Went to open the basement door today and only one side wanted to come up, the other side needed to be coaxed. Apparently the bolt/pin that holds the brass spacer at one of the pivot/hinge joints broke off. Looks like a cap screw (allen head) about 2" overall length. 5/16 " in diameter at the body that carries the brass bushing. The very end looks to be a smaller diameter 3/16" with male threads. Anyone know where to get these?
Thanks
Eric
I take that back. Upon further inspection it appears to be a 5/16" cap screw with a long body (about an 1-1/4") the threads are worn off at the end and measure 3/16" (what's left). So I'm guessing it's 5/16" all the way, is that correct?
I get them from Fastenal. On your coach you should have 3 different lengths of these bolts. I have the Fastenal part numbers but it will be tomorrow before I can get to them so I can post them for you.
I thought that I had posted this info before in the part number section but can't find it tonight. (Mike is watching the "Chili Bowl" so he is limited help tonight)
Pamela & Mike
Thanks Pamela, I'll take the pieces I have left and get them matched up.
I got 2 bolts and a bushing from FT, 30 bucks. A trip to Fastenal is well worth it.
Support your local hard core hardware store while you can. Fastenal is no bargain either and have limited hours. My nearest Ace has 3 aisles of about any fastner you need or could imagine for about 80% of the cost of the big box stores, which have a very limited supply of Chinese blister packed crap. This includes high grade cap screws and assorted bushings. The bad news is it has been bought out by Westlake Ace hardware, which is a home improvement type joint. About 40 minutes drive away I can go to a joint called the Yard Store and buy aircraft grade surplus fasteners for a buck per pound. Support your local hard core hardware store. End of rant
I carry several sets of bay door hinge parts that I buy from FT Parts whenever the supply gets down to one. find/keep the parts that fall off when the the bolt breaks. I don't know how you could find generic bolts that would fit the threads in the lever arm and still allow the brass roller to slide on.
Opp,
You might be able to find something that you could "Jury Rig" at a local hardware store, but I have never been able to find a Stainless steel shoulder bolt at a hard ware store, box store, home improvement store that is correct. On a bolt like this you could take a piece of 308 bar stock to a local machine shop and have them run you a couple to support the local economy. I find it much more convenient and faster to go to a bolt supply company. If there is a local supply house that is what I use. With someone on the road a national store (no name mentioned to keep from offending any one) will be easier to locate what you need for a proper repair.
@ Mobius,
Here is a pic. of the 3 sizes that was OEM on various pivot points on your doors. I don't know what could have been substituted by previous owner. Here is the part # from the Blue building nationally known fastener company. With this info you can cross to the net or any fastener store of your choosing.
long one 5/16" X 1-1/4 0176915
medium 5/16" X 3/4 74107
short 5/16" X 3/8" 0176913
Pamela & Mike
Ah, SS shoulder bolt, that does complicate things substantially. Spares when you can find them might be prudent, because FOT's supply may run dry at some point.
My local Ace Hardware has a very good bolt selection and they keep them in stock.
Eric,
Those are called shoulder bolts. You should be able to find what you want at Home Depot or Ace Hardware.
John M.
We jury rigged one of our doors with a regular bolt and a brass bushing that we happened to have (HOW did THAT happen???) in our conglomeration of meaningless stuff that you just might need one day. Turns out we actually needed it! We later bought a few shoulder bolts when we could and kept them on hand.
Thanks everyone,
That's the information I was hoping to get, I'll start with our local Ace then move on from there if they don't have them.
I know that the purists among us won't like this, so if you suspect this may describe you, read no further... >:D
Now for the second time, one of the hinge bolts has broken and once again I am unable to extract the shoulder bolt through the brass bushing by pulling on the head. Last time I happened to be in Nacogdoches and picked up the full assembly at Foretravel. (NOTE: if you ever need these parts from them, provide not only a photograph, but also the measurements, as they are very unlikely to get it right based on year, model or build number.) Bernd's crew replaced it then. This time I found myself with a day off (and without this post), so I decided to tackle it myself, realizing that this may be recurring.
The first challenge was to remove the bolt. Again, it would not be extracted by civilized means, so I tried to force it by setting a chisel between the washer and the support arm, which would have the effect of sliding the bolt and bushing in opposite directions, in effect pulling the bolt out of the bushing - same as pulling on the bolt head, but with more force than I could manage otherwise. All I managed to do was deform the brass washer - but it was enough to get a hack saw in place to cut the bolt.
