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Cracked Firewall Repair?

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Old 05-06-2009 | 03:28 AM
  #16  
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I fixed squeaks using lithium grease spray... just a couple of tiny squirts into the pedal pivot and now it's quiet.

OK, so that little L-bracket actually stops all the flexing from a cracked firewall? So aside from aesthetics, why is welding in 2 plates better than the L-bracket? Is there an actual write up for this? I mean I understand it's just drilling a hole, but is the hole drilled from the engine bay or from the wheel well, or what? And do we use reinforcements on this new hole we drill?

Mike C, your ideas sound great but I didn't understand what you're saying. What is a u-bolt, and did you put your 1/8" thick plate in the engine bay side or the cabin side?

EDIT:
Never mind Mike, I just came across your old post.
And a write up by nkgosselin. He drilled from the engine bay side down through to the wheel well, but his bracket was several inches long. For those little L-brackets, is there still enough room for a drill from above?

Last edited by FRporscheman; 05-06-2009 at 04:16 AM.
Old 05-06-2009 | 12:42 PM
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Originally Posted by V2Rocket_aka944
ok so its not a common thing on NAs..

what would cause my clutch pedal to squeak when i press it?
A cracked firewall can cause this. I was getting a minor squeak about a year ago, and now it's clearly audible and the firewall is definitely cracked.

Originally Posted by MPD47
Both of my past 951's had the crack. One of them got fairly bad and we patched it as a temporary fix (lined the metal up and just filled it). Certainly the proper way is reinforcement plates on BOTH sides of the firewall.
If you do this, how can you get the master cylinder on? Wouldn't the clevis have to be really long?
Old 05-06-2009 | 12:48 PM
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Originally Posted by FRporscheman
I fixed squeaks using lithium grease spray... just a couple of tiny squirts into the pedal pivot and now it's quiet.

OK, so that little L-bracket actually stops all the flexing from a cracked firewall? So aside from aesthetics, why is welding in 2 plates better than the L-bracket? Is there an actual write up for this? I mean I understand it's just drilling a hole, but is the hole drilled from the engine bay or from the wheel well, or what? And do we use reinforcements on this new hole we drill?

Mike C, your ideas sound great but I didn't understand what you're saying. What is a u-bolt, and did you put your 1/8" thick plate in the engine bay side or the cabin side?

EDIT:
Never mind Mike, I just came across your old post.
And a write up by nkgosselin. He drilled from the engine bay side down through to the wheel well, but his bracket was several inches long. For those little L-brackets, is there still enough room for a drill from above?
I drilled from above for that L bracket. The bracket is more than strong enough to hold the MC from flexing. It is a fix that will work in a pinch. Ideally, pulling everything off the firewall and fixing it correctly with a welder is the way to go, but most people are not going to take the time to do that themselves, have the resources to do it, or have that much money to pay a shop to do it properly (Ie, is it worth paying x amount of $$ to repair it properly....this was a $500 SPEC car, so the answer was no, lol). If it was a concourse car, then everything would have been removed and a more cosmetic fix would have been employed.
Old 05-07-2009 | 01:38 AM
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Thanks Doc! I'm curious about the longevity of the bracket fix. You say it works in a pinch and is much cheaper. But I have my own MIG welder, I've been a part time mechanic for a few years, and I have a ton of tools and space. Let's also assume that I have time (which I probably don't but let's say I do).

Will the L bracket hold? Or will it eventually fail, or cause other failures like the spot welds at the firewall/wheel well interface?

If the bracket is a robust fix then even if I have time, space, equipment and skill, I would shove them all and stick to a 10-minute bracket and watch TV the rest of the day.
Old 05-07-2009 | 02:58 AM
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Gabe just repaired mine when he had my car. Perhaps he will chime in on exactly what he did. I think they took a plate and welded it in but, honestly I just don't remember.
Old 05-07-2009 | 07:05 PM
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Luis, however you end up repairing it, please let us know and show a pic or two.
Old 05-08-2009 | 03:34 AM
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I'm about 12 hours away from welding. I just discovered I have to pull off my intake manifold to pull the brake booster out. And I haven't figure out which side of the firewall I'm going to pull the wiring harness to before I start welding... but I'm almost there.

