Floor Pan Replacement

Q: Floor Pan Replacement

I’ve got some rusted floor pans front and rear, both sides. Going to pick up some replacements. I’m no welder, so I was just going to have a local welding shop do the job.

Any advice or do’s and don’ts? Brake lines, cables, fuel lines? Welding scars or sealant?

A: When it comes to floor pans, there are a couple different types. Most pans are designed to be dropped in and welded from the top. The rocker panel side is turned up. These are the simplest to install. All you do is use a air chisel to cut along the edge of the pan, flatten out what’s left and drop in the new pan. You can make a scribed line all the way around the pan then pull it back out and trim to 1/2″ to 3/8″ to the edge, less if your brave. Then simply just use sheet metal screw to hold everything in place and weld it up. I weld them as solid as possible and then use 3M seam sealer.

The other type has the rocker panel edge rolled down like the original. These aren’t really any harder to install (except for maybe on a convertible) but do require some welding from underneath. The removal of the old pan is the essentially the same. The biggest difference is spot welding the replacement along the original pinch weld seam. From the bottom, they look more like the originals. That is IF care is taken to hide the other seams. I try to help this out by making the repair seam that runs along the tunnel as high as possible. Don’t forget to leave holes for the seat belts.

Removal of the seat pedestal is the same for both replacement pans. I prefer to cut the whole pedestal out then try to remove as much of the old pan as possible. I suppose they could just be trimmed and cleaned and welded in place with the old pan on the bottom but be sure the original pan imprint is a very close match. Otherwise your seat may not sit level or square. Be sure to locate the hole for the subframe bolt.

As far a repair projects go, this is probably a easy as they come. even if you don’t do it perfectly, almost no one will ever really see it. If done with care, it’s even hard to tell when the car is up on a lift. You may want to search the archives. I’ve been through this process before and I believe Geoff posted some of the instructions.

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