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Brakes need fixing before the 19th!!

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Gold Rush, May 13, 2001.

  1. Gold Rush

    Gold Rush 1/2 ton status

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    Well I'm having lots of trouble with Gold Rush this week. Front brakes have pressure going to them all the time. A couple of weeks ago the left front caliper was locked up. I changed both front calipers, front pads and turned the rotors. Now when I was changing tires this week I noticed my hubs were hotter than hell. The front wheels didn't want to turn by hand either. I cracked my bleeder screw on each caliper and it freed up. O.K. so that tells me it's a master cylinder, right? Wrong, I changed the master cylinder and still does it. While bleeding the system (the rear screws open) the brake pedal only goes halfway down. Then when bleeding the front the pedal goes to the floor, but hardly any fluid comes out the bleeder. The only thing I can think of is maybe a proportioning valve, but after fifteen years of turning wrenches I've never changed a proportioning valve because it was internally bad. Look below for rig specs.

    Does anyone have any ideas?

    David 75K5
    <A target="_blank" HREF=http://www.extremeblazer.com>http://www.extremeblazer.com</A>

    Year: 1975
    Model: K5
    4X4
    front disc brakes
    Vacuum boosted power brakes
    Superlift extended SS brake hoses
    New (rebuilt) calipers last week
    New master cylinder this weekend

    Help I don't have much hair left and I'm pulling it out!!!!


    [​IMG]
     
  2. gokartergo

    gokartergo 3/4 ton status Staff Member Moderator

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    I have no idea but I'm putting it back to the top for you......Dan
     
  3. FRIZZLEFRY

    FRIZZLEFRY 1/2 ton status

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    Theres a ckeck valve in the proportioning valve that could be causing this.Ive never seen it happen but if it stuck I think it could cause your problem.Good luck.

    Proving once again that man CAN live on beer alone
     
  4. dyeager535

    dyeager535 1 ton status Premium Member

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    I know for sure on the later GM cars/trucks, and I assume yours as well, if everything is operating correctly, when you bleed your brakes, with the key "on" the brake light should come on. If it doesn't, ground the wire going to it, and if the brake light comes on, the proportioning valve is bad.

    Not sure how the proportioning valve could cause pressure to "say" at the front wheels, but if I understand the valve correctly, fluid goes into the PV from the MC, and out to the wheels. Guess somewhere something could be acting as a one way valve...PV is pretty simple though....picture on my page http://www.dorianyeager.com/index2.html
    No anti-theft measures on your truck? No pity when its stolen
     
  5. Burt4x4

    Burt4x4 3/4 ton status

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    Ya know I had a similar issue but it was only one side. My calipar locked or didn't relase all the way and it smoked my brake pad and turned my rotor blue. I bought a new calipar thinking that would fix it. I used one of thoes hand vac pumps to bleed my brakes and low and behold a huge chunk of crap came out of that same sides brake line. So I think it was alowing fluid to pass by the crap but then when the pedal pressue was released the crap help the line pressuer at the caliper...just a guess but flush your lines as best as possiable.....

    Oh and I still don't have my rig back together so i'll have to take a rain check for FR trip this weekend[​IMG]

    72K5[​IMG]Led Zeppelin[​IMG]Rock ON![​IMG]
    <A target="_blank" HREF=http://www.burt4x4.coloradok5.com>http://www.burt4x4.coloradok5.com</A>
     

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