Frame repair with shell on?

[80BELLA]

I finally got all the interior skins off and the rotted back section of floor out. The back plate is pretty rusted, but the rear end is in better shape than I had feared. But when looking at the grey tank, I noticed the cracks in the cross member. Wow, were these big chunks of metal cut out at the factory? And now the big question, can these cracks be repaired without taking the shell off? I know that many will say it is easier in the end, but Imma scared of a full monty.

[uncle_bob]

Hi

To do a proper job on the frame, you will need to clear everything away from any and all areas that need welding. Step back and take a look at what all needs to be removed. Flooring is a big part of it. Axles also need to be out of the way. All the little stuff like wires and gas lines also are on the list. Fully stripping the frame with the shell on (and then fixing everything) may well be harder than pulling the shell ....

Bob

[blickcd]

Full Monty? I say no. This calls for what I refer to as the Rear Admiral, and you've done all the demo work already.

I would stop drill the cracks. Look that up if you don't know the term.

I would then wire brush the frame in that area to get it as clean as possible, both front and back sides, primer and paint with POR or Rustoleum.

It looks like you have good enough access to then weld it. I would temporarily clamp a steel plate behind the cracked areas, grind your new paint off the cracks, and weld them, then remove the backing plate and grind the welds flush. Prime and paint the ground down areas.

I would then get a piece of 1/16" thick angle iron, maybe 1"x1" and a foot long, my estimate by looking at the picture. You will need to drill an oversized hole to accommodate that subfloor screw. The angle iron will go in above that opening, spanning over the top of it with some overlap. Prime and paint the angle iron once the fit is correct.

Weld that in place at the ends of the angle iron and a few stitch welds along the edges of the top flange. Grind away the paint first in areas where the welds will be. You will need a fire watch for that as the subfloor is likely to start smoking, but I think a few squirts with a spray bottle on the wood after each weld should do the trick. Once everything is dry, prime and paint the welds.

If by chance you use an AC stick welder, my recommendation is to use 1/16" diameter 6013 electrodes running at 60 amps. If you have never welded before, get someone who has to do the job. This is not really complicated but you don't want it to be your first welding job.

I did some similar repairs a while back, the trailer is back on the road, and all is well.

[80BELLA]

Thank you Christopher for your thorough reply! I plan to remove the belly pan in front (it is sagging because almost all rivets have popped thru) and all the insulation/rodent homes. This will allow me to look at frame in front - if it looks good, I will find a welder and follow your suggestions.