[Cloud9...68]

I've talked and asked about this at some length in a couple of other threads, but since it's become more of a potential problem as our cars age, I t so we could collect peoples' experience in one thread. Is there a universally accepted method, or are there a few alternatives? What's a reasonable price for the repair (I was quoted $2000)? Just looking for ideas. Thanks.

Partial Post: Please Login or Register to read the full post.

[mefforddk]

I suspected that I might have a craccked firewall. I just confirmed it, ugh. I know Flash had mentioned in a thread that he was working on a fix for cars with cracked firewalls. I know he has a device to prevent the cracking. Mine is cracked where the firewall intersects the fender well.



My thought is that his device would greatly help hold the firewall from moving also. I was thinking of trying that along with forming a piece of metal to fit on the fender well that jams up against the fire wall to prevent the interface from moving. Then I weld the metal to the fender well and avoid the critical wiring and plumbing in that area. Thoughts?

Partial Post: Please Login or Register to read the full post.

[Cloud9...68]

Based on my experience, I suspect a lot of people have cracked firewalls and don't know it. Mine was probably cracked for years. I highly recommend that everybody have someone press hard on the clutch and brake, while you look under the hood at the firewall to see if it is flexing. A broken one could be a real safety hazard.

Partial Post: Please Login or Register to read the full post.

[Kim]

I had a piece of threaded stainless steel attached from the firewall to the back-top of the strut tower. Very non-obtrusive and really hard to even see without looking for it. Welded in place at both locations. Did that 3 years ago and no issues since. Cost was about $150 at Porsche dealer.

Partial Post: Please Login or Register to read the full post.

[Cloud9...68]

Kim,



Was your firewall severely cracked prior to the installation of the piece you describe, or did you do it a preventative? Any chance of getting a picture of your fix, or is it too hard to see behind all the stuff on and in front of the firewall?

Partial Post: Please Login or Register to read the full post.

[mefforddk]

That sounds like an interesting fix. I was rethinking about a couple of pieces of angled metal that could be welded at the fender well and act as a stop. Then follow the remaining seam with 3M 2216 epoxy. However Kim's idea of a threaded rod, maybe shaped some what like a "T" could be wedged against the seam and bonded to prevent is from slipping, then weld the other end to the shock tower.

Partial Post: Please Login or Register to read the full post.

[flash]

the problem with a solution like that is that it is only going to then stress the shock tower - you would need to have a fairly stout brace so it doesn't bend, and contact area sufficient to handle the stress and spread it out - that is a pretty large surface area - otherwise, it will rip the sheet metal you attach it to



that's why the brace i came up with attaches as it does - the one for the curative measure has to be a lot beefier than the one for the preventative measure, which is already .090 thick steel



i should have one going in a couple of weeks, as i have to get some other stuff made soon anyway

Partial Post: Please Login or Register to read the full post.

[Cloud9...68]

Flash,



To clarity (and I know every case is going to be different, so it might be difficult to make a blanket statement), do you expect that the existing crack in a damaged firewall would have to be welded prior to installing your new brace? Thanks.

Partial Post: Please Login or Register to read the full post.

[mefforddk]

Flash,



Yeah I agree the area of the attachment point on the shock tower has to be large enough to spread the pressure out. Do you have any idea of the force that the clutch master cylinder places on the firewall? I would guess what ever the fluid pressure level is in the clutch line during depression is the force on the wall? Then we know how much force is being transfered to the shock tower and can design a mounting pad with margin to compensate. I certainly don't want a small rod poking into the shock tower.

Partial Post: Please Login or Register to read the full post.

[Kim]

My firewall cracked such that I could not depress the clutch pedal enough to change gears. I will take a picture of the top of the fix but the bottom part is simply too far down to see. Seemed like a cheap fix at the time that has worked well since I had it done. I don't race the car through. My car is just for commuting to work.

Partial Post: Please Login or Register to read the full post.

[94SilverCab]

I installed the firewall brace as soon as it was developed, seemed like good insurance, and I'm feeling a lot smarter after reading these posts.



A bit OT, but if you haven't installed the new(er) D1R brace for the A/C compressor and steering tensioner you WILL be writing about it at some point.



I figure that D1R/RSB modifications will save me thousands on parts I will never need to replace (S/S clutch hose).



Regards,



Jay

Partial Post: Please Login or Register to read the full post.

[Kim]

My problem pre-dated all of these new solutions. At the time it was either that or try to weld the firewall. That just seemed to be a very expensive undertaking. I am happy with my solution.

Partial Post: Please Login or Register to read the full post.

[flash]

the variance in damage between cars is the issue that will help determine the appropriateness of any given solution - one with slight damage could be repaired with a simple brace - one with more damage would need a beefier brace - one with significant damage may need welding and a brace



the type of pressure plate will also factor in - a true OEM plate won't need much - the cheap copies that many parts vendors sell will need more - a stiffer rated plate will need even more



i should be able to get a prototype knocked out in a couple of weeks, and then i can test it for pressure rating - in the meantime, if i had to guess, i'd say the system probably applies about 1000 lbs of force to the sheet metal at full load

Partial Post: Please Login or Register to read the full post.

