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Wrangler or XJ power brake setup

Discussion in 'Quitters' Club' started by DanStew, Sep 22, 2012.

  1. Sep 22, 2012
    DanStew

    DanStew Incorrigible. Staff Member

    Lexington, South...
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    I have an XJ booster and MC installed in my CJ. I just cant get the thing to make pressure. It will happen but i have to pump it a bunch and i have put some much fluid through the entire system by bleeding it i do not get any more bubbles, or even that much pressure getting shot out. I bled it with the engine off. When i have the engine on the brakes will cause my engine to die. I do not feel any leaks, but when i have the engine off and push the pedal in i can hear the booster weezing. Also the MC when i got it had all kinds of black crap caked on the inside, i am guessing it was old fluid that dried. I cleaned out out as best i could with brake cleaner but i am guessing it gunked up the bore and probably is the reason i cant get pressure. Should i be looknig at anything else?
     
  2. Sep 22, 2012
    '72CJ5

    '72CJ5 Member

    Modesto,...
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    When i added my yj booster and mc (not sure if they are the same or not), it had that black stuff as well so after a lot of time with a pick and carb cleaner, i was able to get it all out and my breaks are amazing! With my engine off, i hear no sound what so ever come from the brake system. I would say that maybe its time for a new booster. Have you installed this in the past and now this is a new issue or have you just installed it and have no brakes? If you just installed it, you may need to shorten the push rod that hooks up the the pedal. Good luck.
     
  3. Sep 23, 2012
    sterlclan

    sterlclan Member 2021 Sponsor

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    is there a check valve in the vac line?
     
  4. Sep 23, 2012
    DanStew

    DanStew Incorrigible. Staff Member

    Lexington, South...
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    Yes there is. Actually there is two. I put one from a Toyota in the middle of line, then there is the original one from the xj at the booster. I am not sure if it is good or bad but I still feel vacuum when I pull the line when engine is on.

    I went to the junkyard today and out of 20 zj and xj they all had that nasty sludge in them. I will probably get a new one when it comes to that.
     
  5. Sep 26, 2012
    sterlclan

    sterlclan Member 2021 Sponsor

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    you should feel it at the booster end while running,the other end should have no leakage when off. the check holds the vac in the booster
     
  6. Oct 1, 2012
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    If you hit the brakes and the engine wants to die but idles fine with foot off the brake pedal most likely the booster is defective. Hole in the diaphragm or control valves are leaking.


    Sent from my iPhone
     
  7. Oct 1, 2012
    nickmil

    nickmil In mothballs.

    Happy Valley, OR
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    Went back and read the original post. I wonder if the m/c leaked into the booster. If so brake fluid leaking into the booster can damage the booster diaphragm.


    Sent from my iPhone
     
  8. Oct 2, 2012
    DanStew

    DanStew Incorrigible. Staff Member

    Lexington, South...
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    You are correct Nick. I did find fluid in the booster. I tried to clean it out, no idea how long it was in there. Seemed newish since i didnt have fluid in the MC for a loong time. I got a new cylinder and am going to bleed it when i can get the wife in the driver seat to push the pedal. I did notice one of the fluid circuits didnt do much for pushing fluid, could have been clogged. i hope the booster is OK.
     

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