Originally Posted by Chetcpo

'85 300D rust carnage. I was warned by a forum member to check that seatbelt mount after posting a pic of the rusty door sill.

I have since repaired it. I bent up and welded in some 16G steel which is welded to a captive nut. I sanwiched that to a piece bolted and welded to the floorboard and welded to the exterior rocker panel. I then filled the hollow rocker section with expanding structural polyeurethane foam (think gorilla glue by the gallon) and then fixed the rusted out sections of the rocker that let the water in in the first place. Not the best repair, I really wanted to replace the floorpan and rocker, but effective and fast nonetheless. All of this seems to have happenned because the PO left a plastic plug out of the back of the rocker panel in the rear fender well and let water splash in. The rocker and floorpan on the other side was intact.