Once I got the pieces out I was still unable to remove the bolt from the bushing by pushing it toward the end where the head used to be. But lo and behold - it could be pushed out in the other direction, toward the nut end. It had not seized - it was always possible to turn the bolt and the bushing against one another - I just couldn't pull the bolt out. Once I got the bolt removed from the bushing (now with no threads or head) it was clear that a ridge must have formed; It had to be, otherwise how would the bolt have been inserted in the bushing to begin with? Here is a photo of the bolt. Notice the slight cusp on the shoulder toward the threads - that cusp is what prevented the bolt from being pulled out of the bushing:
Shoulder bolt reconstructed (https://photos.app.goo.gl/aADpejv64Wd29mVu2)
There is no Home Depot or Lowes or anything like it within a reasonable drive, so I settled for a 2" x 5/16-18 bolt and nylon locking nut, plain and simple (re-using the brass bushing and both brass washers). The one modification I had to make was to enlarge the hole in the fixed support where the pivoting arms attach, from 1/4" to 5/16" body size.
For those who have never dealt with this - if you removed the one gas spring as I had when the pivot broke, it will need to be compressed in order to reinstall it. For that I used a ratcheting tie-down strap. Just arrange it so none of the strap hardware will be in the way of getting the ends reattached, and you'll get it on.
The downside now is that threads run most of the length of the bolt, through most of the bushing and through one set of pivoting arms and the support where they attach. The upside is that there is now 1/16" more on the diameter at the stress point (where the arms pivot). I guess I'll see how well this holds up.
I have a door on the drivers side by the muffler where the safe is,no compartment just a door,I took the good bolt from it and
used it on a door that gets more use and just used a bolt on the door we never use.
John - a couple of things I'm confused about:
- Is your safe located on the exterior of the coach? Mine is in one of the bedside units in the bedroom.
- On my coach the "door to nowhere" - on the opposite side from the batteries (batteries are on passenger side, "door to nowhere" a/k/a access door is on driver side). That door has a simple piano hinge rather than a pantographic hinge, leaving me to wonder how one could do a pantographic hinge hardware swap between that and one of the large storage bay doors (the ones that don't have piano hinges due to awning supports, or maybe slideouts above them).
We may be talking about 2 different parts,I meant the part the lock latches onto.
I don't have panto-graphs on my coach but it sounds like the bolts are not strong enough.
In the photos they appear to be stainless steel which doesn't seem necessary in this application. Plain steel versions of the same screws should hold up better.
McMaster-Carr has a large variety: McMaster-Carr (http://www.mcmaster.com/#shoulder-screws/=1b5rmnb)
I suspect the main problem with these bolts is user failure to regularly lubricate the door hinge systems. I know I'm guilty of this. Now when I hear the slightest squeak when operating a door I lube them all again.
Rich, about 2 months ago I too had one of those bolts break but luckily I was able to force it apart and my Brother sent me 6 new shoulder bolts of right size so all back new again. Now the squeak mentioned may also be the shaft of Air springs going dry. I had a consistant one and even after lubing those bolts etc it kept going. I then realized it was coming from springs so put some Syn grease on shafts and instant fix. I then did all of bay doors and they are definitely a lot smoother and no noise any more.
You and others may wan to try those places and see if it works.
JohnH
John,
Somehwere, somehow a "squeak" and "lack of lubrication" crept into the conversation. Please let me clarify:
1) There was no squeak or creak or squawk that would have indicated 2 un-lubricated surfaces moving against each other.
2) There is no residual lubrication evident anywhere in any of the pantographic hinge arm pivot points. Nor do I see any place that suggests a need to lubricate. They don't get hot, they weren't the least bit bound, and the door always opened and closed without resistance.
I think John Fitz nailed it - the bolts are not robust enough. And stainless tends to be a bit brittle (not the preferred material where strength is needed). if you take a look at the photo (in my original post) you will see just how narrow the shaft is at its narrowest; they started with a reasonable 5/16" bolt body, then necked it down to less than 1/4" exactly where it needs the most strength, at the hinge arms. I say less than 1/4" because the threads are 1/4-20 - and the area in question is a detente rather than a shoulder. I would add it to my list of "what the h____ were they thinking?" Those long bay doors are VERY heavy - which you find out very quickly when the bolt breaks.
Another possible contributing factor would be that the gas springs were pretty worn out when I bought the coach 2 years ago. They have since been replaced. I have a sense that if the springs aren't doing their part, the weight of the door is focused more and distributed less? I dunno. I cannot see how lubrication would be a factor. Lubrication would save it from breaking if heat or abrasion were a factor (by preventing the heat / abrasion). In this case *neither* is a factor. It just sheared off at its weakest point - which was too weak to support the weight - plain and simple. Clearly it was not lubricated at the factory, unless all traces of lubrication have somehow disappeared from all hinge arms.
