Rear Cab Corner Replacement - Fill with Fiberglass

[duramax55]

personlay would just make sure it has a good coat of primer paint and leave open or at least have it so it can be open. Once filled if any moisture gets in, and it will it will rust faster because it cant dry out. yes those trucks rusted in the corner as most other old trucks but they were driven in mud ,dust ,rai ,snow etc. remember they are 65 years old. Fixed right it will be a long time before you see rust there again