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Topic: Working Safely around your Foretravel (Read 41176 times) previous topic - next topic

Re: Working Safely around your Foretravel

Reply #60 –
Quote from: Neal Pillsbury –
Jon,
I'm curious as to the source of your information regarding the design purpose of the bosses. 
I'm like Don in that a Foretravel sales and service center advised me on the length (11.5") and strength (2"X4"X1/4" web) of the (4) support blocks that I use.  I am using just about what that service facility was routinely using  (they were using (4), 11" long 2"X2"X1/4"web supports, so I have some overkill when compared to theirs). 
It has always been my understanding that the bosses have the following (2) design purposes:
    • Design would rather that the frame members have "point contact" versus "length contact" in extreme suspension travel situations.  That minimizes the chance of exceeding the design stress at the hinge point (e.g. - due to dirt build up on the frame rail).
       
    • Design also wants to fine tune the end point of "aired-down" suspension travel.  Without the bosses, the tire will deform the floor beyond acceptable margins.  In fact, service centers have "shimmed" coaches by building the bosses slightly higher to counteract too much travel when completely "aired down".  Most Unicoaches have tire contact at all four corners when the suspension is fully aired down.  But it is my understanding that the bosses prevent permanently deforming the floor, particularly if aired down when significantly off level and the humidity is high or the floor otherwise contains a high moisture content.
Is it possible that someone is just confusing the bosses as a handy reference point over which (hollow) 7.5" safety blocks can be reliably placed to safely support the coach?
FWIW,
Neal
Neal,
          That's what they looked like to me and I thought they were hard rubber bumpers but I got in there and took a good look at them and they are welded in pieces. Also if you look at the chassis design, it looks like a support block placed at the "shim" points would support the main beam tube as opposed to a beam that is welded above it. The "shim" point location looks like the best place for any blocking/support.

Re: Working Safely around your Foretravel

Reply #61 –
Quote from: Neal Pillsbury –
Quote from: Jon Twork –
........................These bosses were put there to indicate where to put veritically placed round or square tubing approximately 7.5" high for the purpose of keeping the chassis elevated during servicing.  Those who use these bosses always either use four  for front work or four for rear work or eight when working under the whole coach.................................. 
That is my understanding of the situation and I thought I should pass it along.
Regards,

Quote from: Don Hay –
.......................Just as interesting is the fact that my instructions for where to support the frame and how many support members to use were given to me by the (then) service manager at Foretravel.  He had one of the FT guys cut me 4, 2"X2"X11" square tubes, then showed me where to position them, never once mentioning the bosses that were about 6-10" away.  In fact, those 11" tubes wouldn't fit between the frame members at the bosses.  One would, as Jon mentioned, have to go with shorter (7.5") supports. 

Apparently there was an information "gap" (breakdown) between the factory and at least some people in Service.  Whether there still is a gap or that was just an isolated instance remains to be seen.
Jon,
I'm curious as to the source of your information regarding the design purpose of the bosses. 
I'm like Don in that a Foretravel sales and service center advised me on the length (11.5") and strength (2"X4"X1/4" web) of the (4) support blocks that I use.  I am using just about what that service facility was routinely using  (they were using (4), 11" long 2"X2"X1/4"web supports, so I have some overkill when compared to theirs). 
It has always been my understanding that the bosses have the following (2) design purposes:
    • Design would rather that the frame members have "point contact" versus "length contact" in extreme suspension travel situations.  That minimizes the chance of exceeding the design stress at the hinge point (e.g. - due to dirt build up on the frame rail).
       
    • Design also wants to fine tune the end point of "aired-down" suspension travel.  Without the bosses, the tire will deform the floor beyond acceptable margins.  In fact, service centers have "shimmed" coaches by building the bosses slightly higher to counteract too much travel when completely "aired down".  Most Unicoaches have tire contact at all four corners when the suspension is fully aired down.  But it is my understanding that the bosses prevent permanently deforming the floor, particularly if aired down when significantly off level and the humidity is high or the floor otherwise contains a high moisture content.
Is it possible that someone is just confusing the bosses as a handy reference point over which (hollow) 7.5" safety blocks can be reliably placed to safely support the coach?
FWIW,
Neal
Just to be sure of our info here, I went to the expert and asked.

