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Power brake vacuumm on an 88 K5..........

Discussion in 'The Garage' started by dirtwarrior17, Feb 20, 2005.

  1. dirtwarrior17

    dirtwarrior17 Banned

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    I have a holley tbi with an extra vacuum for the pcv valve and I need a spot that generates enough vacuum to run my power brakes off of. I'm not running a pcv valve anymore because of the breather on the new motor's valve covers and i don't want to. The pcv vacuum off the tbi is pretty big as far as vacuum lines go but not as big as the stock vacuum spot which comes off the A.I.R. system for the brakes. I can't hook it up to the stock vacuum (because i nolonger have an A.I.R. system, dumped it when i put headers on) so i need to know if the pcv port on the holley tbi will generate enough vacuum to run the brakes.
     
  2. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    just plumb it into the manifold, should have a spot. i can't remember if the PVC is ported or not, i don't think it is. it should be big enough
     
  3. diesel4me

    diesel4me 1 ton status Premium Member

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    use a seperate port if possible...

    There should be a place on the manifold to get vacuum from that is plugged off with a pipe plug--if not,and the PVC hose is your last resort,make sure you put the charcoal canister dewhickey(looks like an inline gas filter) in the hose to the booster,it helps keep the oil fumes from rotting the rubber diaphram in the brake booster out--its best to keep the booster on its own vacuum line if possible..:crazy:
     
  4. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    actually its a check valve, so when the engine stalls, there is still vacuum in the booster to let you stop.
     
  5. diesel4me

    diesel4me 1 ton status Premium Member

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    nope,not that thing!

    No, I mean the black thing inline BEFORE the check valve!!--it looks like an inline gas filter,it has charcoal granules in it to help absorb fuel and oil vapors and keep them away from the diaphram in the booster..the check valve is the white or clear plastic dewhickey that plugs into the rubber grommet on the booster...not every GM vehicle has the charcoal canister thing,they started using them in the late 70's--whether or not it really does help much is debatable I guess,since older cars had none--but GM must have thought it helped,or they wouldn't have put them on...:crazy:
     
  6. big83chevy4x4

    big83chevy4x4 3/4 ton status

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    i always thought that was the check valve and the white thing was just a fitting. ill have to pull one off and look at it :thinking:
     
  7. dirtwarrior17

    dirtwarrior17 Banned

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    How big is it? I have a canister but, does it go to the tbi or the booster? It sits on the driver side up front by the radiator and is about 8 inches tall. I'm pretty sure there was an "idle" vacuum canister on that year but i don't know for sure.
     
  8. diesel4me

    diesel4me 1 ton status Premium Member

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    nope!

    That canister near the radiator support with several hoses is for the emission control/vapor recovery for the fuel tank--its about the size of a coffe can--that has nothing to do with the brake booster.....

    The one I'm speaking of is in the vacuum hose that goes to the power brake booster,its about 1-1/2 inches in diameter,and three inches long...one end has a 90 degree elbow,the other end is straight...damm,I wish I knew how to "cut and paste" a picture !!...If you look in the "lets see your motor" post pictures,you'll probably see it in one of the pictures....:crazy:
     
  9. dirtwarrior17

    dirtwarrior17 Banned

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    I'm in the same boat man.... registered user not member. I think i know what you are talking about. doesn't have a 90 degree elbow but its the size your talking about.
     

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