Former VWDieselParts.com Forum

So I pulled up the carpet in my 1980 Caddy to check out corrosion. It seems that there is a layer of non-metallic stuff attached to the floor in front of the seats, it's painted body color (or it was, pretty much peeling off) but it doesn't seem to be metal. Anyone know what it is? I'm concerned because what I can see of the rust is around the edges and I'm thinking it might be more extensive underneath these strange things.

It's something like a sheet of tar.

Yeah, that stuff seems to harden over time and can break up. I imagine at that point it can let moisture get under and cause trouble.