Firewall & master cylinder don't match?

[ValiantOne]

The car: 68 val
Original brakes: 9 in drums on all 4 corners
Upgrading to: front discs and larger rear drums

I never paid attention to the way the old (drum only) m/C fit the firewall, but with the new disc brake m/C the flange that bolts to the firewall just BARELY covers the cutout in the firewall for the brake rod.

Anyone ever encounter this? Did you do anything about it?

I am concerned about possible water leaks. I thought about making a sheet metal "washer" to go behind the M/C and smoosh a larger homemade gasket against the firewall. But thought I'd ask if anyone else encountered this and solved it first.

 

[MOPARMITCH]

I'm making the same brake change on my GTS. Just looked at it and see the same thing you are talking about. I have a paint gasket kit laying around here. I just looked and I have what looks to be the thin paper gasket for the drum application with the oval cut in it. It covers outside the oval just a little. I am going to put that thin one on first and add the foam one for the disc set up. Looks like it will seal fine. If you don't have a gasket set, get one.

 

[mopowers]

I am concerned about possible water leaks. I thought about making a sheet metal "washer" to go behind the M/C and smoosh a larger homemade gasket against the firewall. But thought I'd ask if anyone else encountered this and solved it first.

Not sure if this is the same issue you're having, butt this is what I did. I used a piece of 1/8" aluminum and sandwiched it between the MC and the firewall. There seemed to be a small void on the top part of the new disk brake master cylinder where light was shining through. You can see this in the picture. I didn't like that. It's much better with the homemade "washer" to close things up and seal everything. I used the master cylinder for a template.

 

[ValiantOne]

Not sure if this is the same issue you're having, butt this is what I did. I used a piece of 1/8" aluminum and sandwiched it between the MC and the firewall. There seemed to be a small void on the top part of the new disk brake master cylinder where light was shining through. You can see this in the picture. I didn't like that. It's much better with the homemade "washer" to close things up and seal everything. I used the master cylinder for a template.

Yeah that is the problem. And the fix I was envisioning too. Hey, great minds........

Thanks Evan

 

[mopowers]

Yeah that is the problem. And the fix I was envisioning too. Hey, great minds........

Thanks Evan

No prob man. You can barely tell from the picture, but I also made a gasket from some thin foam packing material I had laying around and put it between the washer and the firewall. Goodluck and keep updating your build thread.