The Stovebolt Site Forums The Shop Area Paint and Body Shop What can I use between sheetmetal and a stiffener plate?

I have added firewall mounted Brake and clutch pedals. The Brake pedal works fine, but the Hydraulic clutch pedal causes the firewall to flex quite a bit when I depress it. I’m cutting a plate about 1/8” thick to add as a stiffener that I will mount on the inside of the firewall. It will be held in place by the clutch and brake pedal assemblies. I’d like to put something between the plate and the firewall just so it’s not a metal to metal contact. Does anyone know of a product that I can use? The firewall originally had a layer of what seemed to be tar soaked felt. That was removed when I had the truck in a shop. It doesn’t need to be thick, thin would be better I think, and can take the heat of the firewall.

Find a crew putting on a residential roof with a complete tear off. Ask the foreman if you can have a piece of roofing felt big enough to cover the area you’re working on.

Oh, I think that will work, Thanks! I have a roll.

I wouldn't recommend anything. Weld in the plate. Any material like sound deadener or roofing felt will eventually compress and give you loose mounting bolts.

I agree with MNSmith. I replaced the inner panel on my truck with 1/8" plate, tack welded it around the edges and spot welded it using some of the holes in the firewall so it would be solid.

I cut the plate and when I test fit it I found it would not sit flush on one corner. When the restoration shop moved the steering column hole they may have left the firewall warped. I added a bolt to draw the plate and firewall together. I used tarpaper for the gasket, it is thin and I don’t think it will compress. I decided now would be the best time to paint the firewall, and also under the dash, what a chore. Now with the plate in it is solid. I think if I have to do this again, I’d cut out that section of firewall and replace it with a thicker panel.

Overthinking killed the cat.
1. There is metal to metal all over the place on a truck.
2. There was metal to metal between pedal brackets and fire wall. Not sure what problem you solved with the tar paper?
3. Don't know where the "tar soaked felt was exactly. Inside or outside? Where? between what?
4. Does your firewall get that hot?
5. No need to cut a firewall to add a thicker piece. What you did is best.

If you had wanted to have the pedal brackets mounted to the firewall metal for some reason, two or three pieces of angle would have worked also. You can't dimple like they did on the floor. Which is another way to stiffen.

I considered using some channel strips, but I'm happy with the plate. This picture shows a u-channel on the right and where the left one was removed. You can see some of the tar felt on the right inner firewall, maybe it's jute, but it was gummy.

I have that same tar like paper/felt in my ‘52 3100. I believe it was placed there for sound deadening and heat insulating purposes. Just my 2 cents!