Pics to come.

(PS, I hate working around the pedals, I think Porsche should pay my chiropractor bills.)
Old 05-08-2009 | 11:13 AM
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Well, since this is a somewhat unique car I decided to take it to the Porsche dealer to let them freak me out, and freak me out they did, with a ballpark quote in the neighborhood of € 3,000 for the repair.

They haven't sent me the final quote yet but I'm going to pass, most likely, as it's a pretty outrageous amount I think.

They justified it by saying that there are many mechanic hours involved in taking everthing apart for the welding and then to put everything back together.

I'm quite discouraged, to say the least, as I lack the facilities or equipment (not to mention welding skills) to take something like this on myself, but since this is not a daily driver, I plan to take it to the other OPC in town to see if their quote is any different. I believe their bodywork is subcontracted to another shop that does quality work and might come in below this first dealer.

If that fails, there's an aftermarket shop that I used to do the clutch on this car because of the gazillion hours involved, and I'll go to them again to see what they say. Will update the thread depending on what I decide to do.

Originally Posted by Rich Sandor
I'm about 12 hours away from welding. I just discovered I have to pull off my intake manifold to pull the brake booster out. And I haven't figure out which side of the firewall I'm going to pull the wiring harness to before I start welding... but I'm almost there.

Pics to come.

(PS, I hate working around the pedals, I think Porsche should pay my chiropractor bills.)
Good on you for taking this on yourself! I applaud your courage. As for me, I just saw my car and the OPC removed the booster and master cylinder leaving the manifold on. In fact, I was pretty impressed with how little they took apart to properly assess the damage to the firewall.
Old 05-08-2009 | 11:37 AM
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Luis,

How about Doc's proposed fix? If you don't have the facilities to undertake this yourself, print it out and take to some independents and see what they might quote to do it... looks like a respectable fix to me!

Last edited by Mark944na86; 05-09-2009 at 05:31 AM.
Old 05-08-2009 | 12:16 PM
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Respectable, yes, but unfortunately this is the turbo cab and I'd like to keep it in as near stock condition as possible, so I'm stuck with getting the full repair done.
Old 05-08-2009 | 04:04 PM
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Originally Posted by Luis de Prat
Good on you for taking this on yourself! I applaud your courage. As for me, I just saw my car and the OPC removed the booster and master cylinder leaving the manifold on. In fact, I was pretty impressed with how little they took apart to properly assess the damage to the firewall.
Yea on the 968, you have to remove the intake manifold to get the booster out. Seems like the one job that's more laborious than the 951.

Although you don't have to remove much to SEE the damage, you should remove everything within the vicinity when welding. The last thing you want is to overheat any nearby wires and melt them together inside their harnesses. That would make for a nightmare later on when you're trying to figure out why the engine is cutting in and out.
Old 05-08-2009 | 05:30 PM
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Luis, I am about to write you an email right now....

For everyone else as well I will chime in about my repair process when I get a spare minute. I just moved and haven't set up my own computer that has the repair pics etc.
Old 05-08-2009 | 11:22 PM
  #28  
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I drilled the holes for the u-bolt from underneath the fender well. There wasn't enough room to get the drill in from above.
Old 05-09-2009 | 06:49 AM
  #29  
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Colin, thanks so much for the email. I replied and look forward to the photos when you get settled in your new place.
Old 05-12-2009 | 05:30 PM
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Default 968 Firewall crack repair

Booster is removable with intake manifold installed but not easy. As I recall, motor mount must be removed and engine dropped down on drives side to even begin getting the booster out.

Mike



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