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Brake Problem Looking For Hint

Discussion in 'Intermediate CJ-5/6/7/8' started by johneyboy03, Aug 8, 2019.

  1. Aug 8, 2019
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
    Joined:
    Jan 15, 2011
    Messages:
    2,115
    ok Guy's i'm trying to find a problem on my brake.

    I have front and rear dana 44 with all four corner caliper from a chevy K15. I have great stopping power, there isn't a problem. (i can lock my 35" a 60 mph's)

    I have bleed everything a numerous amount of time, and i still get about 1" of free play on my brake pedal.
    When i'm going to town (around 6-7 miles trip each time), my brake pedal loose the free play and became hard, but i still have a very good braking power. I can sense some drag but it's not one side, i feel something is braking the jeep. I dont touch the steering and i can feel the drag but it stay straight.

    Last week-end i've done a 120 miles trip (60 miles go and 60 miles to go home with a 3 hours not moving between). I had that problem with the brake on the 10 first mile, has the sympton described above and then it come back to normal (1" free play on brake pedal) for the rest of the trip. It did exactly the same on the return trip.

    I did change the brake bad, pin bushing about 2 month ago. I had one caliper that i have a hard time getting the piston back in.

    Don't know where the problem is, made some research on different forum but now i'm up posting my problem here.


    Maybe someone will have a hint on this problem....

    67823781_897552460602296_6809635145608331264_n.jpg
     
  2. Aug 8, 2019
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
    Joined:
    Aug 13, 2015
    Messages:
    6,656
    Do you have the correct (2psi is it for discs?) residual valves front and rear? It sounds like you have a bit of a drag, and it’s heating up the fluid, expanding it. As it cools after you park, it shrinks and releases.

    When you get home, crack a bleeder front and back while it’s still hot, see which one spurts more fluid out. You’ll at least have a better direction to start looking.
     
    47v6 likes this.
  3. Aug 8, 2019
    ITLKSEZ

    ITLKSEZ Hope for the best, prepare for the worst

    Liberty Lake, WA
    Joined:
    Aug 13, 2015
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    6,656
    Come to think of it, do you have enough free play at rest? When the plunger is all the way out, I think it’s supposed to open a valve to allow any back pressure to escape into the reservoir. Like, when you do a brake job and compress the pistons and it over-fills your reservoir and spills everywhere... :mad:

    If it’s not adjusted correctly at rest, that valve might not be opening, and it could be feeding that pressure into your pedal.
     
    45es likes this.
  4. Aug 8, 2019
    Howard Eisenhauer

    Howard Eisenhauer Administrator Staff Member

    Tantallon, Nova...
    Joined:
    Nov 22, 2003
    Messages:
    8,102
    My assessment exactyl- if the plunger doesn't come all the way back the fluid can't escape back into the reservoir.

    If there is free play in the pedal when cold it could be a sticky piston in the mc.
     
    45es likes this.
  5. Aug 8, 2019
    Lockman

    Lockman OK.....Now I Get It . 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Silver Hill,...
    Joined:
    Dec 4, 2018
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    2,698
    Could Be the MC as Howard said , or did you install a Proportioning / Metering Valve for disc brakes ; Front & Rear ? ..... You need the proper pressures like Ryan said.
    proportion-valve-pv2-1.jpg
     
  6. Aug 12, 2019
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
    Joined:
    Jan 15, 2011
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    2,115
    Yeah, seem to be the proportioning valve. It's look like a valve from a wrangler jeep yj with the rear drum. So it make sense that it come to that. From my logic, the 10 psi residual let too much pressure on the rear brake, and as itlkez said it built up heat so more pressure come in....

    So another thing to do in the infinite list ahah

    thank you for help guy's
     
    Muzikp and ITLKSEZ like this.
  7. Sep 9, 2019
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
    Joined:
    Jan 15, 2011
    Messages:
    2,115
    Just remind me something....when i change the master 3 years ago, i have a hard time dealing with the booster pin dept. So having time to kill last week-end i put the rear axle on stand. I had a hard time turnig the tire. i decided to unbolt the master from the booster and it litteraly free up the rear wheel.

    From there i may have try 5-6 ajustement but it's really hard to set-up the length of it. I dont have the right tools and it's a little bit pricey.

    Little turn (about 1/4 turn at the time) can make a huge difference in the pedal softness....does anybody have some tricks to have the brake set up correctly without the right tool ?
     
  8. Sep 9, 2019
    45es

    45es Active Member 2024 Sponsor 2023 Sponsor 2022 Sponsor

    Naches, WA
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    Not sure what you mean "right tool". You want approximately 1/16" clearance between end of booster rod and master cylinder piston. You can measure the depth of master cylinder piston from the mounting surface and stick out of booster rod to calculate the amount of adjustment needed. If the booster push rod is recessed in from the M/C mounting surface, have someone step on brake pedal to push rod out to access and adjust it.
     
  9. Sep 10, 2019
    johneyboy03

    johneyboy03 The green beast

    Quebec, Canada
    Joined:
    Jan 15, 2011
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    2,115
    I did use a galiper with a sqare yesterday and was able to set it up correctly, still need to do a road test.
     
    45es likes this.
  10. Sep 11, 2019
    cj6/442

    cj6/442 Sponsor

    Fallbrook, Calif
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    Feb 6, 2008
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    I talked to Wilwood and they said no 2 lb valve was needed. I still run the frame pedals .
     
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