I just bought this car and I am in process of prepping the underside of it for POR-15 and I found these holes. Somebody had already slapped on some bondo just on the bottom for a quick fix. So I removed it then removed the seat and pulled up the carpet and found this. I really don't have access to a welder right now so what would be the best way to repair this. Should I clean it with a wire wheel POR-15 it Rivet a patch and then put a fiberglass filler over that and a final coat of POR-15? THANKS AHEAD OF TIME.

 

My Trans Am is not as rotted out as yours but I do plan on patching it before I install my SFC. I am going to get some 16 or 18 gauge sheet metal and use pop rivets and 10-32 cap screws with nylocks, and a bunch of body sealer/glue. The rivets I will use to attach the sheet to the floorboard, but I will drill holes through the folded edge of the cross-member/frame and secure the sheet metal to the frame rails in those areas.

I plan on cutting out all the old rust on the floor boards and treating the rest of the floor before I drill the holes or make the patch. Then after the patch is made and the holes all drilled, I will apply the sealer/glue and bolt/rivet the patch into place.

My grandfather restored a 1965 Signet Convertible back in 1991 and he did the same exact thing when he patched HUGE holes in the floor boards of that car. Then he welded in two 1/8th inch by 1 1/4 inch "T" rails from the front sub-frame to the rear spring mounts. This totally stiffened up the car. I drove it back in 91 when it was done and it felt like I was driving a sedan... no body flex at all.

The patches lasted a good long time. I know this because my dad now owns the car and the patches are still intact and rust/damage free. Since 1991 the car has been a weekend cruiser and not a daily driver, so I cant say that your patches would last as long. But if done carefully and all the rust is removed and leftover areas treated before installing the patch, it should last a good long time.

 

Personally I would be taking it to someone to cut it out and weld in a replacement floorpan. Riveting metal over existing metal is a cobbjob.

If your not planning on keeping it forever and you dont really care, it doesnt really matter thou.

 

anything worth doing is worth doing right, you will be happier with the results and be happy you did it, besides covering rust doesnt remove the rust and it will spread.

 

I agree, take it to someone to have them cut out the rust and weld in a new floorpan, because if you just cover the rust, it will spread.

 

i had a 91 rs i only drove in the summer after i bought it, but when i removed some oft he rug for a sound sys i saw some rust, so i took the whole interior and carpet out and found holes where the frame connectors are underneath so your would have never known they where there, i put it all out and made floor pans to factory spects, welded em in perfect and ground then painted it all, your would have never knows it was fixed! sold that car for more then i payed. Fix it right its worth it.

 

I'd paint with POR-15, use POR-15's glass mesh and putty (check their web site for product info), then repaint with POR. I did something similiar, a 2 x6 section under the driver's feet, several years ago and the job shows no sign of deterioration.

JamesC

 

Patching it may not be "Doing it right" I will admit that... but it does work, it is cheap, faster to do, you can do it yourself, and if you get all the rust out, it is hard to argue with 16 years rust free since then on a weekend cruiser.

But yea, if you want it perfect, or it is rusted so bad that it is in danger of being structurally unstable, or its a winter driven daily driver, then welding in new floor boards is the way to go.

I am not going to weld in new floor boards on my TA because my car is not that bad in the floors, and it has been tied up in "body shop jail" for almost 2 years now. I just want it on the road.

When I take it to shows after its up and running, no one will be looking under my car, or the hood, not even me, I will forget its there, If the judges ding me for it, I don't really care because I will be there for the fun of it. It will be a great time with friends, family, God, and my Firebird.

That's just fine with me. I will patch it.

 

i delt with the same problem with my 91 and 92 rs now i finally bought a 85 ta that has no holes or signs of rust.... too bad it has a bad motor and trans