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Brakes

Discussion in 'Early CJ5 and CJ6 Tech' started by dkg4244, Aug 22, 2009.

  1. Aug 22, 2009
    dkg4244

    dkg4244 New Member

    Cape Cod
    Joined:
    Jan 2, 2009
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    45
    So I was driving today and my brake pedal went soft. My dad took the Jeep out for a spin about an hour before I did and he said the brakes were pretty bad. It had been sitting for a few days prior to us taking it out but I'm not sure what would cause it to go soft. The fluid level could have been low and it could have sucked air into the system because I don't see any leaks in the system at all. How do I get the cover off the master cylinder, and does anyone have any other thoughts? Thanks
     
    dkg4244, Aug 22, 2009
    #1
  2. Aug 22, 2009
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    What year? Stock? Remove the access plate on the floor and unscrew the cap on the master cylinder. Also check for brake fluid leaks at the wheel cylinders..
     
    Patrick, Aug 22, 2009
    #2
  3. Aug 22, 2009
    jasonjp62

    jasonjp62 Member

    Pennsboro WV.
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    799
    That where mine always seemed to leak before the 11' drums. At the wheel cylinders.
     
    jasonjp62, Aug 22, 2009
    #3
  4. Aug 22, 2009
    dkg4244

    dkg4244 New Member

    Cape Cod
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    Jan 2, 2009
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    It's a 59 with the stock master cylinder. I'll look at the wheel cylinders. If they were leaking, would the fluid bleed past the brake drum and drip onto the floor? My friend also said the seals in the master cylinder could be junk too since it's original. Maybe it's time for a brake upgrade.
     
    dkg4244, Aug 22, 2009
    #4
  5. Aug 22, 2009
    47willys

    47willys Member

    Austin, Texas
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    Mar 19, 2009
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    74
    Surely the master cylinder can't be 50 years old and still working-or just recently failed-could it?
     
    47willys, Aug 22, 2009
    #5
  6. Aug 23, 2009
    Walt Couch

    Walt Couch sidehill Cordele, Ga. 2024 Sponsor 2023 Sponsor 2022 Sponsor

    cordele, Ga.
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    It could be that it is by-passing inside the master. If fluid level is good then that is what's going on.
     
    Walt Couch, Aug 23, 2009
    #6
  7. Aug 23, 2009
    PeteL

    PeteL If it wasn't for physics, and law enforcement... 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Hills of NH
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    Is it soft, like spongy feeling, or is it more like a long pedal travel? If it will "pump up" until hard it could be that shoes need adjusting.
     
    PeteL, Aug 23, 2009
    #7
  8. Oct 6, 2009
    dkg4244

    dkg4244 New Member

    Cape Cod
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    Jan 2, 2009
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    Ok so the problem was the master cylinder cover has a very small pinhole in the top, allowing fluid to leak out. I filled it up and bled the brakes and everything was good. I couldn't find leaks anywhere else. Is there a way to patch this small hole, or do I have to get a whole new master cylinder? A dab of JB Weld maybe?
     
    dkg4244, Oct 6, 2009
    #8
  9. Oct 6, 2009
    EricM

    EricM Active Member

    Southern California
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    Isn't there a vent hole in the cap? Do you see alot of fluid coming out of it? You might want to pull the drums and look for leaky wheel cylinders if you don't see any other obvious brake fluid leaks.
     
    EricM, Oct 6, 2009
    #9
  10. Oct 6, 2009
    Patrick

    Patrick Super Moderator Staff Member

    Los Alamos, NM
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    That hole is the vent. It's supposed to be there.
     
    Patrick, Oct 6, 2009
    #10
  11. Oct 6, 2009
    timgr

    timgr We stand on the shoulders of giants. 2022 Sponsor

    Medford Mass USA
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    Yes, look at the brake backing plates for wetness. The fluid does not just disappear. Likely you have a leaky wheel cylinder.
     
    timgr, Oct 6, 2009
    #11
  12. Oct 6, 2009
    w3srl

    w3srl All-around swell dude Staff Member

    Port Orange, FL
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    They also do not always leak outside the backing plate, more often they leak on the inside for a LONG time before they show anything outside.

    Pull those drums ASAP IMO.
     
    w3srl, Oct 6, 2009
    #12
  13. Oct 6, 2009
    dkg4244

    dkg4244 New Member

    Cape Cod
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    Ok i will not plug that hole. Thanks for pointing that out I feel dumb. I suspect the master cylinder was low for a very long time. The PO definitley never touched it so I have no idea when it was topped off. It's still maintaining the fluid level so it's not leaking fast. I'll pull the drums off when I get home from school sometime next weekend and we'll see. Man I hate being in a dorm 3 and a half hours from my Jeep.
     
    dkg4244, Oct 6, 2009
    #13
  14. Oct 11, 2009
    cookieman

    cookieman Member

    Colton,Calif
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    if brake fluid is leaking from the vent. he has air in the lines, the air is blowing the fuild back out the vent
     
    cookieman, Oct 11, 2009
    #14
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