Cracked firewall around the clutch MC

The firewall sheet metal where my Clutch MC is mounted on the firewall has fatigued and cracked, to point of being a major safety risk. I need some ideas on fixing it. I am wondering if a thick steel plate on the wall inside the cab might work? Under the hood side, does not look like a good option.

Is there any other option, thinking outside of the box?

I would hit the J Y and cut out the affected area to use under the hood then use some plate inside just make sure the inside plate is larger than the under the hood plate so it will take all the stress.Also I would either weld it in or use some good glue to hold it in placeinstead of relying on the factory 4 bolts.

It is only 2 bolts holding on, in a BAD location!

I loaded some photos:

muddypunk said:

I would hit the J Y and cut out the affected area to use under the hood then use some plate inside just make sure the inside plate is larger than the under the hood plate so it will take all the stress.Also I would either weld it in or use some good glue to hold it in placeinstead of relying on the factory 4 bolts.

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I seriously doubt I can find a clean 85 4 banger to use. It is 2 bolts, see the photos. The passenger side is the unreinforced side where it cracked. I agree on the inside plate needing to be larger!!!!

larger, heavier plate on inside, maybe sheet metal hamered to shape on the outside. A good adhesive and several bolts to hold it all together. Then mount the clutch cylinder.

pokeyxj said:

larger, heavier plate on inside, maybe sheet metal hamered to shape on the outside. A good adhesive and several bolts to hold it all together. Then mount the clutch cylinder.

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Thick or thin sheet metal? My experience has been that thick plate tends to move all the stress to the remaining thin metal, and just moves the crack (or the weld fails if welded with plate to sheet meta).

Those are some pretty small pics, can't quite see what's going on. I know on the later ones there is a bolted in strengthening bracket that goes from the driver side bolt to the pedal bracket assembly, I can't quite tell if you have it or not.

kastein said:

Those are some pretty small pics, can't quite see what's going on. I know on the later ones there is a bolted in strengthening bracket that goes from the driver side bolt to the pedal bracket assembly, I can't quite tell if you have it or not.

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Yeah, I think you're missing it. Not sure if they changed the master cylinder setup or not though, they might well have. If I remember I'll take some pics of how mine is set up.

The extra bracket/brace is a real pain in the butt to get lined up and installed correctly. Glad I didn't skip it, I almost did.

kastein said:

Yeah, I think you're missing it. Not sure if they changed the master cylinder setup or not though, they might well have. If I remember I'll take some pics of how mine is set up.

The extra bracket/brace is a real pain in the butt to get lined up and installed correctly. Glad I didn't skip it, I almost did.

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Thanks, I really would appreciate it if some one would post some photos, or a parts page even, showing the newer jeeps added reinforcing bracket!!!!

PLEASE!!!

There is a very large, curled on the ends, flat plate brace under the brake MC on the hood side of mine, and the crack now goes 180 degrees around the clutch MC flange and bolt on the passenger side and then straight up vertically, so there is no spot to drill a hole to stop the bottom crack, as it is following the flange of clutch MC precisely.

Then another crack runs directly from the same bolt horizontally to the brake MC brace plate, and disappears behind the brake MC brace plate.


The more I look at it I think it needs a solid brace to the passenger side bolt. Looks like there are several good places to add another brace bar.

kastein said:

Yeah, I think you're missing it. Not sure if they changed the master cylinder setup or not though, they might well have. If I remember I'll take some pics of how mine is set up.

The extra bracket/brace is a real pain in the butt to get lined up and installed correctly. Glad I didn't skip it, I almost did.

Click to expand...

Was a real small short bracket that attached to the main brake peddle bracket assy? I am looking at the extra bracket on the left side of this:

http://www.naxja.org/forum/showpost.php?p=245720844&postcount=7

Mine is missing that extra piece on the left side, extra bracket, and I can image it connecting a small short stiffener to the right bolt on the clutch MC.

85 Jeep firewall patch is now built, installed and working very well. IT is back to DD service

.....but

I am sad to say my right knee and leg-knee muscles went out on me, so I can not brake and clutch at the same time:tears:. So back to test driving the 87 auto, to see if the sudden death syndrome gremlins have heeded my vacate notice and moved on not. They probably just move on to my knee, Bloody Bast*rds!!!!:rattle:

Gave up my 4th rental car of the week tonight, and I am back to depending on ancient jeep technology for DD services!!!! LOL

I used about a 10 Ga steel plate on the inside, larger L x W than the old one, then I used a 10 Ga aluminum plate on the outside to make a sandwhich, added two bolts above the clutch MC to hold the plates with a 4 bolt sandwich, then added some silicone copper sealant between the plates as a water tight seal.. Looks like it will outlast every thing else, LOL.