MC question

Discussion in 'The Bench' started by BuickGSrules, Oct 18, 2021.

  1. BuickGSrules

    BuickGSrules Gold Level Contributor

    Will a manual stock 1” dual MC that was used on drums be sufficient for running manual disc/drum setup? Thanks
     
  2. nekkidhillbilly

    nekkidhillbilly jeffreyrigged youtube channel owner

    i came here for late 80s rappers..............
     
    john.schaefer77 likes this.
  3. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I believe Disc brake master cylinders have a larger front section because the bigger piston requires more fluid in total. In addition, drum brake MCs have residual check valves for the drum brakes, something that would cause the calipers to drag.

    https://www.freeasestudyguides.com/residual-check-valve.html

    In addition, disc brakes require more pedal force to work.
     
    Lane in Mt.Hermon likes this.
  4. BuickGSrules

    BuickGSrules Gold Level Contributor

    Thanks Larry, I did not know that. Will my MC for disc power brakes then work manual or does that have another design?
     
  5. pbr400

    pbr400 68GS400

    I think you’ll need a master specifically for manual discs. Raybestos offers MC39204 and Dynamic Friction offers 35547036 for manual discs on Olds 442.
    (I looked up a ‘70 GS, a ‘72 GS, and a ‘72 442, to verify all three use the same MC for power discs; they do. I know the Olds was available with manual discs and it uses the two I listed first).
    Patrick
     
    Last edited: Oct 19, 2021
    BUQUICK likes this.
  6. LARRY70GS

    LARRY70GS a.k.a. "THE WIZARD" Staff Member

    I would say not. Different design I would think.
     
  7. BuickGSrules

    BuickGSrules Gold Level Contributor

  8. GMB-GS1

    GMB-GS1 Silver Level contributor

    Hi Jan,
    I just purchased an entire front disc brake conversion kit for Bruiser from Master Power Brakes. I am converting from 4 wheel power drum to manual drum/disc. They make the proper master cylinder for this conversion. Their website is mpbrakes.com
    Gary
     
    BuickGSrules likes this.
  9. BuickGSrules

    BuickGSrules Gold Level Contributor

    Thanks Gary.
     
  10. alvareracing

    alvareracing Platinum Level Contributor

    Late sixty's Corvette manual disc brake MC works good too. I use that one that has a 1 inch bore. I don't recommend any bigger bore because it makes it even harder to push the pedal. I used to run a 1.1/8 bore one and you had to eat your Wheaties before pressing the pedal. now with the 1" is easier. Been thinking going down one smaller size, would probably work better, more pressure than volume. m2 cents!

    Fernando
     
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  11. BuickGSrules

    BuickGSrules Gold Level Contributor

    Thanks Fernando
     
  12. Freakazoid

    Freakazoid Gold Level Contributor

    Which caliper is used with your rear disc conversion kit?
    Just curious.
    Mine uses the Cadillac rear integral park brake calipers. I think their
    Called. Very small piston compaired to front disc.
    But im using power brakes.
    They work great.
     
  13. Quick Buick

    Quick Buick Arlington Wa

    You can read this stuff till you blue in the face...
    Now lets just keep it simple..
    1 inch bore is for manual brakes.... disk drum,, drum drum,, disk disk....... if you use the 1 1/8 bore without the power booster you not going to stop when you need to.... You will need a HELLofa strong leg and very good floor boards to hold the seat in place...

    1 1/8 bore is for power brakes... end of story...
     
    BuickGSrules likes this.

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