Rich, you lost my point in that I was talking about MY coach squeak after fixing MY door bolt that broke just like youre. I mentioned the air pistons because MINE did stop squeaking once lubed and thought it may be a similar problem on others in this group. I did all of mine and doors swing down easier and no more squeaking-period.
MY mention of squeaks etc was just to have an addional suggestion while on the bolt one.
JohnH
John - Sorry - I didn't get that!
What did you use for lube? I suppose it wouldn't hurt for me to spray something around the bushing/bolt assemblies. I'm thinking maybe PTFE or silicone spray?
Rich,
Even with the lock nuts you need to take an allen wrench and boxed/open wrench and check that the pivot pins are tight. I do this when I spray them with lube. If they are loose (even a little) you can end up with a belled end like you have encountered.
I use dry silicone my self on all pivots, latches, handle workings and shock tubes.
Pamela & Mike
I use plumbers synthetic grease on a lot of parts.
JohnH
OH, OH! Another Rube Goldberg suggestion.
Get a 1/4-20 socket head cap screw the same length under the head as the shoulder/stripper bolt. From someplace like Fastenal. The bolts are about 78 Rc.
Get a drill bushing same outside diameter as the bearing diameter of the shoulder/stripper bolt and the inside dia that will fit over the 1/4-20 bolt. Bushing length same as the round part of the shoulder/stripper bolt under the bolt head and to where the thread diameter starts. Economy headless drill bushing Company comes to mind as a source. Usually available from a bearing supply company.
Assemble bushing onto the bolt and now there isn't a "weak" spot where the threads end at the relief on the shoulder bolt
If the bolts are tight there is no shear taking place at the smaller diameter. The shoulder part of the bolt would have a clamp load of over 2000 lbs. with a grade 5 bolt.
https://www.fastenal.com/content/feds/pdf/Torque-Tension%20Chart%20for%20A307%20Gr5%20Gr8%20Gr9.pdf
My guess is that if it had been built that way to begin with, this whole thread would never exist.
Having no mechanical engineering background to speak of I'll try to parse what you're saying:
If the bolts are tight, there's no slippage between the 2 pivoting arms at the pivot point, and therefore no shear force.
I guess my reply to that would be that the holes in the arms admit a 5/16" bolt with no enlargement required. If that's the case, then since the section of the bolt that occupies that space where the arms pivot is necked down - below 1/4" by the depth of the thread (making it what, 3/16"?) then the potential for slippage in that space is always present - and any slippage between the arms at the pivot point would exert a shear force on the bolt at that point. How's that? So does it really make sense to have the bolt undersized at that point where the arms pivot, or would it have been better to have a sleeve there and let the bolt turn free inside it? I think it's just a poor design. But the point about keeping the bolt tight at all times is well taken. I'll just add it to my ever growing list of things to do periodically.
Where the shoulder of the bolt contacts metal the force of a 5/16-18 nut being tightened is over 2000 lbs. clamping against the metal. There is no movement at that contact point therefore no shear. If the nut gets loose the force is all shear since no clamping force is in effect. All of the movement is along the shoulder part of the bolt.
Maybe we're talking about different locations. In my case, there is movement - pivoting movement between the 2 arms being held together at that point. And where that pivot movement takes place there is a gap of 1/8" on the diameter there between the holes in the arms and the necked-down section of bolt (a 3/16" section of bolt inside holes in 2 arms that are at least 5/16"). There is nothing but clamping force to keep the arms from slipping in the direction of shear. Regardless how tight the nylon threaded nut is, some slippage in the direction of shear due to the pivoting motion is inevitable - there is nothing to prevent that (whereas a lubricated sleeve - or bearings - would prevent it). We must be talking about 2 different locations. I just had mine apart - and I'm referring to the location where my bolt broke. Given the additional weight and leverage of the wide bay doors found on the 40' coaches, a better mechanical solution at the pivot points would prevent the bolt from breaking.
I think my words are failing here, and we all have better things to do, so this will be my last comment.
Here are the pictures of my bay door hinges.
Chuck,
As you've already seen, here are mine (https://photos.app.goo.gl/F3TV2V4vv30dIjUH3) ... I'm glad you pursued this, as even though we both have '99 40' U320s, the pantographic door hinge assemblies are different - yours have nylon washers, and mine do not. Whether they did have the washers when the coach was built is anyone's guess. I'll see if I can get hold of some and retrofit - making sure the bolt shoulders are the correct length to accommodate.
Thanks very much!
Rich