James,
On the newsgroup it is being said that there is a "Support Locating Boss" specifically there for the 2x2x11" steel frame supports that you put for safety.
I always thought that was a bumper stop.
That does not look right to me.
Can you clarify where you put the supports when working under the coach?

His answer.
Where you are putting the 2x2 block or steel bar is correct.
You are right it is the frame stop or bumper stop.

Re: Working Safely around your Foretravel

Reply #62 –
It would appear from Barry's post of 03/21/2011 that James at the factory was willing to weigh in on this matter.  It is gratifying to see that they are willing to provide such information.  This is a very important area. Thank you, Barry and thank you, James.

Re: Working Safely around your Foretravel

Reply #63 –
Quote from: Barry Beam –

Just to be sure of our info here, I went to the expert and asked.

James,
On the newsgroup it is being said that there is a "Support Locating Boss" specifically there for the 2x2x11" steel frame supports that you put for safety.
I always thought that was a bumper stop.
That does not look right to me.
Can you clarify where you put the supports when working under the coach?

His answer.
Where you are putting the 2x2 block or steel bar is correct.
You are right it is the frame stop or bumper stop. 

So if I understand correctly, 4 each of the safety blocks (2"x2"x1/4"x 11" h as a minimum) are required and they are to be placed at each corner of the coach close to the airbag and between the house structural member to which the top airbag flange is mounted and the chassis structural member to which the bottom airbag flange is mounted.

Am I understanding it correctly?

I currently have 4 each of 2"x5"x1/4"x11" h steel tubing pieces cut and ready for use.

Re: Working Safely around your Foretravel

Reply #64 –
Too eliminate any possible confusion, could someone post a picture showing the correct location for the supports?

Re: Working Safely around your Foretravel

Reply #66 –
Quote from: ncaabbfan –
Quote from: Barry Beam –

Just to be sure of our info here, I went to the expert and asked.

James,
On the newsgroup it is being said that there is a "Support Locating Boss" specifically there for the 2x2x11" steel frame supports that you put for safety.
I always thought that was a bumper stop.
That does not look right to me.
Can you clarify where you put the supports when working under the coach?

His answer.
Where you are putting the 2x2 block or steel bar is correct.
You are right it is the frame stop or bumper stop. 

So if I understand correctly, 4 each of the safety blocks (2"x2"x1/4"x 11" h as a minimum) are required and they are to be placed at each corner of the coach close to the airbag and between the house structural member to which the top airbag flange is mounted and the chassis structural member to which the bottom airbag flange is mounted.

Am I understanding it correctly?

I currently have 4 each of 2"x5"x1/4"x11" h steel tubing pieces cut and ready for use.

You have it correctly.
Total of 4. 1 for each corner.

Re: Working Safely around your Foretravel

Reply #68 –
Thank you, Barry. I will follow what I saw in your photo.

George Stoltz

Re: Working Safely around your Foretravel

Reply #69 –
In addition to the safety blocks to guard against sudden deflation of the Air Bags, has anyone here made their own ramps to get the coach higher in the rear for the bulkhead repair? Also, my yard slopes a bit towards the street, and although the Air Bags manage to make it level, I don't like the idea of having the rears maxed out for too long a time, so three layers of 2X10's can raise the rear end by 4.5" to make it a bit easier for the leveler to keep it that way. I am posting two pictures of the ramps I am making. There are 4, one for each of the dualies. I plan to make some spacers out of some 3/8" all thread to keep them in line with each other and to keep them spaced to be centered under each of the rear tires. Additionally, I am going to use wheel chocks on two of the ramps to keep it from going off the deep end. I looked on the web for some commercial solution, but the only heavy duty rams rated for the weight that I saw were extremely expensive. Since the ground is fairly level side to side where the coach sits, I think this should be very stable and will give extra working room. Any comments? Am I crazy or what? (don't answer that!)
Don
edit: Going crazy(er) trying to get these pics to post right side up. They look fine on my computer... what a pain!

