix and Gail on July 19, 2012, 06:02:32 pm
My Craftsman torque wrench goes down to 10 ft. lbs.
Title: Re: bulkhead blues
Post by: Don & Tys on July 19, 2012, 06:20:31 pm
Torque wrenches are most accurate near the middle of their ranges, rather than near either extreme. In fact, the same goes for most any kind of gauge. So if it goes from 10 to 100ft lbs, it won't be very accurate around 20... I actually had a brief stint in the navy where I calibrated torque wrenches. Don't remember much, but that was a long time ago! Don
Torque wrenches are most accurate near the middle of their ranges, rather than near either extreme. In fact, the same goes for most any kind of gauge. So if it goes from 10 to 100ft lbs, it won't be very accurate around 20... I actually had a brief stint in the navy where I calibrated torque wrenches. Don't remember much, but that was a long time ago! Don
After a brief internet search they seem to range in price from $20. (Harbor Frieght) to $300. and I am sure the quality and accuracy have the same range. In the past I have had good luck with tools from NAPA. I have to pick up some undercoating for the bulkhead anyway so I will see what they have.
D&D
Title: Re: bulkhead blues
Post by: Dave M (RIP) on July 19, 2012, 06:40:30 pm
I am with Brett with the Snap-On torque wrenches, Why I have both Ft Lb & In Lb wrenches. Look at it this way, Snap-On is like haveing a Foretravel Craftsman is like haveing a Fleetwood Both will get you there, one give you the warm fuzzies about the quality. ;D FWIW Dave M
Title: Re: bulkhead blues
Post by: Felix and Gail on July 19, 2012, 06:45:52 pm
I have looked in some of the local stores and have not been able to locate a in. lb. wrench locally.
Title: Re: bulkhead blues
Post by: gam on July 19, 2012, 08:35:06 pm
Try Sears. Gam
Title: Re: bulkhead blues
Post by: gam on July 19, 2012, 08:37:04 pm
Or a pawn shop. Gam
Title: Re: bulkhead blues
Post by: Felix and Gail on July 19, 2012, 10:07:08 pm
Thanks Gam. Will try Sears tomorrow. Would doubt correct calibration with a used unit.
Title: Re: bulkhead blues
Post by: Felix and Gail on July 19, 2012, 10:22:03 pm
If I can find an inch lb. wrench, will compare 240 in lb. with 20 ft. lb. on my old wrench to see if the values are close.
Title: Re: bulkhead blues
Post by: wolfe10 on July 19, 2012, 10:23:09 pm
Guys,
Not sure 240 inch-lbs or 260 inch-lbs vs 250 is super critical.
Yes, you do want sufficient torque to verify that it is holding, and not crank on it so hard you strip it out or break the bolt.
Brett
Title: Re: bulkhead blues
Post by: Tim Fiedler on July 19, 2012, 10:39:30 pm
If youy have a small airport nearby, every aviation mechanic has both a ft lb and inch lb torque wrench in his toolbox, go by, give him a cup of coffee and ten bucks and you can probably get by without a ratchet for life.
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 20, 2012, 12:38:19 am
If youy have a small airport nearby, every aviation mechanic has both a ft lb and inch lb torque wrench in his toolbox, go by, give him a cup of coffee and ten bucks and you can probably get by without a ratchet for life.
If he loans his torque wrench make a mental note to self. "Find someone else to be my A&P mechanic."
Title: Re: bulkhead blues
Post by: Caflashbob on July 20, 2012, 12:47:00 am
The harbor freight small torque wrenches are fairly accurate and very inexpensive.
Title: Re: bulkhead blues
Post by: Dean & Dee on July 20, 2012, 08:59:02 am
The harbor freight small torque wrenches are fairly accurate and very inexpensive.
Because I am buying one just to use on the bulkhead and most likely that's the only use it will get I am thinking the Harbor Frieght one looks pretty good. Even if it's off a few pounds I can't believe it would be an issue.
Dean
Title: Re: bulkhead blues
Post by: Tim Fiedler on July 20, 2012, 09:32:01 am
no, I am a better sales guy than that! For $10 he gets under the coach with his wrench!
Actually, the guy that works on my Tri-Pacer is a great guy and happy to crawl under for free. That being said, I have MOT check every year when I am in Nac now.
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 20, 2012, 10:24:10 am
no, I am a better sales guy than that! For $10 he gets under the coach with his wrench!
Actually, the guy that works on my Tri-Pacer is a great guy and happy to crawl under for free. That being said, I have MOT check every year when I am in Nac now.
Just kidding, nothing like having a helpful mechanic that'll work with you to keep those old birds flying. Owned a '46 Ercoupe 415C, replaced a rear spar under the watchful eye of a guy like that.
Chuck
Title: Re: bulkhead blues
Post by: Felix and Gail on July 20, 2012, 06:10:57 pm
After pricing the quality in. lb. wrenches at Sears today, I feel like Dean. The only time I use a torque wrench is when I change the transmission , differential, fluids, etc. and these parameters are all measured in ft. lbs. I will rely on my craftsman (Fleetwood) ft. lb. torque wrench to test the bulkhead bolts. I am not an engineer, mechanic or even a musician (good on you Don). By the way my "Fleetwood" torque was not cheap when I bought it many years ago.
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 20, 2012, 09:00:18 pm
Anti seize or a lub on the bolt threads mean a reduction in torque when tightening. That means approximately 20% less or as an example, if a fastener is torqued to 100 lbs dry, it only gets about 80 lbs. when a lubricant is used.
Tim, I bought a 135 hp Tri-Pacer in 1968. Burned about 7.5 gph at 100 mph. GREAT plane. Flew it for 20 years. Only wish would have been the 150 hp engine.
Pierce
Title: Re: bulkhead blues
Post by: Roland Begin on July 20, 2012, 09:07:05 pm
I have been reading all the posts relative to bulkhead issues. May I have missed something. I notice that we are all sealing the bottom joint between the angle iron and the box beam, but I got to thinking and looking, is anyone sealing the top of the angle iron. Seems like a good place for water to seep in and have no way to escape. Plan on sealing the top of ours before I seal the bottom. Inquiring minds want to know.
