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brake problem

Discussion in 'Lifted & Offroad Suspension' started by Tarsis, Apr 20, 2009.

  1. Tarsis

    Tarsis New Member

    when my engine is turned off my brake is as solid as a rock but when i start my engine my brake goes all the way to the floor
    i have replaced my master cylinder, my brake booster, new wheel cylinders, blead all the lines
    can someone point me in the right direction to solve this problem
  2. mateospeed

    mateospeed Member

    Well, since it doesn't move with the truck off, it's not a leak, or an air bubble. Your ABS system or poportioning valves could be bypassing all the time, causing a re-circulation in the brake system.

    When the pedal goes to the floor, do you get any stopping power at all? Or is it just weak? Estimate for me in percentage of previously available stopping power.

    -Matt
  3. Tarsis

    Tarsis New Member

    ok i do have some stopping power not a lot its about 25% of what i use to have it dos not stop like it is supose to
  4. retired

    retired Rockstar 100 Posts

    Pull the wires off of the abs unit and give it a try. Those ABS units go bad, but you can drive it with the wires disconnected. I drove my 92 blaser for years like that.
  5. tommyboy

    tommyboy Member

    I had a similar problem and I know this might be a stupid response but are the rear shoes adjusted right, manual ones will have to be adjusted. If there automatic squirt a small amount of oil or lube on them and make sure there moving. The best way to adjust the automatic adjuster is to pump the brakes while backing up. Works on the automatic adjusters everytime.
  6. Tarsis

    Tarsis New Member

    i dont have abs it was not an option for my 1988 berbon
  7. willbradfan

    willbradfan Rockstar 100 Posts

    I had a similar problem like this with my suburban but it doesn't sound like you are leaking any fluid as I was leaking fluid but did not realize it. My suburban was leaking a bit of brake fluid within the rear drum brakes thus saturating the pads. I finally realized I was leaking by checking the master cylinder over time as mine has a separation wall to prevent the front and rear brakes from completely leaking all of the fluid out.
  8. mateospeed

    mateospeed Member

    Hmmm... Forgot about that. Try blocking off the front brakes (using line locks), then the rears, to see which end the problem is on.

    If it was a brake adjustment problem, it'd happen all the time; not just when the car was on.

    You have 4-wheel drums, correct?

    I would check your porportioning valve; it's most likely bypassing. I'll think about this some more.
    -Mateo

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