Trying to read this vaccum guage

Discussion in 'Troubleshooting & Diagnosis' started by valleyguy, Mar 4, 2020.

  1. COPO

    COPO Veteran Member Lifetime Gold Member

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    Huh, Unless you have a cam that only produces 8” or 10” then you can’t say it’s not healthy.
     
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  2. valleyguy

    valleyguy Veteran Member

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    My pedal is soft.... and I did the vacuum test and it was ok,. so looks like either a faulty part or air.
    With regard to the check valve, on the booster, can you elaborate? not sure how to "check" that.
    Also when I try to bleed the MC on the car, do I bleed from the MC ports or the proportioning valve? I saw a Utube video where a guy bled the MC by running a plastic, clear hose from the reservoir to the left front caliper and then repeatedly gently pumped the brakes to remove all the air.He swears that this method works.
     
  3. COPO

    COPO Veteran Member Lifetime Gold Member

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    Just bleed the MC 1st the normal way from the 2 bleeder screws.
     
  4. budro6968

    budro6968 Veteran Member

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    M/C's used to come with those little blue and yellow fittings with some clear tube to pump the juice back into the reservoir. I like to use the water bottle method too. That is B/C No one is ever around to help.
     
  5. CorkyE

    CorkyE Veteran Member Lifetime Gold Member

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    Do you have fluid coming out of the rear bleeders? If so, the proportioning valve is okay.

    Best is to bench bleed the master cylinder before install. If you bought a new master cylinder, it likely came with some plastic fittings, hoses, or some device with instructions included. Most common way is hoses attached to the two master cylinder ports, looped back into the reservoirs.

    I've never seen this but I can see where it might bleed the left front only, you would have to replicate on other three. There are much easier methods. I don't have a pressure bleeder, but I've tried the quick bleeder thingies, Mitivac pump, hose in bottle of fluid, etc. In my experience, ie; old age, nothing beats the two person method.
     
  6. Jodi

    Jodi Veteran Member

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    New calipers??? what kind... check bleeder screw, should be on top.
    Bleed the system again... start on the wheel farthest away from MC which is the Right Rear.
     
  7. Vettenick

    Vettenick Vettenick

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    To check the check valve on the booster.....run the car. Then turn it off. If you step on the pedal, you should get one or two "normal" pedal pumps, then the pedal should get harder. If you do get the one or two pumps, then your check valve is good.
     
  8. joeparamonkey

    joeparamonkey Member

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    Mine maintains at 16.5 at the rear booster port. Eddy 1406. Any thoughts?
     
  9. rocket dawg

    rocket dawg Veteran Member

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    Some people "tee'd" the PCV hose and the brake hose together which is a huge no-no. Make sure that isn't happening on yours and that your brakes are hooked up to full manifold vacuum or a port below the throttle plates on the carb. Usually there is a port behind the carb on the intake and it should run for the brakes and only the brakes.
     
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  10. mandis

    mandis New Member

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    Thanks a lot! I am good then because the gauge went to - 20 when I hooked it up with motor running. After reading from here, I get that is an adequate vacuum for my brake booster.
     

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