Matt21

So im about to et into patching up my rusted floor pans and need a few tips,
I been searching to internet looking at youtube videos of jobs that are already done. My few questions are, The uni-rail, i was looking around and underneath on how it was attached to the floor pan and is it welded in and how do i remove it from the rail without damaging the rail? My next question is is it ok to just throw a piece of sheet metal over top of the rusted floor pans and weld it in, will there be any ill effects or should i cut it all out then weld in the new sheet metal? Im new to this kind of project and not quite sure on how rust spreads.

67 GMC

I just had a guy do my floor pans behind the front seat left and right and the cargo area. The floor pans are available from Rock Auto but I got a guy to weld them as I don't do that. Each pan was around $60 with the cargo pan over a hundred but it makes it a lot easier if there's a lot of rot. It's unibody so it should be welded in good to the right places. Mine passed safety after it was done.

Radi

Rust will keep spreading unless you cut it all out. Covering over the rusty pans won't last long. (I'm doing mine a second time...guess why, lol) POR15 or similar helps too.
You have to cut away as much of the floor as possible then grind the remainder of the welds off of the frame rail. You won't hurt it.