Roland
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 20, 2012, 09:30:29 pm
Planning on doing both when I do mine.
Pierce
Title: Re: bulkhead blues
Post by: Neal Pillsbury on July 20, 2012, 10:09:14 pm
I have been reading all the posts relative to bulkhead issues. May I have missed something. I notice that we are all sealing the bottom joint between the angle iron and the box beam, but I got to thinking and looking, is anyone sealing the top of the angle iron. Seems like a good place for water to seep in and have no way to escape. Plan on sealing the top of ours before I seal the bottom. Inquiring minds want to know.
Roland
Roland, You are exactly correct. From my perspective, where the top of the angle iron meets the vertical plane of the bulkhead is one of the less addressed and more critical of the areas to attend to. It tends to look good (no oxidation or deterioration) and therefore is not addressed much. But, because water (and corrosion catalysts such as chloride ions) can enter the joint, it is a big contributor to the rust jacking and to other forms of corrosion that can effect the joint/bolting. The joint being open to water intrusion, is a major reason that (original design) fresh water tank overflows disproportionately aggravate bolting in the vicinity below the overflow. The top, horizontal surface of the angle iron also tends to collect dirt, sand and grit that sponges up moisture and tends to hold it there longer. The vertical bulkhead on my coach is lightly tack welded, at generous intervals, to the angle iron, and that tack welding is all-intact and still looks good (another reason to believe that bulkhead shear forces are non-contributors to fastener failures).
So what is one to do? Redirect the fresh water tank overflow, clean the top horizontal surface of the bulkhead joint angle iron and the vertical bulkhead metal surface well, neutralize any visible oxidation, and then preserve that joint with either applied coatings (e.g.: PAR 3 step, or undercoating) or keep the joint corrosion neutral with a product such as Corrosion-X. Not difficult, but MUST be routinely inspected and attended to. Good observation, Neal
Title: Re: bulkhead blues
Post by: Dave M (RIP) on July 20, 2012, 10:10:58 pm
Agree on the milk stool with 150 hp, a joy to play with. Dave M
Title: Re: bulkhead blues
Post by: wolfe10 on July 20, 2012, 10:20:19 pm
I have been reading all the posts relative to bulkhead issues. May I have missed something. I notice that we are all sealing the bottom joint between the angle iron and the box beam, but I got to thinking and looking, is anyone sealing the top of the angle iron. Seems like a good place for water to seep in and have no way to escape. Plan on sealing the top of ours before I seal the bottom. Inquiring minds want to know.
Roland
Have you found the upper side of the L bracket unsealed??? Mine was factory sealed-- just crawled under to confirm.
Brett
Title: Re: bulkhead blues
Post by: Neal Pillsbury on July 20, 2012, 10:34:22 pm
Have Have you found the upper side of the L bracket unsealed??? Mine was factory sealed-- just crawled under to confirm.
Brett
Brett, How is yours sealed? I don't believe that mine is. I could be wrong, but I've always thought that it was unprotected. Of course it's way too tight to get a feeler gauge or anything else into the joint , but I see no evidence of a gasket or caulking. I just have tack welds every 12 to 18 inches. Neal
Title: Re: bulkhead blues
Post by: Paul Smith on July 20, 2012, 10:35:19 pm
Quote
So what is one to do? Redirect the fresh water tank overflow,
I eliminate the overflow.
I have a clear plastic tube plumbed into the fresh water tank and stay there and visually check the level of water in the tank by looking at the tube and vowing to never let it overflow again.
So far, so good.
best, paul
Title: Re: bulkhead blues
Post by: wolfe10 on July 20, 2012, 10:37:11 pm
Neal,
Put some water on it and see if it disappears.
Title: Re: bulkhead blues
Post by: Felix and Gail on July 20, 2012, 10:42:56 pm
I had also inspected the area above the angle iron. There is a lot of dirt there but it appears to be tack welded to the bulkhead at intervals and not sealed. Even though I have diverted the overflow vent, this area may need further attention. Will have to clean it and have a closer look.
Title: Re: bulkhead blues
Post by: Neal Pillsbury on July 20, 2012, 11:03:03 pm
Title: Re: bulkhead blues
Post by: John Haygarth on July 20, 2012, 11:38:45 pm
I would have thought that anyone cleaning and checking then sealing the bulkhead area would automatically seal the top too. If not done completely around you are asking for more possible trouble later, even if the factory did seal that edge. I even sprayed about 12" past the joint on both surfaces, that is why I suggested in an ealier post you would need a coouple of cans of Spray rubberised underseal. John H
Title: Re: bulkhead blues
Post by: gam on July 21, 2012, 04:34:57 pm
On my u295 most of the bulkhead rust is in the very bottom area of the joint , and then only the sheet metal that rolled under the fiberglass bottom. Most of the sheet metal that rolled under is completely gone. Gam
Title: Re: bulkhead blues
Post by: Roland Begin on July 22, 2012, 12:18:49 pm
Have Have you found the upper side of the L bracket unsealed??? Mine was factory sealed-- just crawled under to confirm.
Brett
Can't speak to the front bulkhead as I had catastrophic failure there, which I am still addressing. However I did check the rear bulkhead and after removing the accumulated dirt and rocks I scraped the "seam" with a small putty knife. There are some spot welds along that seam. However there is no sign of any sealant having been applied to that area. That will not be the case when I finish addressing this bulkhead issue, welds or no welds. Sure wish I had joined the forum before I purchased, would be in "recreation" mode instead of "major puttering" mode.
Roland
Title: Re: bulkhead blues
Post by: Neal Pillsbury on July 22, 2012, 11:25:53 pm
Have Have you found the upper side of the L bracket unsealed??? Mine was factory sealed-- just crawled under to confirm.
Brett
Brett, I have written this three times and keep losing my drafts. It may be something associated with my attached YouTube file which passes on my unexciting confirmation of no seal (angle iron to vertical sheet metal).
I have proven to myself, at least, that both my after and forward bulkhead joints are not sealed at the angle iron (top surface) to vertical sheet metal joint. Thus, I believe that, for '98 at least, all FT's are not sealed at that joint. After I repaired my failed fasteners, I chose to not seal up these areas with undercoating. When I was in college, I worked in a decent auto body shop and I saw a lot of undercoating horror stories. Applied to improperly prepared surfaces, sprayed-on undercoating can easily do more harm than good by not adhering well which leads to the trapping of moisture and chlorides in undesirable places.