Re: Working Safely around your Foretravel

Reply #70 –
Good job. Should give you that extra little clearance you need.

Re: Working Safely around your Foretravel

Reply #71 –
Thanks! I plan to get the coach up on them tomorrow. I will post some pics if I do...
Don

Re: Working Safely around your Foretravel

Reply #72 –
Great looking ramps. I will be making a pair for the front before I attempt my bulkhead repair. Will use yours for a pattern.  Especially like the chock, don't think I would have thought of that.^.^d

Re: Working Safely around your Foretravel

Reply #73 –
Thanks! They have been there for months now... I guess I forgot to post a picture with the coach up on the ramps, so here it is. I can't imagine doing the work I am doing with 4.5" less ground clearance! Remember, there are also eight 1/4" thick walled 2" square tubing posts, 11" long next to each airbag to block the body up off of the suspension. Had I to do it over again, I would have made them 12" high because the air bags are able to provide that much clearance. If you only have two of these post per axle, placing them next to the bulkheads will try to pull the bulkhead away from the basement, so unless you need the clearance to get rust out, my opinion is that it is far better to have one for every air bag. If you choose to open up the gap in the bulkhead this way, I would still use 4 stand off posts but just make the ones closest to the bulkhead joint a wee bit shorter because I shudder to think what would happen if it pulled apart and kept on going. When I did this, I had about 8 long 3/8" bolts through the joint with nuts on the basement side to keep it from going too far. I could do that because I had the bottom skin off and full access to the joint. Your milage may vary! If you want to talk to me about it, feel free to PM me and will give you my phone number. My method was unconventional (and a hell of a lot more work!) because I think the severity of our bulkhead issue necessitated a different approach than the others you may have read about, but that is just my take on it.
Don
Quote from: Roland Begin –
Great looking ramps. I will be making a pair for the front before I attempt my bulkhead repair. Will use yours for a pattern.  Especially like the chock, don't think I would have thought of that.^.^d

Re: Working Safely around your Foretravel

Reply #74 –
I don't know the "anatomy" of a FT suspension system yet, thus my question. I haven't seen any mention of jackstands in this thread, so apparently their use would not be a safe method of preventing the coach from dropping. But why not?

Re: Working Safely around your Foretravel

Reply #75 –
Morning BamaFan,

Rather than jack stands, one inserts 11 to 12 in long square tubes or iron pipe behind each air bag.  The ends need to be cut square so they will stand on the lower beam on which the air bag is mounted.

Lower the bags trapping the support between the top and bottom beams and it will not come down on you unexpectedly.

Re: Working Safely around your Foretravel

Reply #76 –
Quote from: BamaFan –
I don't know the "anatomy" of a FT suspension system yet, thus my question. I haven't seen any mention of jackstands in this thread, so apparently their use would not be a safe method of preventing the coach from dropping. But why not?

Not sure it wouldn't be safe, but putting the "blocks" where the air bags are (front and rear of each wheel position) GUARANTEES that the coach will not come down.  Smaller, less expensive and perhaps 2 seconds each to install/remove.

Brett

Re: Working Safely around your Foretravel

Reply #77 –
Bamafan, Here is photo of what some us have made to act as safety supports.  They are set in between the upper and lower frame members and will support coach is air is lost.
Gary B

Re: Working Safely around your Foretravel

Reply #78 –
When using safety supports, find something that will remind you they are in place, like a ribbon from support to outside of coach.

Several have driven off with supports in place, which can cause lots of damage to coach.

Re: Working Safely around your Foretravel

Reply #79 –
I went to Harbor Freight tools and bought 4 standard receiver hitch tubes to use for safety supports .  They are 2" square and 12" long.  One  end has a welded base that works well to keep it upright when placing into position next to the airbags. They are electroplated and powder coated for rust protection.  Maximum space between the frame supports on my coach is just over 12 inches after starting/airing up, and using the raise button and arrows for manual leveling to its maximum height.  I then lower the airbags till the tubes are snug in between the frame members (can't pull them loose). Not cheap at $17.99 each but a very inexpensive form of insurance when working underneath.  I agree with all the other posts on this subject.  Stay Safe!

Jerry