Timmaay Posted December 24, 2010 Share Posted December 24, 2010 So I recently did the WJ brake booster upgrade which works awesome! But now I have this really annoying squeak that is coming from the pedal area under the dash. It'll squeak when you step on the brakes with a good amount of force and kind whine as you hold it there. -Quite embarrassing when driving other people. If you only step on the brakes a little to slowly come to a stop, it's silent. If you really stomp on the brakes it'll squeak as you go past that point and then be quiet. I lubed up the pivot point between the rod and pedal but it didn't fix the squeak. I also tried spraying WD-40 inside the booster boot but that didn't work either. You guys think it's coming from the booster diaphragm(s) and I just got a bad one? I really hope not. Link to comment Share on other sites More sharing options...
jimoshel Posted December 24, 2010 Share Posted December 24, 2010 How about the push rod rubbing on the edge of the hole in the firewall? Try removing the return spring, make moving the brake pedal easier, and then stick your head under the dash whiling moving the pedal. Link to comment Share on other sites More sharing options...
Timmaay Posted December 24, 2010 Author Share Posted December 24, 2010 How about the push rod rubbing on the edge of the hole in the firewall? Try removing the return spring, make moving the brake pedal easier, and then stick your head under the dash whiling moving the pedal. Return spring? Isn't that internal? Link to comment Share on other sites More sharing options...
jimoshel Posted December 24, 2010 Share Posted December 24, 2010 HoBoy...Your right. I was thinking of the old FSJ' :oops: Link to comment Share on other sites More sharing options...
mj Mike Posted December 25, 2010 Share Posted December 25, 2010 I have the same squealing sound in my MJ ?? Link to comment Share on other sites More sharing options...
Comanche County Posted December 26, 2010 Share Posted December 26, 2010 Try tightening the four booster bolts. Mine sounded like it had a loud vacuum leak under the dash after I did the swap, not exactly a squeak but almost. I tightened the booster to the firewall and that took care of it. Link to comment Share on other sites More sharing options...
Timmaay Posted December 26, 2010 Author Share Posted December 26, 2010 Try tightening the four booster bolts. Mine sounded like it had a loud vacuum leak after I did the swap, not exactly a squeak but almost. I tightened the booster to the firewall and that took care of it. Ok I'll give that a shot. Thanks. Link to comment Share on other sites More sharing options...
Timmaay Posted December 26, 2010 Author Share Posted December 26, 2010 I have now determined that the noise is in fact not coming from under the dash but from the booster or master cylinder itself. The noise which sounds more like a honk than a squeak when you listen to it with the hood open. Link to comment Share on other sites More sharing options...
Timmaay Posted December 27, 2010 Author Share Posted December 27, 2010 I found the problem but I don't know why it's doing what it's doing. What's happening is that when you step on the brake pedal with a little force and then mash it real quick the booster honks just like a goose! What seems to be going on is that the two halves of the booster are separating a little bit when you apply the extra force. You can see the master cylinder get pushed out. I'm not sure if it's the two metal halves of the booster sliding by each other causing the noise or if it's the rubber diaphragm vibrating. The two halves are not supposed to move are they?? A couple tack welds should solve the problem right? Link to comment Share on other sites More sharing options...
jimoshel Posted December 27, 2010 Share Posted December 27, 2010 It's worth a try. Just watch the heat. Remember, there's a rubber diaphragm in there. Maybe take a center punch or chisel and stake the edge over. Course, there's always duct tape. Link to comment Share on other sites More sharing options...
HOrnbrod Posted December 27, 2010 Share Posted December 27, 2010 Nope, sorry I disagree. Staking or tack welding may or may not repair the booster leak but I'd never try. Just replace it, won't break the bank. Never cheap out on your brakes mate. :cheers: Link to comment Share on other sites More sharing options...
jimoshel Posted December 27, 2010 Share Posted December 27, 2010 Nope, sorry I disagree. Staking or tack welding may or may not repair the booster leak but I'd never try. Just replace it, won't break the bank. Never cheap out on your brakes mate. :cheers: :agree: TRUE. Just got caught up in the 'Fix it" frenzy. Didn't mention anything about Duct Tape tho. Link to comment Share on other sites More sharing options...
Timmaay Posted December 27, 2010 Author Share Posted December 27, 2010 Ehh I was afraid you guys might say that. Now I need to shop for a replacement and then modify the rod, again. :wall: Link to comment Share on other sites More sharing options...
Timmaay Posted January 1, 2011 Author Share Posted January 1, 2011 So I got the replacement booster in and the brakes are silent! And I got the brake lights to be very sensitive :thumbsup: They come on with the slightest touch of the pedal. :D I really hope I don't have to do that again any time soon. :thwak: You seriously have to be a freakin contortionist to work on anything under the dash like that. Link to comment Share on other sites More sharing options...
HOrnbrod Posted January 1, 2011 Share Posted January 1, 2011 :thumbsup: Link to comment Share on other sites More sharing options...
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