That, and because I don't operate the coach in salt environments any longer, led me to keep the repaired joints open for ease of observation. I just treat them with Corrosion-X to render them corrosion neutral. I believe that Corrosion-X will seep all the way from top to bottom, through my angle iron (top surface) to vertical sheet metal joint.
Anyway, my vertical sheet metal is very thin, (maybe 1/16") and infrequently tack welded, so I'm curious as to how yours is sealed (and which model year FT stopped sealing that interface).
Note: removed YouTube link. Not working properly!
FWIW, Neal
Title: Re: bulkhead blues
Post by: Dean & Dee on July 23, 2012, 10:19:17 am
I just treat them with Corrosion-X to render them corrosion neutral. I believe that Corrosion-X will seep all the way from top to bottom, through my angle iron (top surface) to vertical sheet metal joint.
FWIW, Neal
I have been debating Corrosion-X verses undercoating for my bulkheads. Living in a salt area I want the best rust protection possible. My other vehicles I rinse the undercarridge's off several times a winter. Of course the coach will only be exposed on it's way out of Maine. (We don't return untill spring). As Neal said I have also seen that water can get behind improperly applied undercoatings and wreak havoc. So I wonder what protection you would get from sealing the top and bottom of the angles and simply cleaning and applying Corrosion-X on an annual or semi-annual basis verses undercoating?
Dean
Title: Re: bulkhead blues
Post by: John Haygarth on July 23, 2012, 12:07:55 pm
I agree with Neal and Deans point on the "badly applied underseal" possibly causing later problems, but would add that if you do not clean and properly address this issue BEFORE coating then that is asking for more trouble!! I would hope that anyone doing this job would have taken that for granted, sort of not washing your hands before eating after going "you know where" I had great success with spraying a wax-oil mixture into all the panels ( and underbody) of my 735 BMW (drilled holes then plastic plugs) and not seeing any rust in 20yrs. The thing looked like new when I sold it. I have done the same thing with the FT. I would think if you did spray Corrosion X first then leave for a few days to soak in you could then coat. Double protection?? John H
Title: Re: bulkhead blues
Post by: wa_desert_rat on July 23, 2012, 12:43:43 pm
I would think if you did spray Corrosion X first then leave for a few days to soak in you could then coat. Double protection?? John H
Well I thought about that but not sure how corrosion-x and undercoating would adhere to each other. Yes, prep is vital when undercoating anything. There is a guy not far from me that makes a pretty good living undercoating cars and trucks with a sprayed on paraffin wax. May be something to consider.
Dean
Title: Re: bulkhead blues
Post by: Roland Begin on July 23, 2012, 01:05:03 pm
Does anyone know how to remove one end of the steering control arm without damaging the ball joint or the rubber seal. I do not want to replace the ball joint and/or disturb the alignment. I have to drill 16ea 3/8" holes for my bolts and want to use a magnetic base drill and a jig so that all the holes line up and are centered on the box beam. If I can release one end of the steering control arm I can swing it out of the way and will have room for the mag drill. Suggestions anyone?
Roland
Title: Re: bulkhead blues
Post by: wayne m on July 23, 2012, 01:54:24 pm
I guess we will never arrive at an end all be all consensus as to what should be done to avoid or fix bulkhead problems. this week I had the opportunity to have my bolts torqued. since my bulkheads looked to be in good shape, with no separation, I was surprised to find I had one broken bolt on the forward bulkhead outside passenger side and three broken on the aft bulkhead, two outside drivers side and one outside on the passenger side.
most of the broken bolts I have seen on other coaches also seem to come from the outer locations of the bulkhead. I am in no way qualified to give definitive answers or to arrive at definitive conclusions, but most of the broken bolts I have seen, seem to have suffered from the same stresses that caused them to fail. I also believe that this stress is caused by extreme twisting stresses that are put on the coach from time to time. In addition to this, I believe that the horizontal strength of the bulkheads could have been more evenly distributed had there been more fasteners installed nearer the outer reaches of the bulkheads.
at this time I have no plans to remove the broken bolts, I am however going to avoid through bolting in favor of installing two more roloks of the same size, one on each side of the broken bolts. I will keep the area clean, will apply corrosion x and inspect the area regularly.
I am not in any way offering advice here, this is just my opinion formed from everything I have read here and elsewhere. this is just what I see as a satisfactory and easy fix for my coach.
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 24, 2012, 11:14:40 pm
Wayne,
I tend to agree with your reasoning regarding bolt failure but am definitely in the minority. I think your repair method is preferable to bolting as I am told the thin tubing isn't rigid enough to torque a grade 8 thru bolt to spec. Roloks, due to their nature and the material they are seated in can be driven to spec.
I fully intend to increase fastener density in bulkheads using Roloks. Will replace all 17 year old Roloks and will look at upsizing them as the next size up can be driven in existing pilots. As far as corrosion protection, will use LPS3 which is a liquified wax with excellent staying power-years. One thing to realize about using this stuff or CorrosionX on the faces of the bulkhead angle is that it will work against you strength wise as it's a lubricant and will decrease friction between parts-which is some of what you are trying to achieve with fasteners of course. A good alternative might be a conversion coating like Conquest which is quite viscuous and will wick into the joint. It requires at least a light surface coating of rust to work and will tend to lock parts together and form a hard black durable coating. Like your coach mine is rust free.
Title: Re: bulkhead blues
Post by: El_Dorado on July 25, 2012, 03:09:44 pm
If he loans his torque wrench make a mental note to self. "Find someone else to be my A&P mechanic."
As a former A&P..... X2 I used to spend a bunch of $$$ keeping mine calibrated! Re-calibrated them on a time schedule and if they were ever dropped. As a certified repair station, the FAA required this! Better bet would to bring a 12 pack of beer to the Mechanic and ask him to stop bye with the wrenches!
