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Technical Brakes stick when warm

Discussion in 'The Hokey Ass Message Board' started by mcmopar, Jul 1, 2018.

  1. mcmopar
    Joined: Nov 12, 2012
    Posts: 1,590

    mcmopar
    ALLIANCE MEMBER
    from Strum, wi

    I thought i had this problem fixed last year bu i guess not. When my truck is sitting in the garage ideling and start to gets warm i notice that the front brakes grab. This is before i touch the pedal it happens. If ya let everythin cool down it spins freely. There is no problem with the rear ones.

    The front is a Heidts 4 piston aluminum caliaper. It has 4 wheel disc with 2 pound residual valves. I have checked and everything was instaled in the right direction.

    The headers are on the outside of the frame and they are wrapped. The frame does get pretty warm where the collector is. The brake line from the frame to the caliper is about 7 inches from header. Master cylinder is from speed way same as booster. I have disconnected the brake pedal just to rule out the adjustment.

    When i crack a line it is instant release of brake pressure, but i believe it is there because of the heat. I have tried beat shields but didnt want to spend to much time until i get more opinions.

    Any help would be great if ya need more pics let me know.

    Thanks Tony 20180701_135123.jpeg 20180701_135057.jpeg 20180701_135007.jpeg

    Sent from my SM-G930V using The H.A.M.B. mobile app
     
    chryslerfan55 likes this.
  2. Should be nothing that holds or "grows" pressure with the pedal released or off as in your case. How about the adjustment between the booster and master cylinder.
     
  3. BJR
    Joined: Mar 11, 2005
    Posts: 6,652

    BJR
    Member

    X2 the rod between either the pedal and booster is too long or the rod between the booster and master is too long.
     
    gimpyshotrods and chryslerfan55 like this.
  4. 325w
    Joined: Feb 18, 2008
    Posts: 5,424

    325w
    ALLIANCE MEMBER

    X3
    Does it have a pedal return spring?
     

  5. mcmopar
    Joined: Nov 12, 2012
    Posts: 1,590

    mcmopar
    ALLIANCE MEMBER
    from Strum, wi

    Yes on return spring. Pedal is disconnected from booster. When cold no problem when there is heat that is when the
    Problem starts.

    I believe if it was a adjustment problem the rear would have the same problem and it does not.

    Sent from my SM-G930V using The H.A.M.B. mobile app
     
    chryslerfan55 likes this.
  6. I disagree. Sounds like the booster is putting slight pressure on master cylinder just blocking off ports in master. Unbolt master and see if it still does it. Sounds like you have plenty of clearance from exhaust. The brake lines should be able to heat up. The increase in pressure should be released inside the master if there is no input pressure.


    Sent from my iPhone using H.A.M.B.
     
    metlmunchr likes this.
  7. mcmopar
    Joined: Nov 12, 2012
    Posts: 1,590

    mcmopar
    ALLIANCE MEMBER
    from Strum, wi

    Winner winner, just loosened the master and no problem. I have been adjusting rod between the pedal and booster. I asume there is adjustment on the rod from booster to master. I will know in a few minutes.

    Sent from my SM-G930V using The H.A.M.B. mobile app
     
  8. 29moonshine
    Joined: Dec 30, 2006
    Posts: 1,303

    29moonshine
    Member

    disconnect the hose to the booster . i got a bad booster from speed way . it was building pressure while driving and applying the front brakes
     
  9. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,684

    V8 Bob
    ALLIANCE MEMBER

    The clearance between the booster and master cylinder should be checked with full vacuum applied to the booster, or about 20" Hg. In my experience .040" was the target, but check your booster's requirement if possible.
    Make sure the pedal can move back farther than necessary to ensure full return of the booster input rod.
     
  10. Water in the brake fluid will do the same thing.. You may need to flush it out,...
     
  11. Sheep Dip
    Joined: Dec 29, 2010
    Posts: 1,572

    Sheep Dip
    Member
    from Central Ca

    I had the basic same problem on my 40 and finally figured out that the booster when it got hot from engine heat/fan that the diaphragm became more pliable if that makes any sense. Put a little extra clearance between the booster and master...…...problem solved.
     
  12. Ebbsspeed
    Joined: Nov 11, 2005
    Posts: 5,271

    Ebbsspeed
    ALLIANCE MEMBER

    My thought as well. If it only does it when the engine is running the valve in the booster may be bad, applying pressure to the pistons in the M/C.
     
  13. mcmopar
    Joined: Nov 12, 2012
    Posts: 1,590

    mcmopar
    ALLIANCE MEMBER
    from Strum, wi

    Thanks to everyone, I have been trying things all day and it was fixed in 9 minutes on the H.A.M.B. I will monitor it from here on out. I should be able to pick up 2 tenths in the quarter now that the brakes aren't sticking.
    Tony
     
  14. BJR
    Joined: Mar 11, 2005
    Posts: 6,652

    BJR
    Member

    Your welcome.
     
    gimpyshotrods and RICH B like this.

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