Manual vs power brake master cylinder

Discussion in 'General Maverick/Comet' started by Popbumper, Sep 21, 2009.

  1. Popbumper

    Popbumper PINTO unashamed

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    Hi all:

    Is there any "real" difference between the manual and power brake master cylinders, in terms of outlets, reservoir sizes, etc.?

    I >do< realize the differences between the piston levers, the pedal hangar differences, and the booster setup, but what I am need to know is, can I put a manual master cylinder onto a power brake booster, and get the proper performance?

    I have a '76 Pinto I am adding power brakes to, but I am sure these setups are similar enough to the Maverick to warrant asking out here. Thanks for anything you can share.

    Chris
  2. Dave B

    Dave B I like Mavericks! Supporting Member

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    The bore might be different, are the part numbers for each different?
  3. Popbumper

    Popbumper PINTO unashamed

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    Thanks for helping me think more about this. I went back to RockAuto and looked at the manual vs. power - bore sizes are the same, BUT, outlet sizes ARE different, so I believe that answers my question. And yes, part numbers differ as well.

    Now, I am wondering whether the proportioning valve is also different between manual and power setups.

    THANKS, I love this site, you guys are always QUICK to answer!!!

    Chris
  4. Dave B

    Dave B I like Mavericks! Supporting Member

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    I have a 73 drum/drum master and a 74 disc/drum master (both new in the box) and I posted the visual difference between the two, on the tech articles, but I never measured the port sizes. Maybe someday I'll do that.
  5. Positively Ralf

    Positively Ralf Here and There

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    Since we are in the subject of brakes, what's the difference between power brakes and manual brakes?
  6. Dave B

    Dave B I like Mavericks! Supporting Member

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    One you have to push like hell (manual) and the other, takes less effort (power).
    There's more to up, but this isn't the place, Google will tell you, all you desire... :tiphat:
  7. Popbumper

    Popbumper PINTO unashamed

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    Wow, looking more at the factory master parts catalog and diagrams, they are the same master cylinder. HMmmm....

    Manual brakes use a simple lever (brake pedal) which pushes a piston into the master cylinder, compressing the fuid so that it cause the cylinders at the wheels to expand "outward" and make the shoes contact the drum or disc.

    Power brakes utilize an additional housing and diaphragm which is attached to the intake manifold of the motor. When the motor is running, it creates a negative pressure on one side of the diaphragm. When you press your foot against the pedal, you open the diaphragm to atmospheric pressure on the opposite side. This pressure of your foot added to the pressure differential (vacuum vs. atmosphere) on the diaphragm "adds up", and you don't have to press the pedal as hard as in the manual system to get an equal amount of fluid pressure through the brake lines.

    Hope that helped.

    Chris
  8. CaptainComet

    CaptainComet Well-Known Member Supporting Member

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    It is much more likely that you would have differences between a drum/drum vs a disc/drum MC than power vs non-power.

    Were early Pintos ever all drum? Didn't see that many back in the day even, but for some reason, the ones I have seen always seemed to be disc fronts.
  9. CornedBeef4.6L

    CornedBeef4.6L Voted off the Island

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    a properly set up manual brake set up is very close to a power brake pedal feel......factory manual brakes are not set up correctly...:cry:
  10. Popbumper

    Popbumper PINTO unashamed

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    Yes, early Pintos were all drum. Mine is a '76 and has discs in the front. After doing some more research I have come to the conclusion that the master cylinders ARE interchangeable. Thanks all for your replies.

    Automotive - it's an education.

    Chris

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