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Selecting a Master Cylinder Early Ford (for drummies)

Discussion in 'The Hokey Ass Message Board' started by backlash18, Aug 6, 2011.

  1. backlash18
    Joined: Jul 20, 2006
    Posts: 29

    backlash18
    Member

    I am researching the additional components to complete my braking system on my 29 roadster project. There will be drums full circle on the vehicle(buick fronts, 9" rear), but would like some help in understanding the how's and why's regarding the selection of a master cylinder. Several people have said to run a 1" bore; but I ask how, does one know the proper bore size to use? I have searched for this discussion, though I cannot find such a topic. Could someone identify different Drum/ Drum brake system requirements and the different styles of master cylinders used?
     
  2. Blacklisted
    Joined: May 19, 2011
    Posts: 82

    Blacklisted
    Member

    I would run whatever size the original MC bore was. I don't know if it is/was a 1" bore or not. Hopefully someone in the know will post up the size for you. Good luck.

    Al
     
  3. scrap metal 48
    Joined: Sep 6, 2009
    Posts: 6,075

    scrap metal 48
    Member

    I can tell you with 1940 Ford front brakes and a Ford or Chevy rear end, I have run a 1967 Mustang dual reservoir MC for "drum brakes" on a lot of my model A builds and it has been just find.. I can not tell you brake system requirements or different styles.....
     
  4. Here is a good thread
    http://www.jalopyjournal.com/forum/showthread.php?t=235235&highlight=brake+bible

    The Wagner or equivalent book breaks down brake systems for all makes and models. You are on the right track! Early Fords 39-48 used 1 1/16" bore MC's and 49-60 used 1".

    Wagner PN F73323 is Ford 67-72 Fullsize car manual 1" that works good with a 7/8" or 15/16" rear wheel cylinder. The Buick fronts were most likely 1 1/8" looking at my book also using a 1" bore MC.

    Hope this helps, I can look up exact year combos if needed. Trent
     

  5. backlash18
    Joined: Jul 20, 2006
    Posts: 29

    backlash18
    Member

    Thanks for all of the replies. It will take me some time to review this information and consider a new question. Be back soon!
     
  6. mt shasta steve
    Joined: Mar 26, 2010
    Posts: 270

    mt shasta steve
    Member

    I have 1" bore on both my cars. Ford style on the coupe and Cheby style on the little truck. If you go 1" you can some day switch to front disc and use the same M/C. Or go power in the future and still use it. A 1 1/8" bore does not work well with manual brakes. IMHO a 1" M/C gives you more versitility down the line. I put residual pressure valves on my drum setup, even with the M/C on the firewall.
     
  7. backlash18
    Joined: Jul 20, 2006
    Posts: 29

    backlash18
    Member

    Alright. Now might be a good time to give some specifics on the equipment that I have gathered. My 9" came from a '72 Turino. Up front, I am doing the Buick drum swap so early model Ford stoppage there. "Tman"- thanks for the link. It seems that "Drivem" has the right terms that I want to learn more about. For example; choosing bore size, pedal leverage ratio, proportioning valve (I have read that proportioning valve is made internally in some Drum brake M/C's). Is there a formula for putting all of this together and a "ideal" brake system pressure that can be achieved? Lastly, not trying to be ugly, but I have started the project with a frame. Nothing ever existed on this thing before. I figured that the only way to learn was to jump in blindfolded at night!
     
  8. JohnEvans
    Joined: Apr 13, 2008
    Posts: 4,883

    JohnEvans
    Member
    from Phoenix AZ

    4 wheel drumbrakes do not use/need a proportioning vavle except in some VERY special cases. IE very large brakes in the rear of a very light car. Never heard or seen a prop. valve built into a MC. 5-6 to 1 pedal ratio is a basic setting for manual brakes. You usually will be in the ballpark with a 1"or 1&1/16 " bore master on normal American car drum brake systems either single or dual.
     
  9. Good post. I have a question. Is there a preference for firewall mounted or under floor mounting. Is one better than an other or??
     
  10. Whatever fits best!
     
  11. swissmike
    Joined: Oct 22, 2003
    Posts: 1,297

    swissmike
    Member

    If MC is mounted low, you may need residual pressure valves to keep the fluid from running back into the MC.
     
  12. tomcat11
    Joined: Mar 31, 2010
    Posts: 130

    tomcat11
    Member
    from Kalifornia

  13. mastergun1980
    Joined: Oct 18, 2010
    Posts: 1,095

    mastergun1980
    Member
    from Alva OK

    That's the master cylinder I use to. Even used it with disc / drum combo (with a preportioning valve) and worked good to.
     
  14. JohnEvans
    Joined: Apr 13, 2008
    Posts: 4,883

    JohnEvans
    Member
    from Phoenix AZ

    You most likely will have excessive pedal travel with a 7/8 bore MC with that brake combo.
     
  15. tomcat11
    Joined: Mar 31, 2010
    Posts: 130

    tomcat11
    Member
    from Kalifornia

    I'm interested in your reasoning. I'm thinking it's because the 40 front wheel cylinders are 1-1/4" or 1-3/8" in dia. I did not realize they were that large until now. I'm now re-visiting the math myself. Thanks in advance.
     
    Last edited: Aug 9, 2011

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