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brake problems

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by coolhandluke, Jan 8, 2003.

  1. coolhandluke

    coolhandluke 1/2 ton status

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    last weekend I swapped axles to a 14bff and the heavy duty, 8 lug 10 bolt front. everything was fine (well, not really, but that's a different story) drove it for a couple days no problem, then my brakes start getting mushy and the brake light comes on.

    what's the light actually sense? I don't seem to be low on fluid, so what's the deal?
     
  2. txbluethunder

    txbluethunder 1/2 ton status

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    the proportioning valve senses an imbalance of pressure in the brake system. make sure your rear brakes are autoadjusting the drums...also make sure they're bled real well.
     
  3. Blue85

    Blue85 Troll Premium Member

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    The light means that the front and rear circuits have a lot different pressures. Either you have a leak or there is air somewhere. Air will make the pedal mushy. Also, if the shoes are too far from the drums, you will get extra pedal travel. You may be able to determine this by pulling on the parking brake and seeing where it engages.
     
  4. coolhandluke

    coolhandluke 1/2 ton status

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    parking brake, ha! that's a good one, we don't need no stinking parking brake!
     
  5. dyeager535

    dyeager535 1 ton status Premium Member

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    Thats what you think until the trannies park pawl lets go on a hill. It happens.
     
  6. R72K5

    R72K5 Banned

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    </font><blockquote><font class="small">In reply to:</font><hr />
    Thats what you think until the trannies park pawl lets go on a hill. It happens.

    [/ QUOTE ]

    yep! have had this happen many times in auto and manual trans vehicles, mainly trucks, the 79 k10 was the last truck i had park problem with, was th350 203 truck. never had the problem in a 465 or 420 trruck though, just three speed and th350 ones so far

    good luck
     
  7. zakk

    zakk 1/2 ton status

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    replace the mater cylinder. i did and it works great now. No idea why the M/C seems to fail after 1-ton swaps, but it does. I think it is the massive rear brakes
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    Bleeding the brakes alone can cause failure, so after an axle swap, that makes sense. Even if bleeding weren't necessary, if the pedal has any more travel than before with the new axle (different brakes) then the same thing could happen.
     
  9. imiceman44

    imiceman44 1 ton status

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    Yep like Dorian said, bleeding an old MC will most of the times destroy it's seals.
    They are so cheap that usually for time saving when I do major work in the brake system I change the MC without thought, the time saved will more than compensate, if I had to bleed the original, then it fails and I have to change it and bleed again, not to mention the hastle and the lost fluid.
    /forums/images/graemlins/thumb.gif
     

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