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vaccume leak ????

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by NoSmog73, Feb 3, 2002.

  1. NoSmog73

    NoSmog73 1/2 ton status

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    Ok here goes I put my foot on the brake and (out of gear) idle goes up (thought was check valve so I replaced no luck) but when cold come to stop in gear and It will idle way down to about 200 and then die if I dont get it into neutral. I will change the booster but anything or area that I can check (beside the usual vaccume lines on the carb maybe) thanks for any thoughts or tips again thanks later-mike
     
  2. dyeager535

    dyeager535 1 ton status Premium Member

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    don't throw the booster, they aren't hard to check. Start truck, don't touch the brake, let run for a few seconds. Turn truck off. Wait 45 minutes. Go back to truck, don't start it. Pump brakes. You should have 2 or 3 ASSISTED brake applies, before the pedal effort gets harder. A lot cheaper than replacing a booster that might be fine.

    Dorian
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  3. Grim-Reaper

    Grim-Reaper 3/4 ton status Author

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    A lot of times when a booster goes bad you can hear them sucking. Now they will make a noise when you first press the brake but once held they should be quiet. if you hear a sucking noise while holding it steady, it's bad. Then not holding vac is sualy the check valve but can also be a cracked diaphram. Do the test as descibed in the other post And listen for the sucking noise.

    Women dig dents and flat paint!
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  4. NoSmog73

    NoSmog73 1/2 ton status

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    thank you for the info will try this weekend??
     
  5. rain1971

    rain1971 Registered Member

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    I just bought 2 blazers, and on the one i decided to fix up, the brakes were terrible, i checked disc pads and they were very good still, so i thought, "master cylinder" so i changed it, no luck, then because i had the parts truck here anyways, i changed the vacuum booster, still no luck, now i know it is the calipers are sticky, wish i had read this post a month ago . :)

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