OK. I have just gone through this entire thread, & checked my bolts. When I bought the coach, I did a visual inspection of both bulkheads and the joint along with the rest of the underbelly steel showed some rusting, but there was no joint separation, could not even get a playing card into it. This morning, I took my trusty Snap-on torque wrench and found some broken roloks, 3 at the front bulkhead and 6 at the rear. two spots are spread wide enough to get a playing card in...... just did not see that at the previous inspection.
Choices are 1: Thru-bolt with big washers only broken bolts 2: Replace all rolocks with bolts 3:sister new rolocks next to each broken one 4: remove broken rolocks and replace with the next size larger..... Seems like just replacing the broken ones with bolts would be the easiest at this point.
HELP to many choices
Steve
I am still confused as to which choice I must do...... only want to do it once
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 25, 2012, 05:29:01 pm
Steve,
I also found others that were rusted solid and broke with a bang when I tried to remove them. It was a fresh break, not from rust jacking. I called several large bolt sources to get opinions. I was told that there was no advantage to ordering Rolocs as they were normally ordered by manufacturers as they were easy and quick to install. A fresh hole could be drilled and tapped and a tap bolt (full thread) installed. Most everyone suggested 316 stainless tap bolts as the best solution. They cost a lot more than 18-8 stainless but I found a supplier with 3/8" 316 tap bolts for under $2 each. Fastenal wanted $6.70 each. I ordered 50 and will double the amount that is presently installed. They are a lot stronger than 18-8 and the most corrosion resistant of anything available. Will install 316 flat washers. Since stainless can gall, anti seize will be used with torque reduced 20% Here is a good article on stainless bolts and includes a section on using stainless with mild steel in wet, salty conditions. http://www.ssina.com/download_a_file/fasteners.pdf (http://www.ssina.com/download_a_file/fasteners.pdf)
I don't see any way of removing the bolts that have broken off. Loosening before checking torque or to inspect risks breaking some off requiring sistering right away to maintain structure 100%.
As each one breaks, I can feel the angle iron is under quite a bit of static stress. The feeling and vibration the whole rig makes is an indication that the coach does not have to be underway for a load to be on the bolts.
Grade 8 bolts would have to be installed with a backing plate at the other end. The last 2 feet from the end bolts go through the .125 wall thickness square tube and into another square tube of only .060 wall thickness. Torquing a grade 8 to specs might be risky even with a backing plate on top of this 16 gauge tube. Corrosion resistance with a plated steel bolt is only as good as the thin coating. That can be compromised by threading it into the tubing, friction under the head when tightening or even from the socket that installed them.
After all this I am still convinced the problem is 100% with rust and rust jacking and has nothing to do with chassis flexing IF the original bolts and tubing have not been damaged from a wet environment, either from road spray for a leak from above. It's just tough protecting the total length of all the bolts down in this location.
I just replaced all the torx drive cap screws where the entry steps fold up (the ones visible when the stair is down). The heads were a little rusty so installed stainless allen button head caps in their place. I had to buy a top quality T25 drive (China T25 twisted) to get all the old ones out as they had also rusted severely and took a lot of effort to remove them. My rig is very clean in almost all areas underneath so this has all been a big surprise.
Pierce
Title: Re: bulkhead blues
Post by: El_Dorado on July 25, 2012, 05:57:01 pm
Cool Beans!
OK... now there is one more choice........I do like this idea better than self tapping bolts. How long of a tap would we need? I have never seen any that are very long. And, what company did you find them for that price? OH yeah, how long?
Steve
Title: Re: bulkhead blues
Post by: Don & Tys on July 25, 2012, 06:36:30 pm
Hi Pierce, Did you look into thread forming taps? These use pressure to for threads. I believe it is similar to the thread rolling process that the Roloks use and makes stronger threads than typical taps. I got one at McMaster-Carr, but they aren't long enough to thread both faces of the tube at the same time, which I believe would be essiental for what you propose... Conventinal taps in the required length (for at least the first 1.5" tube) seem to be readily available. It might be worth using Roloks for the purpose of making the theads, would have to expieriment on some scrap of course... Don
I called several large bolt sources to get opinions. I was told that there was no advantage to ordering Rolocs as they were normally ordered by manufacturers as they were easy and quick to install. A fresh hole could be drilled and tapped and a tap bolt (full thread) installed. Most everyone suggested 316 stainless tap bolts as the best solution. They cost a lot more than 18-8 stainless but I found a supplier with 3/8" 316 tap bolts for under $2 each. Fastenal wanted $6.70 each. I ordered 50 and will double the amount that is presently installed. They are a lot stronger than 18-8 and the most corrosion resistant of anything available. Will install 316 flat washers.
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 25, 2012, 07:11:13 pm
The existing bolts are 3 inches. Here is the site: 3/8"-16 - Tanner Bolt & Nut Corp. (http://www.tannerbolt.com/products/FASTENERS/27@@2e%20STAINLESS%20STEEL/02@@2e%20TAP%20BOLTS-304%20316/1405@@2e%20316%20STAINLESS%20NUTS/2017@@2e%2038-16.aspx)
I ordered a box of 3/8-16 X 3" in 316 stainless. I also ordered two boxes of washers. 5/16" washers usually are a good fit for 3/8" bolts but in this case, I ordered both sizes so I would be able to choose and not wait.
Taps: Taps are available in lots and lots of lengths and styles. Here is a page with descriptions for each typehttp://www.newmantools.com/taps/styles.htm The long types are toward the bottom. If you did not want to wait for an order, you could call Grainger. They have a store in lots of towns.
And if this was not enough, Tanner's fastener page has self tapping bolts, in grade 5 with special corrosion protection. This is what should have been used originally. Fasteners - Ultracon Screws, Screws, Nuts, Bolts, Washers, Buy Online, Everyday (http://www.tannerbolt.com/products/FASTENERS.aspx)
They are only 2 1/2 inch but may reach. Will have to use a rod with a small hook on the end to see exactly how far is needed.
Here are the specs on the self tappers:
• Eliminates thread-tapping operations • E-Form® configuration overcomes friction build-up and reduces drive torque • Roll forms own work-hardened thread to resist loosening cause by vibration or thermal changes • Provides enhanced pull-out performance • Well-suited for metal applications such as steel and aluminum • Flex Technology heat treat provides required strength and ductility • Virtually immune to delayed embrittlement failures • Stalgard GB coating provides 1000 hours of salt spray resistance (per ASTM B117) • Accept standard nuts and washers if required
When I started this whole thing, I thought the tubing on the other side of the bulkhead would be have the same wall thickness as the angle iron and make this an easy operation. Another surprise.
