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Spongy brakes

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by 78Jimmyish, Oct 27, 2001.

  1. 78Jimmyish

    78Jimmyish 1/2 ton status

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    When I put my front springs on, I had to disconnect the front brake lines, now my brakes are really spongy. What do I need to do to fix it?
     
  2. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    Bleed the ENTIRE brake system. Start at the farthest wheel and work to the closest. Be sure to get all the air out. Use lots of fluid. If that doesn’t fix it, bleed the master cylinder too. If that doesn’t do it, replace the master cylinder(AutoZone ~$30)! And if you do that, be sure to bench bleed it first!

    <font color=red>GOT MUD???</font color=red>
    My license plate reads:<font color=blue> 8 YR SUV</font color=blue>
    <a target="_blank" href=http://24.10.209.54/bigolk5.htm>http://24.10.209.54/bigolk5.htm</a>
    454/TH400/NP205 - 14BFF/D60/w/ 4.10s
     
  3. 78Jimmyish

    78Jimmyish 1/2 ton status

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    How do I bleed the system?
     
  4. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    You will need a buddy to help you. One of you has to sit in the truck. The person in the truck needs to pump the brakes 3 times, and then hold the pedal down. Once this is done, the guy at the wheel needs to open the bleeder at the appropriate wheel.
    Start at the rear passenger wheel cylinder. Pump, hold, and bleed. MAKE SURE TO CHECK THE RESIVOR FOR LOW FLUID, if the fluid levels go below the mark, you may have to start all over! Repeat 3 times, or until the air stops coming out of the lines. The go to the rear driver’s wheel, then front passenger, finally the front drivers. Once that is all done, you should have a better pedal. If not then bleed the Master. That one would require a manual, because I don’t remember the actual procedure for that process.

    You may also want to try a “power bleeder” from your parts store… I have heard a lot about them on this site, but never tried one.

    Hope that helps!

    <font color=red>GOT MUD???</font color=red>
    My license plate reads:<font color=blue> 8 YR SUV</font color=blue>
    <a target="_blank" href=http://24.10.209.54/bigolk5.htm>http://24.10.209.54/bigolk5.htm</a>
    454/TH400/NP205 - 14BFF/D60/w/ 4.10s
     
  5. wayne

    wayne 3/4 ton status

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    I tried it with somebody helping doing the pump and crack the bleeded but the were still very spongy. So my neighbor said gravity bleed them so I gave it a try. You can make your own kit like I did with a few containers that are cleen, I used the new ziplock plastic ones, and go to the parts store and have them pull a caliper for your truck and get some vaccum hose that fits the bleeder, get enough to go from the bleaders to the ground on all four wheels, I got 12 feet, crawl under the truck and cut the hose so it reaches from the bleader to the ground and cut a hole it the top of the container and put enough brake fluid in so the hose end is submerged, when all 4 are hooked up crack open the bleeders and take the top off the master cylinder and just keep adding fluid as it goes down. Do NOT let the master cylinder go dry or you will start all over again. After a few fills tighten the bleeders and top the master cylinder and put the top back on and check the brakes to make sure they are working good. If not continue to bleed the same way. Cost me about 12 bucks to do but it made a hell of a difference.

    See <a target="_blank" href=http://coloradok5.com/gallery/Waynes-Toy>Project Mighty Mouse</a> here.
    <font color=blue>Wayne<font color=blue>
    <font color=blue>Happy Trails<font color=blue>
     
  6. CaptCrunch

    CaptCrunch 1/2 ton status

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    Alot of times the prop valve get's stuck in one position and needs to be reset. One way to get it centered again is gravity bleeding the rears. The other alternative quite a few members have gone with is getting them power bleed at a local shop.

    -Mikey
    1987 Chevy K5 Blazer- 350 TBI
    <a target="_blank" href=http://coloradok5.com/gallery/captcrunch>http://coloradok5.com/gallery/captcrunch</a>
     
  7. Triaged

    Triaged 1/2 ton status

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    Just a few things to add:
    1) Wear a pair of saftey glasses (brake fluid in the eyes suks!)
    2) I think that using clear tubing is easer to bleed w/ because you can see the boubles of air better (I got some at Home Depot)

    '71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
    <a target="_blank" href=http://community.webshots.com/user/triaged>See it Here </a>
     
  8. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    They sell a min bleed kit at most parts stores. works great for $30
    can do it yourself with no help. When having somebody pump them you run the risk of them bottoming out the master and screwing it up. This way you don't

    Women dig dents and flat paint!
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    75 Jimmy, Dollar
    Grim-Reaper
     
  9. KRAZIE87K5

    KRAZIE87K5 1/2 ton status

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    Grim -

    Can you elaborate on that master bottoming out statement? Perhaps its time I go buy that $30 power bleeder kit! I would just like to know for my own knowledge... Thank you sir!

    <font color=red>GOT MUD???</font color=red>
    My license plate reads:<font color=blue> 8 YR SUV</font color=blue>
    <a target="_blank" href=http://24.10.209.54/bigolk5.htm>http://24.10.209.54/bigolk5.htm</a>
    454/TH400/NP205 - 14BFF/D60/w/ 4.10s
     
  10. Triaged

    Triaged 1/2 ton status

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    I have seen a few master cylinders go bad from this. The sealing surface of the master cylinder is often only clean in the area that it opperates in. When the peddle goes to the floor the corroded area of the MC will chew up the rubber seal. One way to minamize that is to put a piece of 2x4 under the pedal but the only way to eliminate it is to do vacume, pressure, or gravity bleading.

    '71 Blazer CST w/ a 400sbc, 4" lift, 36" Supper Swampers, and alot of rust
    <a target="_blank" href=http://community.webshots.com/user/triaged>See it Here </a>
     

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