Working on our '97 u295. Longer story short, after finding some rust damage by the drop door that had been covered up with Bondo I removed much of the bottom fiberglass to see what other problems there might be. Luckily, it doesn't need floor replacement like some have found. While the bottom is open, I want to clean up the rear bulkhead joint and put in 3/8" bolts. I think I have the answer from some of the older threads (thanks especially to Don and Stump) but just want to confirm that the joint is under tension and all of the bolts can be removed? I would block up the floor just in case while under there. Safety stands in the suspension of course. Thanks.
Are you trying to clean between the angle iron and the square tube? If yes I personally would install long through bolts first, one on each side and one in the middle before removing all the Roloks. then you have something to keep alignment while cleaning up. If you are just adding the bolts do one at a time.
As long as nothing is actively working to separate the joint, nothing is seriously bent and you are on level ground, the joint is not being pushed apart by gravity. I have previously posted my technique for controlling the separation of the joint for purposes inspection or cleaning out rust using a couple of bottle jacks placed along side either the forward or rear air spring. Placing the bottle jack alongside the front air spring will separate the joint while placing it alongside the rear air spring will push it closed.
Don
Edit: adding link to a post where I attempt to describe my method of controlling the bulkhead joint separation for purpose of inspection and rust removal. Bulkhead Separation - Planning for the Worst (http://www.foreforums.com/index.php?topic=23330.msg181095#msg181095)
Right after we bought our coach and got it home and even though the bulkhead was very clean, I tested the bolts. Several broke off so I loosened about a three foot section and forced the angle iron away from the square tubing with a tapered flat chisel and a single jack. I then used a Sawzall with a carbide blade to loosen the rust hiding behind the angle iron. The photos show how clean the bulkhead was and the amount of rust behind it.
The first time any Foretravel with this type of construction goes through a puddle or is driven in the rain, water collects behind the angle iron and the rust process begins. It's not if there is rust there, it's how much rust is there. You can see the huge chunks I removed. This was 13 years ago.
No good way of sealing the area as water/road chemicals can get in at the vertical members and migrate down to behind the angle iron. If the angle iron is sealed, the moisture will not be able to get out and continue to do it's damage. The arrows point to the areas where water may enter.
Pierce
Ok, thanks guys. Just wanting to make sure I wasn't missing something.
Cm, yes I am wanting to open up the whole thing. I like your idea of 3 long bolts to keep everything aligned just in case. Don, thanks for the link. I've read through many of your helpful posts. P, I've seen your pics. Your pic with the red arrows definitely shows part of the problem with these.
Nice to be able to do an MRI or CAT scan on the belly of the beast but as you say, opening up the whole thing will give you a picture of the condition, front to back. The front bulkhead may have the same problem as the rear so it's not to be forgotten.
Forcing the bulkhead apart, cleaning as much rust as possible and then injecting a primer of some kind will help.
Long though bolts, either stainless or grade 8 will do the trick. As I remember, 4 or 4 1/2 inches is the length needed. Torquing to specs will not deform the square tubing. Nylocs will also do the trick. The area is open at both ends in the propane/fuel tank compartment so you can measure the exact length needed. 316 stainless is better than 308. Order off ebay and they are cheap for a box. Same with nuts and washers. I went from 5/16" to 3/8" bolts in the areas where I changed them.
Pierce