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1974 bay window 2 litre kombi - No brake pedal presuure

Discussion in 'Steering, brakes & Suspension' started by bobbyw, Mar 17, 2018.

  1. bobbyw

    bobbyw New Member

    Messages:
    20
    Location:
    penrith nsw
    all of a sudden after replacing new rear brake cylinders i now have hardly any brake pedal the brakes do work but only at the floor,all brakes have been bled, no air, the back brakes are adjusted up correctly, have checked master cylinder and all brake lines, dont have any leaks, used to have good brake pressure without engine running. I just read in ratwells that the kombi has to be level when bleeding , due to the proprtionaling valve setup . i will try that next, anybody got any ideas, would be appreciated
     
  2. oldman

    oldman Super Moderator Staff Member

    Messages:
    8,042
    Location:
    Avalon Beach NSW
    Really, can only be air in the system.... all nipples tightened ?
    Did you bleed the master cylinder ?
    I f no good when running, check that the vacuum line hasn’t dropped off the inlet manifold or the other end, at the brake booster.
    Booster needs complete vacuum line to work.
    Could also be a failed one way valve.....it’s inline with the vac. takeoff at the inlet manilfold end.
    Or a breech in the diaphragm within the booster itself.
    Start simple....check the vac. lines first.
    Good luck.
    Cheers,
    Mark
     
  3. bobbyw

    bobbyw New Member

    Messages:
    20
    Location:
    penrith nsw
    thanks mark
    but im talking about without the engine running so the booster is not relevent , do you think it could be the rear brake proportion valve, all other checked .
     
  4. oldman

    oldman Super Moderator Staff Member

    Messages:
    8,042
    Location:
    Avalon Beach NSW
    I’ve learned to never rule anything out...... however my mech. told me that these brake proportioning valves rarely play up.
    If they do, it’s usually ‘cause there’s crud inside.
    Agree, with engine off, you should still get “pedal”.
    I once tried one of those “ one person/automatic “ bleed kits that pressurise the line......bloody hopeless & couldn’t get pedal.
    One person behind the wheel that knows what to do ( pump n hold etc. ) and yourself at the wheel end of things cannot be beaten in my opinion.
    I’d go back n bleed em all again, it’s got to be something simple.....
    Cheers,
    Mark
     
    Wayne murray likes this.
  5. cbus

    cbus Well-Known Member

    Messages:
    10,921
    Location:
    sunshine coast
    Don't go to floor when manually bleeding.
    Can push a worn master past its usual spot and pick up crud or damage seal .
     
  6. Mordred

    Mordred Super Moderator Staff Member

    Messages:
    2,705
    Location:
    Penna, Hobart
    One thing I found the hard way, you need to bleed in a particular order. I think it is the front right then left then back right then left. basically the closest brake unit to the next closest and so on. Had lots of issues until I did that a few weeks back.

    Adrian
     
    David H likes this.

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