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vacuum leak? brakes/ac

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by bigdaddy89, Jul 5, 2001.

  1. bigdaddy89

    bigdaddy89 1/2 ton status

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    It has become hard to press the brake pedal down lately, and I am also having a hard time getting it to stop. I have listened to the master cylinder and can't here the seal leaking. I pulled the hose out of the power booster and it seemed to come out pretty easy. Does this need to be a snug fit? Any ideas to what the problem might be. My A/C won't blow very hard on high and the door on the passenger side under the dash is not opening. Do I need to change the vacuum dohicky behind the A/C controls to fix this. 1989 w/350, at.

    GOT ROCKS?
     
  2. jimmyjack

    jimmyjack 1/2 ton status

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    More than likely its your brake booster. Mines done that twice in the last 9 yrs. Brake pedal is hard to push down. No braking power. There's a diaphram inside the booster thats leaking. Sometimes you can hear hissing inside the cab that will go away when you depress the brake pedal.

    "My blazer may be slow, but it goes faster at higher speeds"
    <A target="_blank" HREF=http://community.webshots.com/user/blazerk5>http://community.webshots.com/user/blazerk5</A>
    Jim
     
  3. bigdaddy89

    bigdaddy89 1/2 ton status

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    I have listened for the hiss and can't seem to find any. I did hear a snake on trail 42 the other night, but that won't help me. Is there a nother way to check the booster?

    GOT ROCKS?
     
  4. DMK

    DMK 1/2 ton status

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    Put vaccum pump on booster, should hold vaccum.
     
  5. laketex

    laketex 3/4 ton status

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    hey bigdaddy, you still in the procomp shock business? I need a set next week bad!

    Sherman, Tx
    <font color=red>Come Awn yall...Let's go to LUCHENBACH, TEXAS!!!
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  6. WOODYJ

    WOODYJ 1/2 ton status

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    Yep, I agree with the other guys. Get another brake booster, heavy duty if you can find one cheap. That makes the brakes better and effortless. Don't forget the little Ralph Nader dohikkey either.

    k5woody I Don't Understand The Jeep Thing Either!!!
     
  7. bigdaddy89

    bigdaddy89 1/2 ton status

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    Jimmyjack, I went back out and listened again under the dash and heard the hiss, so you were right. Laketex, I no longer work for Offroad Unlimited. You can go onto there website at Macromotive.com and they will probably have some cheap. Or you can call them 1-800-947-7007.

    Does anybody agree with me on the vacuum thingymibobber behind the A/C controls to fix the door not opening and the high not blowing very well on the A/C? Thanks

    GOT ROCKS?
     
  8. dyeager535

    dyeager535 1 ton status Premium Member

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    One other test for leaks/failed booster is to start the truck....Let it run for a few seconds. Turn it off. During this process, don't touch the brake pedal. Let sit for about 45 minutes. You should STILL have vacuum assist left for at least two full brake applications with the truck still turned off. Of course, vacuum gauge would be quicker, but if you don't have one.

    Since you are having brake pedal problems (sounds like no or amost no assist) unless you can tell that the brakes are harder with the truck not running, this test probably wouldn't work.

    You may also check the one way valve that goes from the booster to the carb or intake. If the seal at the booster is bad, you would hear a hiss there when the truck was shut off, barring the internal diaphram hasn't failed : )

    One other test, not sure how credible it is...pump brakes with truck off, until no assist is felt. Apply pressure to pedal. Start truck. Pedal should move down easily now that you have assist.




    Dorian
    My tech/links page: <A target="_blank" HREF=http://www.dorianyeager.com/index2.html>http://www.dorianyeager.com/index2.html</A>
    No anti-theft measures on your truck? No pity when its stolen
     
  9. jimmyjack

    jimmyjack 1/2 ton status

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    Glad you figured out the brake booster. Kind of a scary feeling isn't it? My a/c is blowing pretty weak also. All four speeds, just not very strong. Someone told me my relay was bad. I'll check it out today and let you know what happens.

    "My blazer may be slow, but it goes faster at higher speeds"
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  10. bigdaddy89

    bigdaddy89 1/2 ton status

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    I replaced it. No more problems with the brakes. That is one thing I don't want to do again. Not much room behind that booster. Let me know about the relay. Thanks.

    GOT ROCKS?
     

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