75' Sovereign 31 - Replace subfloor with belly pan on?

[olgie]

I am restoring a 1975 Airstream Sovereign 31 and need to replace the rotten subfloor and make necessary repairs to the chassi. Is it possible to do this with the belly pan AND shell on? I want to avoid removing the bellypan if possible and work from within the trailer interior to lift up the floor, clean up the bellypan and make any necessary repairs to the frame. Then of course put the subfloor back in.

Photo attached is where I am at.

ALSO what is the best way to remove the large subfloor bolts - I was told a hole saw & impact driver.

Thank you!

[olgie]

here is the photo

[dbj216]

Hello from Colorado: I have a 75 Overlander 27', two sizes shorter than your top of the line Sovereign. I have the belly pan down now. I'm repairing the rear floor rot and rear end separation as well as installing new waste water holding tanks. Maybe my project thread will interest you.

I highly recommend you drop the belly pan to replace the subfloor. Gutting the interior is the hard work, the belly pan is easy. The belly pan is cheap aluminum, likely corroded and needing replaced anyways. But most importantly it will give you access to the outrigger bolts, elevator bolts, drain water plumbing, some wiring, and a bunch of other stuff. You can also thoroughly inspect the frame for cracks and buckling, a problem in the longer 70s trailers like ours. You might even get all ambitious and clean and paint the frame to help prevent future rust.

Just plan on placing your trailer on very sturdy jack stands about 20" (45 cm) off the ground. I use a mechanics roller to scoot around under the trailer. I have worked on gravel before by laying on a piece of old carpet. Drill out the old rivets and let the belly pan drop. Get ready for some really dirty insulation to fall in your face. You will wash up just fine. It will cost about $400 for replacement belly pan aluminum.

Once the belly pan aluminum is down, you can grab the elevator bolts (actually screws) from below and "wiggle" them until they break. They you can just push them up and out. The hole saw method works too, it is just more work than "wiggling" them back and forth.

You can replace the subfloor without lifting the shell. You will need to mostly release the body (shell) from the frame, but not from the "F shaped aluminum channel" between the exterior and interior skins. You will have to gently lift the body just a bit in order to slide a new piece of plywood subfloor in place. I think some folks slide in the new plywood from the outside.

You will likely get more advice from folks who have actually done what you want to do.

David

[TheGreatleys]

Yes, it is possible to do what you're suggesting. It's the hard way, though. Removing and replacing the belly pan is easier than trying to do frame repairs with the belly pan in place. If outriggers need repair, there's no way to avoid it.

Vintage trailer supply sells floor screws that you can install from the top without access from below. I agree, drilling out the elevator bolts with a hole saw is a good way to go.

I say go ahead and remove the areas you want to replace and get a look at the frame. Once you see what's down there, you may decide to go ahead and drop the belly pan.