I was troubleshooting some weird clutch behavior on my wife's 968, and not having a lot of success. While under the car, bleeding the slave cylinder, I noticed a lot of movement from the hose as she tested the pedal. I got out from under the car and watched the master cylinder as she again pushed the pedal. Yep, the whole cylinder moved as the firewall flexed along a crack.

I read on the board that some of you had tried a reinforcing plate on the inside of the car. Looking under there, I can not imagine the amount of work to get that done, all the while laying on your back in the footwell! I didn't think I could manage that, so I came up with another solution.

I fabricated a small but stout brace that ties the MC (and therefore the flexy firewall) into the wheelwell. Perhaps not the prettiest solution, but it works really well. Hope this can help others!

 

Very nice. Sure beats removing everything, grinding, welding and painting.

 

Greg, how strong is the wheel well sheet metal in that area? It is scary to see how much the firewall flexes when the clutch is depressed. It becomes a big problem on cars that have heavy duty or stiff clutches.
Raj

 

i have seen this before.

i made a reinforcement place for it and weld it, a lot of work to make a neat repair of that problem.

 

I am sure that will hold up another 40k miles.

 

Raj:

The sheet metal seems pretty strong here. Better yet, you can see that there is a formed ridge around that area, which should give it good stiffness.

 

Are you sure it's just the spot welds between the wheel well and firewall that have cracked? Mine allowed enough flex to begin cracks between the steering column, brake and clutch holes. With all the stuff in there it's a bit difficult to see, but make sure you don't have anything else going wrong in there.

 

I think I won't wait until it happens.. might be good idea to install reinforcement before the firewall actually breaks.
Thanks for the tip!

Jarmo

 

I was thinking the same thing. Scary!

 

Thanks for posting. That might not be a permanent solution (idunno) but it will surely help greatly and work for a long time.

 

I had the exact same problem on my 951. I ended up pulling out the wiring harness in that area, fuse box panel, clutch hydraulics and a fellow rennlist member came over and welded the seam for me and the cracked sheet metal. I grinded it down and painted back over it, almost looks factory now. I was pretty bummed out about it, but its been about two years now and there are no problems in that area now. I will try to find the pictures and post them up.

BTW- Mine had cracked along the seam where the firewall meets the shock tower area right under the clutch master cylinder, and cracked the metal up to where harness comes through the firewall in front of the fuse box.

 

Thanks, Chris - as far as I can tell (and it's hard to see down in there) the problem is small and local. The crack formed between where the MC mounts and the large hole for the wiring harness. The flexing doesn't appear to have affected the steering or brakes.

 

This is a great idea. I may be doing the same to my car in the near future. It looks plenty strong as far as the sheet metal goes as it is mostly in shear. The bolt and bracket should be taking most of the load with a small moment load on the sheet metal.

 

The bracket really needs to be triangulated so that it wont bend over time. This is one I made up to help someone else out in a pinch. Same idea that is on your car but it won't bend over time because of the bends. Now the hard part is trying to find someone that can duplicate the bracket so others can benifit from it.

 

Nice work Max!