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    Results 1 to 5 of 5
    1. #1
      Join Date
      Jun 2006
      Location
      Katy,TX
      Posts
      1,678

      Baffling brake problem

      Well this was originally my autocross car now switched to a drag car 79 Camaro/500" Pontiac motor.But you guys are good at brakes.



      Last outing this spring in the IA/Camaro ran 10.33@ 132.5 butsecond convertor was still to tight only 60 fting 1.54, so ordered one from Lenny at Ultimate. Car has sat since those runs because of COVID and 100 degree weather. Last weekend get in it to move it to the lift to swap convertors and brake pedal has a LOT of travel and is only making 800 psi at the floor front and back. But would hold that pressure not bleed down. Line Lock would hold pressure. Was making 1100 before . 1.03" Mopar MC . Hurst Line lock acting as my T for the front lines. SS flex line to Wilwood Dynalites 4 piston 1.75" on the front. Adjustable prop valve in the rear line. Rear is 79-81 TA brackets and rotors and 2.5""metric" caliper on it. Can't find a leak anywhere.

      This weekend it is down to 600 psi at the floor and by hand I could push the pedal 2" before any pressure is made. Took the lines off at the MC and plugged it and pedal barely can move 1/8" like a well bled MC. Still no leaks. RF wheel is pretty tight to turn by hand, a lot more than left. Rear seem to move OK but spinning rear end/trans would make it a little harder.

      Any thoughts? Stuck piston in the Wilwood?
      1978 Black Trans Am 455 Edelbrock heads [email protected] through mufflers on pump gas
      1981 Trans Am 400 stock type motor
      79 Camaro getting a 500" 695 hp IA2 Pontiac motor
      1965 GTO project car
      470ci/Chevy dual quad 409 604 HP 64 Impala SS project
      2004 Pulse Red GTO


    2. #2
      Join Date
      Apr 2001
      Location
      The City of Fountains
      Posts
      15,971
      Country Flag: United States
      Possibly an internal leak in the MC.

      Andrew
      1970 GTO Version 3.0
      1967 Cougar build
      GM High-Tech Performance feature
      My YouTube Channel Please Subscribe!
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      Dr. EFI
      I deliver what EFI promises.
      Remote Holley EFI tuning.
      Please get in touch if I can be of service.

      "You were the gun, your voice was the trigger, your bravery was the barrel, your eyes were the bullets." ~ Her

    3. #3
      Join Date
      Jun 2006
      Location
      Katy,TX
      Posts
      1,678
      Andrew that is what I was thinking at first until I plugged it and it had no excessive travel and hard pedal. I was about to pull it and swap on a a back up 0.94 " is why I plugged it.
      1978 Black Trans Am 455 Edelbrock heads [email protected] through mufflers on pump gas
      1981 Trans Am 400 stock type motor
      79 Camaro getting a 500" 695 hp IA2 Pontiac motor
      1965 GTO project car
      470ci/Chevy dual quad 409 604 HP 64 Impala SS project
      2004 Pulse Red GTO

    4. #4
      Join Date
      Jun 2006
      Location
      Katy,TX
      Posts
      1,678
      Update-the past two weekends bled the crap out of it since it I unhooked lines at MC. I could pump it up. Right front I could barely spin by hand left intermittently the same. I could pump it now and get 1000psi but then get crappy pedal. Pumped up then using line lok on front it kept a good pedal so seemed like that localized it to front. Plugged lines at the calipers.First one better, second one almost normal. Even releasing pressure did not free up the calipers on the rotor. So they are not releasing. I even had to use a pry bar to slide the right off the rotor and the left was easier but would not pull off easily. Pulling the pads off the outer pistons are 0.080 more out of the caliper on the right than the inner,and 0.060 on the left. Thinking we got some sticking pistons.
      1978 Black Trans Am 455 Edelbrock heads [email protected] through mufflers on pump gas
      1981 Trans Am 400 stock type motor
      79 Camaro getting a 500" 695 hp IA2 Pontiac motor
      1965 GTO project car
      470ci/Chevy dual quad 409 604 HP 64 Impala SS project
      2004 Pulse Red GTO

    5. #5
      Join Date
      Jun 2006
      Location
      Katy,TX
      Posts
      1,678
      Newer update-put two new Wilwood calipers on and have a nice linear pedal again and making 1000 psi . With just one caliper on easy to hit 1200. Rear GMs hit 800.

      Old calipers to get sent back to Wilwood for a look at and rebuild for back ups.
      1978 Black Trans Am 455 Edelbrock heads [email protected] through mufflers on pump gas
      1981 Trans Am 400 stock type motor
      79 Camaro getting a 500" 695 hp IA2 Pontiac motor
      1965 GTO project car
      470ci/Chevy dual quad 409 604 HP 64 Impala SS project
      2004 Pulse Red GTO





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