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Brakes - Power boosters

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Emmettology 101, Jan 26, 2001.

  1. Emmettology 101

    Emmettology 101 3/4 ton status

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    I am having an air leak problem somewhere around my brake booster/master cyl. I am hoping thatit is just the grommt that goes into the booster and the line going to the manifold that is the problem.
    If it is the Booster with the probelm, should I just get a normal stock one, or would it benefit me any to go with a 1 ton Booster? I am planning on going to rear discs someday....

    Thanks..

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; <A target="_blank" HREF=http://emmett.coloradok5.com>http://emmett.coloradok5.com</A>
     
  2. You can use a small propane bottle to check for leaks.Sounds like it could be inside the booster though.A friend switched to the bigger booster,he said that he liked it beter than the 1/2 ton part.
     
  3. Emmettology 101

    Emmettology 101 3/4 ton status

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    Do you know if he only changed the booster or do you have to get a 1 ton Master cylinder also?

    I am going to try and change the grommet, connectors, and hoe. If that dont work I will need to get a new booster..

    Wonder if I can use my 1/2 master Cyl with the 1 ton Booster? Probably would just be easier to change them al at once.

    Another thing I am going to try to make my brake a little better is to get an adjustable prop. valve and take off the stock unit.
    I talked to a guy on the Off-Road mailing list about htis and he said it works great.

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; <A target="_blank" HREF=http://emmett.coloradok5.com>http://emmett.coloradok5.com</A>
     
  4. Wheels

    Wheels 1/2 ton status

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    There's also a check valve in the line between the manifold and the booster that may be bad. You should be able to blow through it one way and not the other.
     
  5. Emmettology 101

    Emmettology 101 3/4 ton status

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    I eliminated the check valve a long time ago. I just have a stright line running to the connector that plugs into the rubber grommet into the booster.

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; <A target="_blank" HREF=http://emmett.coloradok5.com>http://emmett.coloradok5.com</A>
     
  6. Emmettology 101

    Emmettology 101 3/4 ton status

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    This leak is definatley brake related since Ihave to pump the brake about 3-4 times to get them to work and on the first pump you cna hear the air rushing out!

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; <A target="_blank" HREF=http://emmett.coloradok5.com>http://emmett.coloradok5.com</A>
     
  7. BlazerBoy

    BlazerBoy 1/2 ton status

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    Mine does the same thing, when i step on the brake you can hear air rushing out??? I have no idea what it is let me know what you do to resolve your problem....

    BlazerBoy
    http://generalblueballs.coloradok5.com
     
  8. Emmettology 101

    Emmettology 101 3/4 ton status

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    When the air rushes out of mine, the brake pedal goes to the floor until I pump it up...

    I will keep you posted on what I find.

    Mike [​IMG]
    See <font color=green>EMMETT</font color=green> -&gt; <A target="_blank" HREF=http://emmett.coloradok5.com>http://emmett.coloradok5.com</A>
     
  9. I think he still has the 1/2 ton master cylinder but I'll try and find out for you.The hole in the firewall where the break rod goes through and plunges into the booster is where it usaly leaks from,so you can here it inside very well.If they get to bad when you pump the breaks the rpm's will go up from the leak inside the unit.
     
  10. dyeager535

    dyeager535 1 ton status Premium Member

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    Don't have the service manual in front of me, but I believe a test for the master cylinder itself is to start the truck, do not use the brakes, turn it off, let it sit for 30 minutes to an hour, then attempt to use the brakes with the vehicle off, it should have enough vacuum for three applications.

    Dorian
    My K5 and Chev/Olds tech/links page: <A target="_blank" HREF=http://yeagerd.home.mindspring.com/index2.html>http://yeagerd.home.mindspring.com/index2.html</A>
     

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