Don,
The grade 5 self tapping screws above may roll the threads to be what you are speaking of. And speaking of that, would a 2 1/2" self tapper reach? Looking at the original Roloc, I don't see any kind of corrosion protection that has been applied.
Pierce
Title: Re: bulkhead blues
Post by: Don & Tys on July 25, 2012, 07:23:42 pm
Good info Pierce! If I remember right, I was considering these as well but I was concerned about the length. If you are overcoming any gap at all under tension, I figured they would be a smidge short... that was about the time I discovered that I would need to remove the guts of the wet bay anyway, so I didn't pursue it. 2" of load bearing length minus any gap, 1/4" angle, washer thickness (say an eighth), 1/16" sheet metal, 1.5" squarte tube = 1 &15/16" plus gap, unless I am adding wrong. Add to that the possibility of being a bit off perpendicular... too close to call IMO... If only these came in 3", it would be perfect!
The grade 5 self tapping screws above may roll the threads to be what you are speaking of. And speaking of that, would a 2 1/2" self tapper reach? Looking at the original Roloc, I don't see any kind of corrosion protection that has been applied.
Pierce
Title: Re: bulkhead blues
Post by: Don & Tys on July 25, 2012, 07:34:27 pm
Good info Pierce! If I remember right, I was considering these as well but I was concerned about the length. If you are overcoming any gap at all under tension, I figured they would be a smidge short... that was about the time I discovered that I would need to remove the guts of the wet bay anyway, so I didn't pursue it. 2" of load bearing length minus any gap, 1/4" angle, washer thickness (say an eighth), 1/16" sheet metal, 1.5" squarte tube = 1 &15/16" plus gap, unless I am adding wrong. Add to that the possibility of being a bit off perpendicular... too close to call IMO... If only these came in 3", it would be perfect! OTOH, they might just be the thing to use as a tap without a washer and if there is no gap to speak of...
Title: Re: bulkhead blues
Post by: El_Dorado on July 25, 2012, 07:50:36 pm
Pearce, Thanks for sharing your research.....
Title: Re: bulkhead blues
Post by: Roland Begin on July 25, 2012, 07:52:50 pm
The existing bolts are 3 inches. Here is the site: 3/8"-16 - Tanner Bolt & Nut Corp. (http://www.tannerbolt.com/products/FASTENERS/27@@2e%20STAINLESS%20STEEL/02@@2e%20TAP%20BOLTS-304%20316/1405@@2e%20316%20STAINLESS%20NUTS/2017@@2e%2038-16.aspx)
And if this was not enough, Tanner's fastener page has self tapping bolts, in grade 5 with special corrosion protection. This is what should have been used originally. Fasteners - Ultracon Screws, Screws, Nuts, Bolts, Washers, Buy Online, Everyday (http://www.tannerbolt.com/products/FASTENERS.aspx)
They are only 2 1/2 inch but may reach. Will have to use a rod with a small hook on the end to see exactly how far is needed.
Here are the specs on the self tappers:
• Eliminates thread-tapping operations • E-Form® configuration overcomes friction build-up and reduces drive torque • Roll forms own work-hardened thread to resist loosening cause by vibration or thermal changes • Provides enhanced pull-out performance • Well-suited for metal applications such as steel and aluminum • Flex Technology heat treat provides required strength and ductility • Virtually immune to delayed embrittlement failures • Stalgard GB coating provides 1000 hours of salt spray resistance (per ASTM B117) • Accept standard nuts and washers if required
Sometimes procrastination pays off. I was putting off drilling holes for the 3/8" bolts. I'm liking the idea of these self tappers. The length 2 1/2" is long enough ifor my front bulkhead and adding nuts on the back side may be a bonus. As I have already cut into the filon and cleared the area out on my front bulkhead I wiil add nuts and washers as well. May be the best of all worlds.
Roland
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 25, 2012, 08:12:25 pm
Roland,
If your going to add nuts, check the photo at the Tanner site. Looks like you have to subtract around a quarter inch on the overall length so the nuts will have enough thread to grab onto.
Don,
Glad you came up with the numbers. I had figured the self tappers were long enough but was also a little hesitant. We have a 1500 mile trip to S.Cal in less than a week in the U300 and want to get things secure just in case.
If anyone has a bulkhead separation issue, it would be easy to make a tool that goes over the horizontal angle iron with an adjustable stop down where the bolts are on the vertical face. It would extend down under the coach several inches . The same tool could be placed on the angle iron at the front end of the coach and then a come-a-long could easily pull the two towards each other so bolts could be installed without having to bridge any gap. Will draw up an illustration of such a tool if anyone is interested.
Pierce
Title: Re: bulkhead blues
Post by: Don & Tys on July 25, 2012, 08:32:03 pm
I was actually desperate enough to consider using a couple of garage door tensioners installed on the coach if we decided to try for Texas...LOL. A sturdy comealong should be able close the gap particularly if you add a bit of leverage to the mix as you say (perhaps like a sturdy piece of retangular tubing inserted between the trailing arm shackles). Pierce, if you make it as far south as San Diego maybe we meet up in person... Don
If your going to add nuts, check the photo at the Tanner site. Looks like you have to subtract around a quarter inch on the overall length so the nuts will have enough thread to grab onto.
Don,
Glad you came up with the numbers. I had figured the self tappers were long enough but was also a little hesitant. We have a 1500 mile trip to S.Cal in less than a week in the U300 and want to get things secure just in case.
If anyone has a bulkhead separation issue, it would be easy to make a tool that goes over the horizontal angle iron with an adjustable stop down where the bolts are on the vertical face. It would extend down under the coach several inches . The same tool could be placed on the angle iron at the front end of the coach and then a come-a-long could easily pull the two towards each other so bolts could be installed without having to bridge any gap. Will draw up an illustration of such a tool if anyone is interested.