[mefforddk]

Well here is what I did for a temporary fix. I put a deep well socket over the bolt on the master cylinder and fit an extension up the the connecting fastener on the strut brace. I got my clutch back and shifts great again. I can't beleive i have lived with that for this long. I guess the point is that a hefty piece of al or steel rod bridged between the firewall and the strut brace is strong enough. I'll monitor to make sure no extra strain is put on the strut brace bracket. This is basically a beefed up version of Flash's preventive solution.

Partial Post: Please Login or Register to read the full post.

[rkeysor]

My garage found my firewall crack when I asked them to check the clutch adjustment. I had been having a problem with the clutch pedal returning slowly when shifting out of first gear and had no suspicion of the cause. Thank God the problem was found before the firewall failed. Ultimately, I removed the inner wheel well liner and drilled two holes for bolts that went through the ends of a strip of steel, maybe 1/8" thick by 1 1/2" long adjacent to the clutch cylinder inside the engine compartment. I then worked a heavy hose clamp around the clutch cylinder so that I could draw the cylinder toward the near wheel housing (it was torquing toward the engine). I should mention that my firewall appeared to be cracked around the base of the right side (looking rearward) clutch cylinder bolt boss from from say 3 p.m. to 6 p.m. Before drawing the clutch cylinder back in position to close the break, I coated the crack with JB Weld. I then tapped a wooden wedge between the brake booster and the clutch cylinder to push it back into position and to hold it while the JB Weld cured. I also then tightened my hose clamp and the two bolts holding it against the inner wheel well to pull the cylinder in the same direction. Upon completion, I found that the cylinder no longer torqued to the side, but pushed slightly toward the front of the car with application of the clutch. I decided to stop this by putting a blocking mechanism at the front of the cylinder, where the braided (on my car) clutch slave line exits. I took an old open end wrench that fit the locking nut on the clutch hose, cut off about 1 1/2" of the end that fit the locking nut, drilled a hole through the stub, cut a section of husky angle iron, drilled and tapped that for the bolt that goes through the wrench remnant, positioned the wrench over the hose locking nut and tight against the front face of the clutch cylinder, and then put a bolt through the fender well and through a predrilled hole in the piece of angle iron. I know this sounds crazy, but my clutch cylinder isn't going anywhere. If it wasn't such a chore bleeding the damned clutch slave, I probably would have disconnected the hose, cut a box end wrench, and fitted that over the front of the cylinder (after replacing the hose, of course). Incidentally, installing the hose clamp devise proved very difficult--anyone who has examined the problem of getting to the clutch cylinder will understand how hard it is to work in this area without disconnecting the plethora of air conditioning and other lines. The second fix, surprisingly, wasn't that difficult. I went to this trouble after trying to reach the firewall from inside the cockpit--first removing the seat--and finding I couldn't begin reach the problem. And reading that someone had spent $2,000 for a proper fix was kind intimidating financially. Oh yes, I also left in place the wooden wedge mentioned earlier.I know this is kind of jackleg, but I enjoyed the challenge.

Partial Post: Please Login or Register to read the full post.

[Cloud9...68]

Wow, some innovative solutions. My clutch also would sometime stick a bit, rather than crisply moving back to the top position after I released it. I thought it was due to a fork alignment issue that I would get to eventually; little did I know what I was up against. As I said earlier, I suspect a lot more people have this problem than they're aware of.



However, I still can't find the gash. How much stuff has to be removed before it can generally be seen? Do I need to remove the black plastic cowl just in front of the windshield in the engine compartment? I tried to look for the gash from below, but still no luck. There's just so much stuff on and in front of the firewall, that I'm having trouble getting a clean view of the firewall from any angle. I just started the clutch/flywheel/rear main seal R & R, so I'll keep poking around while I'm under there. Not that I'm in any huge hurry to find an ugly gash in my firewall...

Partial Post: Please Login or Register to read the full post.

[flash]

usually you can see it right away, immediately below the stud on which the cylinder is mounted

Partial Post: Please Login or Register to read the full post.

[968LS1]

Have someone depress the clutch while you look at the clutch master you should see it move and that will reveal the trouble.

Partial Post: Please Login or Register to read the full post.

[rkeysor]

You must first remove the plastic panel that runs across the engine bay behind the engine. I think there are a couple of nut-like pieces that thread onto permanent studs that secure this panel. You thus expose the clutch cylinder, etc. To see if you have any movement in the clutch cylinder, you need someone to depress the clutch pedal while you are viewing the cylinder from above (after removing the panel). Earlier a member related how he basically replaced everything right down to the clutch itself before finding out that a failing firewall was real problem. Everyone should make this check. It costs nothing to look.

Partial Post: Please Login or Register to read the full post.

[Cloud9...68]

"You must first remove the plastic panel that runs across the engine bay behind the engine. I think there are a couple of nut-like pieces that thread onto permanent studs that secure this panel. You thus expose the clutch cylinder, etc. To see if you have any movement in the clutch cylinder, you need someone to depress the clutch pedal while you are viewing the cylinder from above (after removing the panel). Earlier a member related how he basically replaced everything right down to the clutch itself before finding out that a failing firewall was real problem. Everyone should make this check. It costs nothing to look."



Thanks for confirming what I had suspected; with that plastic cover in place, it's impossible to see anything on the firewall below. OK, I'll take it off and check. And you're 100% right that EVERYONE (sorry for shouting) should check their firewall. If a car like mine, which has lived in the soutern US its entire life, with a stock clutch, could have the problem, any car could. The sooner you catch it, the less expensive the repair.

Partial Post: Please Login or Register to read the full post.