Lorenz Posted January 26, 2022 Share Posted January 26, 2022 I have a 1986 jeep comanche x with a 5 speed and when you press the clutch in the fire wall flexes witch is not allowing my clutch to fully ingage or disengage can anyone help me figure out how to fix it ? Link to comment Share on other sites More sharing options...
Pete M Posted January 26, 2022 Share Posted January 26, 2022 pics of the damaged area? Link to comment Share on other sites More sharing options...
Lorenz Posted January 26, 2022 Author Share Posted January 26, 2022 1 minute ago, Pete M said: pics of the damaged area? Truck is on its way back from my mechanic but the damage location is at the master cylinder and brake booster Link to comment Share on other sites More sharing options...
Lorenz Posted January 26, 2022 Author Share Posted January 26, 2022 Will send damage pics as soon as the old girl is back home should be this week Link to comment Share on other sites More sharing options...
Pete M Posted January 26, 2022 Share Posted January 26, 2022 it is common for a leaky master to eat up the paint and the fuse box, but I can't remember seeing one so bad as to start affecting pedal travel. Link to comment Share on other sites More sharing options...
Lorenz Posted January 26, 2022 Author Share Posted January 26, 2022 2 minutes ago, Pete M said: it is common for a leaky master to eat up the paint and the fuse box, but I can't remember seeing one so bad as to start affecting pedal travel. Yah it's got me worried tbh hope I can fix it Link to comment Share on other sites More sharing options...
Pete M Posted January 26, 2022 Share Posted January 26, 2022 the good news is that it's just steel. you can add more as-needed. Link to comment Share on other sites More sharing options...
gogmorgo Posted January 26, 2022 Share Posted January 26, 2022 Should be able to cut a chunk out of an XJ firewall and weld it into yours. Link to comment Share on other sites More sharing options...
Lorenz Posted January 26, 2022 Author Share Posted January 26, 2022 22 minutes ago, gogmorgo said: Should be able to cut a chunk out of an XJ firewall and weld it into yours. So I should be able to take a chunk of fire wall from a 1986 xj and weld it in Link to comment Share on other sites More sharing options...
Eagle Posted January 27, 2022 Share Posted January 27, 2022 Don't forget that the XJ started in 1984. '84 thru '86 should have the same firewall -- the change was in 1987, to allow for the 4.0L inline 6-cylinder engine. Link to comment Share on other sites More sharing options...
gogmorgo Posted January 27, 2022 Share Posted January 27, 2022 Would the master cylinder section of the firewall have changed for the 4.0? I thought that was just the centre section. Failing finding a matching chunk of firewall, if you figure out where it’s damaged, it shouldn’t be a ton of work to shape something functional out of new metal. Even if it’s just a plate acting as a large washer to spread the load out. Just be careful doing that that you aren’t interfering with spacing or you might affect clutch throw. Link to comment Share on other sites More sharing options...
dasbulliwagen Posted January 28, 2022 Share Posted January 28, 2022 21 hours ago, gogmorgo said: Would the master cylinder section of the firewall have changed for the 4.0? I thought that was just the centre section. Failing finding a matching chunk of firewall, if you figure out where it’s damaged, it shouldn’t be a ton of work to shape something functional out of new metal. Even if it’s just a plate acting as a large washer to spread the load out. Just be careful doing that that you aren’t interfering with spacing or you might affect clutch throw. The clutch master is different between 84-86 and 87 and later. I had that issue when I swapped an 86 AX5 with external slave into my 87. The clutch master bolts are rotated 90 degrees between them. Link to comment Share on other sites More sharing options...
87Warrior Posted February 1, 2022 Share Posted February 1, 2022 Does your truck have a support bracket running from above the drivers side kick panel to one of the clutch master cylinder mounting bolts? This bracket helps prevent the firewall from moving around when the pedal is pressed. Link to comment Share on other sites More sharing options...
schardein Posted February 6, 2022 Share Posted February 6, 2022 On 2/1/2022 at 11:26 AM, 87Warrior said: Does your truck have a support bracket running from above the drivers side kick panel to one of the clutch master cylinder mounting bolts? This bracket helps prevent the firewall from moving around when the pedal is pressed. BINGO It's common in the Jeep CJ world to see people convert to a hydraulic clutch (factory option with 4 cylinder models), which is so much better than the stock mechanical linkage (on 6 and 8 cylinder models). What they often forget is the factory bracket that ties the pedal pivot pin into the firewall at the point where the clutch MC is mounted. It also adds convenience, as the studs for the clutch MC are made into the bracket. First pic is a late YJ bracket and an early YJ/CJ bracket (different spacing). next pic is the 86 MJ parts manual, which interestingly, doesn't show a reinforcement bracket. last pic is from 87-90 parts manual, which shows a reinforcement bracket. Can anyone confirm that 84-86 XJ/MJ had the reinforcement bracket? Link to comment Share on other sites More sharing options...
1stDeuce Posted March 17, 2022 Share Posted March 17, 2022 The '84-86 master cylinder has horizontal bolts, with a bracket (rod, actually) that goes from the outboard bolt over to the kick panel to stiffen things up, just as 87Warrior suggests above. Perhaps someone took that rod out at some point? I suppose it only helps on the outside bolt... If the firewall was REALLY rusty, the MC could flex to the side some, and that would probably eventually break the brace... The '87-96 MJ's and XJ's have vertical bolts, and the service manual image from Schardein shows that there is indeed a brace with that one too... Without it I can't see how it would live, as the lower bolt hole is on a thin strip of metal between the fuse box opening and the hole that the MC rod goes through... As I am trying to convert to the '94-96 MC and slave setup, I will have to try to find one of those brackets... No JY's near me will let me out into the yard. Totally sucks for stuff like this where I just need to have a look. This thread likely saved me from having a firewall strength issue down the road... Link to comment Share on other sites More sharing options...
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