Pierce
Title: Re: bulkhead blues
Post by: Pierce & Gaylie Stewart on July 25, 2012, 09:21:41 pm
Don,
This one is to Santa Barbara. In October, we are headed to Kent, OH, S. Carolina and across the U.S. via the southerly route. Will hit Puerto Panasco for a little while and would love to stop by unless you are our way earlier. Pulling a horse trailer with household stuff for the kids so will be w/o toad.
Possible Mulege or PV late in the year. Would love Company.
Pierce
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 26, 2012, 07:18:51 am
Thinking back over a suggestion Pierce made regarding sloshing the inside of the square tubing with linseed oil a la Taylorcraft, might it be possible to seal the tube enough to just fill it with oil? That'd take care of the need for anything other than a standard 3" Rolok. Even if it wasn't possible to permanently fill it, a one time soaking with LPS3 would permanently coat both new and old bolts with greasy wax.
A couple of considerations though. The vast majority of original fasteners do not fail. The ones toward the outside of the bulkhead seem to be the culprit for whatever reason. Adding fasteners in this area, whether corrosion resistant or not would most likely solve the problem for many years to come.
Title: Re: bulkhead blues
Post by: Dean & Dee on July 26, 2012, 02:37:38 pm
Got up my courage this morning and crawled under the rear bulkhead to clean, wire brush and undercoat it. I had to remove the sewer hose tube to be able to access the top of the angle. I noticed that there were 4 evenly spaced plastic plugs under the beam and 4 different type of bolts above each. Also noticed a waxy substance squished out around several of the bolt heads.
I am guessing that someone had FOT or another shop drill the access holes and add the 4 evenly spaced bolts. I am hoping the waxy stuff is the result of the beam being sprayed or treated at that time. There was no rust in the bottom seam or on top of the angle and everything looked really good. I vacuumed all the gravel etc. off the top of the angle then wire brushed everything with a drill and rotary brush then scrubbed it all down with paint thinner. Masked off the bolts and just beyond the plastic plugs then blew a can of undercoat on it. It was quite a job but I am confident that it's well protected and was worth doing. I intend to do the same to the front bulkhead. The only thing I would add is make sure you wear throw away clothes. That undercoat get's on everything. Dean
Title: Re: bulkhead blues
Post by: michaelespitz on July 26, 2012, 11:45:27 pm
Dean, My 2003 has the same four plastic covers with nutted bolts front and rear. It looks to me like it was part of the original build because those four bolts are spaced evenly along with the Roloks; in other words they're not sistered beside another bolt. Also, the four nutted bolts are evenly distributed across the beam, same front and rear. As with yours, several of my bolt heads also show what looks like a caulk or sealant under the head. If you remove those plastic covers, you can get a look inside at the nut and the condition of the inside of the tube. They simply snap back in.
Mike 2003 u295, #6063
Title: Re: bulkhead blues
Post by: Dean & Dee on July 27, 2012, 07:59:57 am
Dean, My 2003 has the same four plastic covers with nutted bolts front and rear. It looks to me like it was part of the original build because those four bolts are spaced evenly along with the Roloks; in other words they're not sistered beside another bolt. Also, the four nutted bolts are evenly distributed across the beam, same front and rear. As with yours, several of my bolt heads also show what looks like a caulk or sealant under the head. If you remove those plastic covers, you can get a look inside at the nut and the condition of the inside of the tube. They simply snap back in.
Mike 2003 u295, #6063
Yep, that's why I used the words "quessing" and "hoping" because I wasn't sure and had not seen any mention of the plugs etc. in previous posts. I took a look at the undercoat this morning and I think I will spray another coat on it before I move to the front bulkhead. Had a few thin spots and I want to make sure the top and bottom seams are well covered.
Dean
Title: Re: bulkhead blues
Post by: PatC on July 27, 2012, 01:53:25 pm
As far as corrosion protection, will use LPS3 which is a liquified wax with excellent staying power-years.
The "liquified wax" thing caught my eye. This is similar to what VW and Mercedes uses on their vehicles when new as a undercoating. Works great. And I was thinking, fire apparatus here in the northeast rust out very fast. The trucks get washed after every fire -- The reason they rust is that there are so many places on the undercarrage where water sits after the vehicle is washed. And the manufacturers don't put anything there to prevent it. The LPS3 and some drainage holes sound like the ticket to prevent that.
Title: Re: bulkhead blues
Post by: John Haygarth on July 27, 2012, 02:23:09 pm
I posted about that stuff on the 23rd and used it for many years on the BMW. No rust after 20 yrs. I still have the low pressure spray gun and wands and product for doing coach. The last 5 gall pail I bought was made by Krown undercoating products. I think it was around $200 for the pail, but worht every cent IMHO John
Title: Re: bulkhead blues
Post by: Chuck Pearson on July 27, 2012, 04:52:01 pm
LPS3 is great stuff. As a tech at the marine science institute we used it by the 5 gal pail. Electrical disconnects outside in the salt air breeze and spray would rust away in two years without it and only federally funded vessels could afford stainless steel. The handles would disappear first, making the unit inoperative. Spraying them down with 3, I put some in and fourteen years later were still in fine shape. We coated every outboard powerhead with it till it dripped, avoiding the oxygen sensors and belts, and you could loosen any bolt on the engine years later. All in a saltwater environment. Every year or so things would get another heavy coat, it builds up. It's kind of grody looking stuff but if you need to clean it off spray brake cleaner or similar solvents will remove it. We dispensed it with hand spray bottles.
When I retired I felt a little uneasy without the stuff around so I bought a five gallon pail for myself. Lifetime supply.
Title: Re: bulkhead blues
Post by: El_Dorado on July 27, 2012, 07:17:25 pm
Used that stuff in the Aircraft industry also! You could fog the inside of a wing or amphibious floats and it would be very well protected. It is fantastic and will creep itself into the tiniest spots!!
