I am replacing the floorpans on the 1976 Vette I got that sat for 9 years before I picked it up. Seems water leaked in because of ill fitting side windows and sat at the lowest point of the floor (floorpans and seatbelt recesses).

Anyways my question is how do I get around the door sills that seem to be laminate. Also if anyone wants to give me some hints and suggestions or instructions please feel free. I couldnt find any good posts on here or on the internet on installing floorpans so just go for it.

 

You will need to cut the fiberglass off the sill area before you replace the floor pans. Putting the fiberglass back on the car is an easy repair as opposed to that of fixing the floor pans.

On thing you will need to take extra precaution on is the fuel line that runs under the floor pan near the sill area. On the 1976 you will have fuel on the passenger side and vapor return lines on the driver side. While cutting the floor pan out of the car is relatively easy, welding them back in can be tricky considering the proximity of the floor pan to these fuel lines. Take extra care that you do not have a leaky line and shield these lines before you weld the new pan in place.

Good tools to have to do this repair. Plasma cutter and a Mig or Tig welder.

Regards,

Willcox Inc.

 

I have two or three options as for who to weld the pans who are experienced welders. Both Mig or Tig. Unfortunately I do not have access to a plasma cutter so I will be using a trusty old grinder. Score the seam I want to cut than go to work... So I am not too worried about how difficult it would be and I planned on buying the preformed pans so they look perfect. Just wondering where I should cut the door sills at? I will post some pics tomorrow so you all can make more informed suggestions with better information. Any suggestions and help at all is appreciated. Thanks.
Paul

 

I did this job on my 76 a few years ago. To remove the fiberglass rocker channel cover, I made two cuts using a Dremel with a cutoff wheel:





There are several soft aluminum rivets that have to be drilled out. At that point, I expected to be able to lift the fiberglass off, but it's also sealed to the rocker channel with some kind of glue. I used a putty knife and gentle pulling to get it off. As long as everything was already off, I used a MIG welder to fill in all the screw holes for the sill panels since they were stripped out, then re-drilled them to the proper size.

A previous owner tried to fix the floor pans by a crummy fiberglass job:



I first made a "conservative" cut along the very bottom of the pan using an angle grinder with a cutoff wheel:



I then pulled the old fiberglass off to see how bad the damage was:



The floor pan is spot welded to the rocker channel (27 welds, according to the assembly manual). A cheap air hammer with a chisel works great. If the spot welds are still holding, use the chisel to cut around the spot welds, then grind them flush later. Sorry I don't have a picture of this part.

At this point, I laid the replacement pan in and started drawing lines to see how much of the existing sides needed to be cut. I left about a 1" overlap between the old metal and the new pan along the center hump and the back and used an angle grinder to make the cuts. I had ATF sprayed all over the underside, so I kept a towel behind while cutting and welding to catch any sparks. I had to trim some metal from the outer section of the new floor pan (about 1/2" strip) so it was the right height to mate with the rocker channel. I also had to bend the new pan a bit to get a consistent fit all the way around. I put in a bubble level and tacked the new pan in place with a MIG welder. I then went around, laying 1" beads and moving around to minimize warping.

Once the pan was in, I replaced the rocker channel cover using pop rivets and urethane sealer and filled the small gaps with Bondo in preparation for painting.

In my case, the fuel lines were already out, so I didn't have to worry about them. However, the brake line also runs along the inside of the frame rail on the drivers side, so that's something else to watch for. My car sat outside just like yours, and the metal fuel lines were leaking. If you're going to replace yours, you might want to pull them before doing the floor pan so there is no problem. I replaced mine with braided steel line, which can be done with the body on the frame.