Floor Pan Replacement

Lessons learned:

• Do one side at a time; brace a convertible (angle iron or square tubing, dash to rear seat).
• Cut around the forward body-mount brace and the leaf-spring front-mount bracing and use them to locate the front and back corners of the floor.
• The seat support has many spot welds and must come off to reach the body-mount welds beneath it.
• Before cutting, measure from the old floor to the door sill / bottom of the rocker, and use factory holes in the transmission hump as references; leave 3–4″ overlap so you can position the new pan.
• Set the new floor over the old, scribe the edge, and cut 3–4″ below the line. Check for level often — the pan twists easily. Tack-weld in scattered spots, then seam-seal when done.

Step-by-step (one side):

1. Note the gas/brake line locations (if not a frame-off). Prime and paint the new pan.
2. Remove the seat pedestal and the rear-seat floor brace.
3. Remove the bottom of the old pan; clean the belly brace and leave the welded support pieces in place.
4. Set the new pan, scribe a line onto the old metal (sit it tight on the belly brace, screws if needed), trim ~1″ below the line, refit and recheck.
5. Mark the seat-belt, rear-subframe, and brace locations from underneath; trim to 1/2″ of the scribe line; cut the seat-belt and frame-attach holes.
6. Drill holes to plug-weld through the pan to the underbody brackets. Tack every ~4″, then fill in until welds are 1–2″ apart, then weld solid.
7. Reinstall the rear brace and seat pedestal; caulk between the new pan and inner rocker. Repeat the other side. Take your time.