Title: Re: bulkhead blues
Post by: Roland Begin on August 15, 2012, 09:49:40 pm
I have been working for several weeks to repair the catastrophic front bulkhead failure that occured while we were in Louisianna. My post in the "HAS THIS HAPPENED TO ANYONE" post had photos of my major bulkhead failure. A local welder in Louisanna welded several 3 inch angle brackets to the existing angle iron to support the "floor". This bandaid got us to Maine where I could address the final repair. And that is what I have been doing for several weeks. With the help of a local welder we pulled the front axle as far back as we could using a 1 1/2 ton chain come along. Initially I was going to remove the angle irons that were welded on in Louisianna at Brett's suggestion. Decided against it however as I thought the additional support would not hurt. Just jacked up the floor a bit to reduce the resistance while pulling the front axle back. Then we welded the added angle irons to the bottom of the box beam. Also did a bit of stitch welding. Now the REAL work began as I had to drill 17 holes through the angle iron and box beam. This is where the intuitivness of a local "redneck" (my son) came in real handy. The photos show the brain versus braun approach to drilling holes through 7/16" of steel.
Title: Re: bulkhead blues
Post by: Tim Fiedler on August 15, 2012, 11:13:36 pm
nicely done, and a great sense of humor -
Lots of noise and angst on this forum about the bulkhead issue - looks like you had a pretty bad case, if I can ask, what in total did this "catastrophic" incident set you back financially, and how confident are you that the issue is solved once and for all?
Seems to be a variety of opinion on this topic and you have one of the more significant separations that we have seen to date. If yours was "affordable" and you have confidence in the repair, that would do a lot to put others minds at ease
Thanks!
Title: Re: bulkhead blues
Post by: Roland Begin on August 15, 2012, 11:45:25 pm
Total cost was less than a thousand dollars. The welder in Louisianna charged us $350. The welder in Maine worked on the rig a couple days and charged us $300. I have a couple hundred dollars in materials, nuts, bolts; washers, drill bits, one step rust treatment, cutting oil, undercoating. I have complete confidence that once I have installed the 17 bolts (7 to go) that the bulkhead is going nowhere. I will thoroughly check the rear bulkhead and address any needs there. Once that is complete I feel I will be in Bulkhead heaven. As long as I keep an eye on them I just don't believe that bulkheads will be an issue.
Roland
Title: Re: bulkhead blues
Post by: Dave Head on August 16, 2012, 12:12:02 am
Have you or are you planning to check axle alignments left/right and forward to aft? That would be my main concern.
Title: Re: bulkhead blues
Post by: Roland Begin on August 16, 2012, 09:25:07 am
Had given that some thought, however took the coach to western VT., just a bit under 500 miles round trip, before the job was finished. The coach tracks like an arrow, don't think I'll mess with it just now. Will keep an eye on tread wear for any signs misalignment. Other than that think i"ll leave it as is.
Roland
Title: Re: bulkhead blues
Post by: Dean & Dee on August 16, 2012, 09:51:34 am
Nicely done Roland. Looks like a big job but you probably saved mucho deniro doing it yourself although I didn't see the redneck lube costs included in your calculations. :D
Dean
Title: Re: bulkhead blues
Post by: Kerry on August 21, 2012, 07:25:53 pm
In reading the 11 pages of posts, what would be the problem of reinforcing the angle iron from FOT with angle iron as per Rolands coach. On my front angle iron or behind my front tires in our first compartment is our propane tank and fuel tank is. I have a little rust on the angle iron at the front of the compartment on the floor where the propane tank and compartment door opens. It looks like I get water from driving in rain that splashes into the compartment from the bottom drain at propane tank. I have thought of making a "diffuser" to divert rain water from splashing into compartment. With the weight of the propane tank and fuel tank I have thought of also adding some "reinforcement" to this area. Can anybody see or think what future problems this might be? Thanks
Title: Re: bulkhead blues
Post by: wolfe10 on August 21, 2012, 07:58:04 pm
Kerry,
I added a "defuser" below the safety opening below the propane tank right after we got the coach. Spaced it down with aluminum box tube so any propane would still be able to drain with the "defuser" a sheet of fiberglass several inches wider and longer than the opening. So, water intrusion into that compartment is minimal.
Not sure I understand the "reinforce the angle" statement. The angle has never been the problem-- at least on all the coaches I have inspected. The problem is water intrusion/damage to the box beam, whose walls are 1/2 the thickness of the angle and if water gets in, no way for water to get out.
Title: Re: bulkhead blues
Post by: Kerry on August 21, 2012, 09:28:15 pm
Brett do you have any pictures of the diffuser you built?
https://www.foreforums.com/index.php?action=dlattach;topic=15737.0;attach=10348;image In this picture Roland had angle iron that goes rearward from the angle iron that FOT installed...I wondered if it wouldn't add extra support to the propane compartment if and in the case of a catastrophic failure? Could you see a problem installing maybe 2 supports on the sides say behind the tires? Thanks
Title: Re: bulkhead blues
Post by: wolfe10 on August 21, 2012, 09:37:31 pm
Kerry,
Will try to get a photo of the diffuser next time I am over at the coach.
I see not gain from the "back-facing" angle nor harm. Unless it is bolted into the box beam (I guess from the bottom), it serves no purpose-- unless one assumes its purpose is to support that area in the event that the entire bulkhead fails (as it did in his case).
Said another way, having a beam that is under the fiberglass floor, but connected to nothing is-- well-- not worth much.
Title: Re: bulkhead blues
Post by: travelite on August 21, 2012, 09:50:54 pm
The angle iron Roland added doesn't offer any real resistance to bending. It's section thickness is too thin. Bending stresses will only be resisted by the thin 3/8" cross section of the added angle steel, and the stresses will be concentrated at the apex of the 90 deg angle. If you could wrap another angle around the top of the box section and attach it to the 1/4" angle iron and the box section then you'd have a section modulus that could reasonably resist a bending moment. The roloks work against bending cause you're clamping the 1/4" angle iron to a face of the 1.5"x1.5"x0.125" box section. In this way bending moments are resisted by the bolted joint composed of the full width of the box section and the mating angle iron, clamped under preload. IOW's, the 1/4" angle iron needs to be supported by a full face of the box section, from the top face to the bottom face. It's basically the same reason why welding a bead at just the bottom doesn't work. David
Title: Re: bulkhead blues
Post by: Roland Begin on August 21, 2012, 10:45:58 pm
The angle Iron that was added to my Coach in Louisiana supported the front bulkhead and got us to Maine. Instead of removing this angle iron I had a local welder weld a bead along the bottom of the box beam and the added angle iron. On one piece of added angle iron he also welded a bead across a longitudinal box beam for a total of three beads along that piece. I thought that those additional welds would provide a bit more strength to the area. I have also install 17 3/8 inch bolts to the front bulkhead. Were the welds wasted time and effort?
