968gene

My 94 coupe has only 114,000 mile on it and the firewall is cracked. The attached picture is after pulling everything out of the way and cleaning out the seam sealer. The small holes are from the PO's attempts to "fix" the flexing issue. He had wood screws placed from inside the fender to support the firewall. (Super Genius!) The split starts in the main harness hole, runs along the fender/firewall seam and then travels along a straight line where the pedal box is spot welded to the firewall. Short of installing a full firewall plate, there doesn't appear to be a convenient way to fix or even prevent this type of damage.

sydneyman

my clutch pedal has made a squeaking noise for my entire ownership(only about 4 years really...). Im avoiding that area on purpose... what are your plans?

968gene

i will be adding a full firewall plate. Not much choice!

MB968

The fix that a PO did on my car was to triangulate the space between the firewall, and the fender well by welding in a plate at about a 60 degree angle between the two (more normal to the firewall, and more tangent to the fender well). You might consider something like this. From a load/stress standpoint, this triangulation allows loads applied normal to the firewall by the brake/clutch to be transferred to an in-plane load on the fender well.

Another option with the holes that are already in yours, you might consider a piece of heavy angle iron between the firewall and the fender well. You'd have to use large diameter aircraft or the like shear rivits to connect the two to get a good enough connection between the pieces. Again, if you can do this right it will transfer most of the normal loads on the firewall to in-plane load on the fender well.

tamathumper

Ouch, sorry to see that! And sorry to see that you have as much "previous-owner damage" as original damage, too. I've been in that situation before on previous P-cars.

blue44

great picture, Gene, any reason you couldn't get a ( careful ) gas welder to make a connection along that fender ? Donn

968gene

Careful welding will fix it however the original weakness will still be there. The combination of pedal box, clutch master and firewall combines for a triple wall thickness-except where the crack happens. So my plan is to add a firewall plate so that the single thickness areas are doubled up.

JimV8

I'm just at the point of putting a CNC Master Cylinder on and removed the sealant between the fenderwell and the firewall. Agree that a weld bead would help but that won't solve the flexing that originates at the outside mounting stud. The CNC mounting holes are slightly larger than the OE so I might go north/south and strengthen those areas with a 16 ga plate

968gene

Here is a shot from the inside. You can clearly see the three layers of sheet metal that combine for the pedal box/clutch master/firewall combination. There are probably configurations to repair from the inside as well.

MB968

Great pics. Thanks for posting them. Gives me a much clearer picture of the area.

Grandpa#3

Hi Gents, Check out the repairs done on page 3 post 33 of the link below.

https://rennlist.com/forums/924-931-...acked+firewall

Cheers,
Larry

FlatSix911

Here is the direct link: https://rennlist.com/forums/6667510-post33.html

MB968

That's actually the repair on my car. Didn't know there were pics of it on here. Bought it from Rich about 18 mos. ago so he could spend a few more $'s on his 944 track car. Repair seems to be working.

Gorodn Rankin

JimV8.. Did you do this repair and if so are there any PICS and instructions, help?

JimV8

It's a work in progress. I did fabricate a plate and cleaned the area but I don't have the CNC Master yet and thats needed to make sure I have proper clearance and correct pitch angle. I'll update as it progresses.