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  •  » Brake Pedal issue

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    6/06/2018 12:36 PM  #1

    cgomate
    FYI Addict

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    Registered: 4/01/2013
    Posts: 130

    Brake Pedal issue

    67 cpe 289 c4 daily driver

    Last summer I purchased the combined MC/booster kit... worked fine until last week.  I heard a hissing sound under the dash and assumed it was a vacuum leak related to the heater/ac system.  Turns out it is the brakes.

    After a year with no brake issues, I suddenly can't drive the car.  When I start it up, the vacuum to the booster will actually cause the brake pedal to go half way to the floor, and won't come back up.  It returns to normal when I shut the engine off.  I've also lost a good amount of the brake fluid in the MC.

    What am I dealing with here?

     

     

    6/06/2018 1:26 PM  #2

    Alessandro
    I FYI 24-7

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    From: Modena -Italy
    Registered: 7/08/2016
    Posts: 707

    Re: Brake Pedal issue

    hi , i will follow the brake line or mc fittings and check for leaks  everywhere as first .   
    The car should brake good , only with much force on pedal ,  if booster not work.
    The booster may have diaphgram broken or load spring broken and mc could have some o rings broken or simply old and dont keep pressure.
    If your leaks are from mc pushrod maybe you could not see it , like one drop in long time .
    hope it helps

     

    6/06/2018 1:26 PM  #3

    rpm
    Senior 24-7 FYI Addict

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    From: Bakersfield, Ca
    Registered: 9/17/2013
    Posts: 3,711

    Re: Brake Pedal issue

    Who's MC/booster kit did you buy? When my booster made a hissing sound it was leaking vacuum and needed replaced. I'd figure your brake fluid is leaking into the booster since you don't mention seeing any obvious leaks at the wheels.

    Bob. 69 Mach 1, 393W, SMOD Toploader, Armstrong  steering, factory AC.
     

    6/06/2018 4:15 PM  #4

    TKOPerformance
    Hyper FYIFORD ADDICT

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    From: Newark, DE
    Registered: 12/15/2014
    Posts: 7,621

    Re: Brake Pedal issue

    rpm wrote:

    Who's MC/booster kit did you buy? When my booster made a hissing sound it was leaking vacuum and needed replaced. I'd figure your brake fluid is leaking into the booster since you don't mention seeing any obvious leaks at the wheels.

    BINGO!

     

    6/06/2018 6:28 PM  #5

    cgomate
    FYI Addict

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    Registered: 4/01/2013
    Posts: 130

    Re: Brake Pedal issue

    67-70 Bendix booster & PB-6.1 Iron master cylinder... from a reputable source.  

    I'm more curious about the symptoms.  Has anyone else had the pedal behave like this before?





     

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