Roland
Title: Re: bulkhead blues
Post by: Neal Pillsbury on August 21, 2012, 11:21:40 pm
................................On my front angle iron or behind my front tires in our first compartment is our propane tank and fuel tank is. I have a little rust on the angle iron at the front of the compartment on the floor where the propane tank and compartment door opens..............................................
Kerrybob,
The rust that you are seeing in the inner forward corner of the propane compartment is likely from another source, at least it is on my coach. First, the forward bulkhead of the propane compartment is a latticework of 1.5" X 1.5" X 0.125" box channels, covered by inner and out sheets of metal.
In order to promote air flow into the propane compartment, there is an aluminum or plastic covered inlet vent through the outer sheet metal. It looks just like the freshwater tank overflow setup at the rear bulkhead, behind the curbside duals (see overflow photos attached). The propane and battery compartment inlet vents are up behind the front tires, almost behind the airbag. Inside the propane compartment, there is an uncovered round hole (somewhat offset toward the coach centerline from the outer hole) through the inner sheet metal of the bulkhead.
The rust comes from water and mist thrown up by the front tire, which enters the outer sheet metal vent hole and then drains down into the space between the inner and outer sheet metal. The water collected is trapped there causing the rusting of the sheet metal and the box channel latticework.
I have had Extreme, MOT and FOT all look at my rusted areas (both sides - propane and battery compartments) to see if I need to be (more) concerned. Consensus: · Not a structural concern. · Keep dormant with Corrosion X · It wouldn't hurt to open up larger inspection holes in both compartments, for routine inspection purposes. These can be made neat and closed off with removable inspection ports.
If you have the vents, I believe that's probably your source of water that's causing the rust. Neal
Title: Re: bulkhead blues
Post by: Kerry on August 23, 2012, 06:52:09 am
Thank you Neal and Brett,
Neal it looks like that is only on later models, I checked our coach and that would make sense but I don't have the extra hole or vent. I did inspect my coach better and the sheet metal is what seperates my propane area from the tire and bulkhead screw area. I will clean and Ospho or Corrosion X and then paint with an epoxy paint.
Brett have you posted pictures on here before tried a search but couldn't find the diffuser picture.
Thank you all. Kerry
Title: Re: bulkhead blues
Post by: wolfe10 on August 23, 2012, 10:01:50 am
Diffuser under propane locker vent to keep road spray out of the locker yet not impede air flow if there were a propane leak.
Title: Re: bulkhead blues
Post by: Roland Begin on August 31, 2012, 02:39:40 pm
FINALLY......finished repairing my front bulkhead. May not be the most elegant or neatest solution, but there are no places where water can infiltrate between the angle iron and box beam. With the 17 bolts and the angle iron supports I will no longer worry about my bulkhead as we mosey on down the road.
Roland
Title: Re: bulkhead blues
Post by: Don & Tys on August 31, 2012, 04:14:42 pm
^.^d ^.^d ^.^d Way to git-r-dun Roland! Looks a 1000% better. I hope to be posting similar news before too long... to bad life has to get in the way of desired progress at times! Don
FINALLY......finished repairing my front bulkhead. May not be the most elegant or neatest solution, but there are no places where water can infiltrate between the angle iron and box beam. With the 17 bolts and the angle iron supports I will no longer worry about my bulkhead as we mosey on down the road.
Roland
Title: Re: bulkhead blues
Post by: gootie on August 21, 2024, 05:52:08 pm
What year did Foretravel modify construction technics to eliminate the corrosion/bolt problem?
Title: Re: bulkhead blues
Post by: rbark on August 21, 2024, 07:42:33 pm
I'm not sure if they ever did! Best practice is don't let water get into your bays. I'm sure more knowledgeable people will chime in.
Title: Re: bulkhead blues
Post by: Elliott on August 21, 2024, 09:04:34 pm
What year did Foretravel modify construction technics to eliminate the corrosion/bolt problem?
2005 is the last year of it I believe. Possibly 06 if you can find one?
Title: Re: bulkhead blues
Post by: steve on August 22, 2024, 07:57:17 am
Foretravel created a bulkhead inspection guide for 1988-2005 coaches. This goes over the inspection of how the front and rear modules were attached to the sub-floor (where the separation happens). 1988 thru 2005 Unibody Module/Subassembly (bulkhead) Inspection (https://wiki.foreforums.com/doku.php?id=technical:chassis:bulheadinspection) Given this, you know FT was concerned about those model years.
Although that goes back to 1988, earlier coaches have suffered the same/similar problem. Brett has an excellent write-up on this. Foretravel Bulkhead Repair-- A Comprehensive Look (https://wiki.foreforums.com/doku.php?id=technical:chassis:bulkhead)
Starting with the 2006 Phenix, Foretravel used Huck bolts instead of Roloks, I've not heard of any issues on that generation but you should still do an inspection as the where/how a coach is used are outside of FT's control.
Title: Re: bulkhead blues
Post by: wolfe10 on August 22, 2024, 10:56:31 am
Jim,
If they did not use a sealer/caulk when installing the vertical bolts through the fiberglass, I would suggest you do that.
Also, to waterproof the horizontal bolts through the angle, I wire brush the angle, then mask off and spray with automotive undercoating.
You don't want water migrating in the threads when driving through rain.
Title: Re: bulkhead blues
Post by: fourdayoff on August 22, 2024, 11:41:30 am
I had heard that Thomas Welding in Nac is no longer doing repairs on bulkheads. Anyone know if this is true? Jim.
I would ask Keith R
Title: Re: bulkhead blues
Post by: rbark on August 22, 2024, 12:10:53 pm
Wow! No washers on the vertical bolts?
Title: Re: bulkhead blues
Post by: Rudy on August 22, 2024, 04:15:29 pm
Thomas has indeed stopped bulkhead welding. But Atkinson Body repair, which is next to Keith Risch has picked up the welding. And Keith is right there, just steps away.