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brakes issue ? need some help please ..

Discussion in 'General Chevy & GM Tech Questions' started by quicksilver8817, May 27, 2012.

  1. quicksilver8817

    quicksilver8817 New Member 100 Posts

    1990 k1500.. pedal hard at park and does not stop when put in drive .. pedal hard at low speed and does not want to stop but at cruising speed stops just about normal.
  2. 08_rado_rocker

    08_rado_rocker New Member 100 Posts

    Hmm.. could be a small vacuum leak it sounds like?

    Engine not creating enough vacuum to create the "boost" in the booster, but at higher engine speeds creating enough.

    I'm sure someone else will step in and give input as well.
  3. tbplus10

    tbplus10 Super Moderator Staff Member Platinum Contributor 1000 Posts 100 Posts

    Try putting the truck in park, revving up the engine, then trying the pedal.
    Does sound like you have a small vacuum leak.
  4. dpeter

    dpeter New Member 100 Posts

    Don't rule out bad vacume booster diaphram.
  5. 08_rado_rocker

    08_rado_rocker New Member 100 Posts

    :great: was gonna go there next if other didn't solve the problem.
  6. Josh

    Josh New Member 100 Posts

    sounds like my old mustang. had a bad booster leak. only stopped when up in the rpm range.
  7. quicksilver8817

    quicksilver8817 New Member 100 Posts

    well i just bought a master cylinder because its leaking anyway and the dont have the booster in stock .. anyway to che vacume on booster?
  8. dpeter

    dpeter New Member 100 Posts

    Get a hand held vacume pump and draw a vacume on the booster and see if it holds. Might be able to trace it to the booster by removing vacume line and plugging it to see if engine idle changes with it on and off.
  9. quicksilver8817

    quicksilver8817 New Member 100 Posts

    i pulled the vaccume line off .. engine is sucking .. i think its the booster because the problem persist with the vaccume line off leading me to believe the booster is not getting vacume ..

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