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brake problem????????

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by fulltopblazer, Apr 4, 2002.

  1. fulltopblazer

    fulltopblazer 1/2 ton status

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    I just installed disk brakes on the rear of my blazer (14 bolt ff) I have bleed them several times and still have a soft pedal. When you really slam on the brakes and it goes all the way to the floor the brake light comes on. I have a new master cylinder on it new d44 calipers new brake hoses new rotors everything. When your pumping the brakes up to bleed them they get stiff and feel like you have good brakes but when you start it up and drive it not much their I mean it stops but not as well as it did when I had drums on it.
     
  2. fulltopblazer

    fulltopblazer 1/2 ton status

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    Come on guys I need help I'm suppose to go to a mud bog this weekend and I can't stop this thing. I know thier has got to be something I'm overlooking here.
     
  3. zakk

    zakk 1/2 ton status

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    i have the same problem. I have been told it might be the master cyclinder is not up for the job. haven't attacked it since it hasn't been started in 3 weeks/forums/images/icons/crazy.gif
     
  4. arq

    arq 1/2 ton status

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    may want to try your brake pads, what brand are you using. i went through a similar ordeal with a 72 i had. took me about 3months to realize that the cheap brake pads i was using were crap. got myself some good ones and was able to lockem. BTW, it was a stock blazer, replaced ever single brake component durring that 3month period except for the brake pads.

    ARQ.
     
  5. fulltopblazer

    fulltopblazer 1/2 ton status

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    Its got new pads on it the best ones you can get from autozone. I was told that the stock master cylinder wasn't enough because the stock drums don't require as much presure. I was also told their was a residual valve in the rear brake system that needs to be removed but i've been unable to find out where it is at.
     
  6. BowtieBlazer

    BowtieBlazer 1/2 ton status

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    How new is the master cylinder? If you bled all the fluid through it could have damaged the master cylinder....Happened to me.....Also try pumping your brakesstiff while your truck isturned off. Start the truck and the pedal should go limp....thats how I check my power booster.
     
  7. BigBadCad

    BigBadCad 1/2 ton status

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    I just finished a disc conversion on my 14bff a couple of weeks ago and the master cylinder applied enough pressure to the rear disc brakes without changing a thing. I even checked it on a diagnostic skid pad that showed the braking force applied at each wheel. I think that you might have damaged the master cylinder while bleeding the system.
     
  8. fulltopblazer

    fulltopblazer 1/2 ton status

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    The master cylinder is about 6 months old I replaced it before I did the disc brake conversion and drove it with the drum brakes and everything worked fine. But i've been wandering the same thing I'm going to dig up the reciept and return it I think it was life time gaurented. With the truck turned off the pedal is stiff then when you turn it on it sinks I think the booster is fine.
     
  9. K10ANDYKHAMNIC

    K10ANDYKHAMNIC 1/2 ton status

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    read your chiltons manual . on the proportioning valve there is a " button " thats sposed to be held down while bleeding .
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    I don't think Chiltons is right. I think thats a "fall back" device to help "re-center" the proportioning valve in case it doesn't by itself. The GM manual mentions something about the brake pressure SHOULD be enough to re-center the valve, but if not, the button is there. If it's not centered, the brake light would always be on.

    Looking at http://www.dorianyeager.com/combovalve.html it appears that button would do nothing unless the valve was off center. In the center of the prop valve top, in the top picture, you can see the warning light "switch"....if the valve moves either way, it will trigger the lamp. If the valve moves to the left, and didn't re-center itself, it looks like that "button" on the left side can be used to force the valve back on center. Probably why some have reported difficulty pressing it in.
     
  11. 6.2L Jimmy

    6.2L Jimmy 1/2 ton status

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    Hey All,

    I know for a fact that the proportioning valve for a disc/drum brake system and a disc/disc brake system are different . Check it out. Hope this helps.

    Mike
     

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