I had a large rust spot in my firewall, and I used a die grinder to grind it out and the rust penetrated really well. Now I have a small crater in my firewall. I painted over it for now, just to have it covered, but I want to repair it before I sell the car.

The firewall appears to be made of layers of metal, or is it just one big thick piece? How would I go about repairing this? I was thinking of just filling the whole hole up with weld, grinding it down, and bondo'ing it smooth. Or should I Por-15 the inside, and just weld a patch panel over it? Filling it with weld would be a better repair, can anyone think why I can't do this?

Has anyone done this before?

Mathius

 

No one wants to chime in here? I thought Fatal88 replaced his whole firewall with a 4th gen one? Does anyone have any information on this?

Mathius

 

A firewall is multi layer sheetmetal.

As for repair, some of it depends on your skills, how big this spot is, how much time money you want to invest.

Everyones opinion of "correct/proper" is going to be different.

I would say if its a spot larger then half-dollar size, cut it out, weld new piece in.

Smaller then that, the weld it shut, fiberglass over it should be fine. Then I would get some rubber undercoating and spray back over it. Do same on other side to make it look "even".