New master cylinder leaves hole in firewall.

[StanfieldNC]

Installing a new master cylinder and that u-shaped cut out on top leaves a gap in the firewall. Has anybody else ran into this? What is the simplest solution?

 

[4mulas]

Foam style gasket

 

[Cuda Al]

I was not happy with this as well, didn't trust the foam gasket to keep water out as it ages, this is on a car that i know will be driven and see rain.

What I did was make a metal shim the shape of the original master and use both the fiber gasket and the foam one.

Alan

 

[Projectile Dart]

already covered above, but I was going to recommend a thin metal shim. Cut up a soda can to shape, rattle can black (or color of choice) and send it

 

[StanfieldNC]

I was not happy with this as well, didn't trust the foam gasket to keep water out as it ages, this is on a car that i know will be driven and see rain.

What I did was make a metal shim the shape of the original master and use both the fiber gasket and the foam one.
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Alan

Beautiful.

 

[StanfieldNC]

already covered above, but I was going to recommend a thin metal shim. Cut up a soda can to shape, rattle can black (or color of choice) and send it

This is pretty genius

 

[StanfieldNC]

So, here's what I did.

I took some 1/8" sticky back closed cell foam and joined it with fiber gasket material, I traced a combination of both masters and cut my own gaskets using a circular center cut instead of the diamond.

I used some gasket sealer on the master and firewall side.

All sealed up and confirmed the same under the dash. Pretty happy with the outcome.

 

[RustyRatRod]

We shouldn't have to do stupid stuff like this. The correct master cylinder is the answer. Chevy guys don't have to put up with crap like this.

 

[StanfieldNC]

We shouldn't have to do stupid stuff like this. The correct master cylinder is the answer. Chevy guys don't have to put up with crap like this.

Agreed. Not sure what else I could do here. Maybe i could have gotten away with using the old master cylinder, but this was part of the SSBC front conversion kit.

I understand where you're coming from. I'm a Mopar guy and a NY Jets fan. My hobbies aren't easy, lol.

Who here wants a dime-a-dozen Camaro or Mustang anyway? Not I.

 

[RustyRatRod]

Agreed. Not sure what else I could do here. Maybe i could have gotten away with using the old master cylinder, but this was part of the SSBC front conversion kit.

I understand where you're coming from. I'm a Mopar guy and a NY Jets fan. My hobbies aren't easy, lol.

Who here wants a dime-a-dozen Camaro or Mustang anyway? Not I.

You got that right!