C10 cab mount and floor inspection checklist
A short, repeatable inspection sequence for the areas that separate a solid cab from a structural project.
Work through these in order and write down what you find. Photograph everything before you clean anything.
Cab mounts
Look at the rubber or polyurethane mounts between the cab and frame, then at the steel above and below them. Cracked mount brackets are common and usually mean water has been sitting there.
Rocker panels
Tap along the full length with a small hammer. A dull thud rather than a ring means filler or rust. Check both sides of the inner rocker from inside the cab.
Floor pans
Lift the mat and inspect the front footwells and the area under the seat. Rust usually starts at the seam with the rocker and around the seat mounting points.
Firewall and cowl
Water entering at the cowl ends up in the footwells. Look for staining and bubbling paint on both sides of the firewall.