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HELP!! Brakes stopped working!!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by KING K5, Mar 31, 2001.

  1. KING K5

    KING K5 1/2 ton status

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    All of a sudden my brakes aren't working!! I push on the pedal and it's totally spongy and makes some like "hissing" noise?!?!? I can barely stop!!! What is it? my brake booster? some brake vacuum line? I'm clueless so somebody please help me out!!! Thanks in advance
    Jeff
     
  2. muddin4fun

    muddin4fun 3/4 ton status

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    You prolly got a leak somewhere. Check all the hoses and bleeder screws (make sure they close) and then see if there is a leak in the master cylinder. It's getting air somewhere. Also, pull the back wheels off and see if you have brake fluid anywhere (like the wheel cylinder went bad).

    [​IMG]


    <A target="_blank" HREF=http://muddin4fun.coloradok5.com>http://muddin4fun.coloradok5.com</A>
     
  3. CaptCrunch

    CaptCrunch 1/2 ton status

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    Find the hiss... if the hiss is coming from under the hood you probably have a vac leak in the hose or else the booster itself is leaking.

    [​IMG]
    1987 Chevy K5 Blazer- 350 TBI
     
  4. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    OK Try 2! Got hyjacked by a bad JAVA script on when I screwed up trying to go to Dictionary.com DO NOT GO TO dictionay.com (missed the R). Script is screwed up and I had disconnect to stop it form opening browsers.
    ANYWAY back to your problem. Sounds like the Brake booster gave it up. Bet your idle jumps when you hit the brakes. The diaphram in the booster has probably cracked. The Hiss when you put you foot on the brakes is a suck not a hiss [​IMG] It is air bypassing the diaphram. A little sound as you apply the brakes is no biggie it the sucking noise once your on the brakes that's bad and the indication the booster gave it up.
    Not a horrible job to do and if your carefull you can unbolt the master from the booster and not disconnect the lines. JUST DON"T KINK THE HARD LINES. That would be very bad.

    Diging it in the dirt with my K5's
    Grim-Reaper
    <A target="_blank" HREF=http://grimsk5s.coloradok5.com/>http://grimsk5s.coloradok5.com/</A>
     
  5. KING K5

    KING K5 1/2 ton status

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    Thanks for the help guys, I think Grim is right and that it's probalby the booster. I'll get one tomorrow and throw it in!
    Thanks again!
    Jeff
     
  6. KING K5

    KING K5 1/2 ton status

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    Just wanted to let everyone know in case they have this problem in the future...it was the power brake booster that was bad. switched it out and my brakes work again!
    later!
    Jeff
     
  7. Sparky

    Sparky 1/2 ton status

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    Glad you found the problem, but this leaves me with a question. I figured if your brake booster went out it would cause your brakes to get really hard not spungey. I always diagnosed spungy brakes as haveing air in the brake lines. That has always been my experience. How does the leaky diaphram cause the breaks to get spungy? Educate me please! [​IMG] Thanks.

    Sparky

    When all else fails... Check the blinker fluid.
    78 K-5
     

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