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68 Mustang Master Cylinder port question?

Discussion in 'The Hokey Ass Message Board' started by Crazy Legs, Jan 5, 2013.

  1. Crazy Legs
    Joined: Sep 3, 2008
    Posts: 266

    Crazy Legs
    Member

    I'm getting ready to run the brake lines on my 54 Ford using a 68 Mustang MC and I forgot which port is the front and which is the rears.

    This MC is a disc/drum setup. The front port (furthest from the firewall mount) has a bigger thread ID than the other port if that helps & both resevoirs are the same size.

    Thanks for the help!
     
  2. the one farthest from the firewall should be for the front
     
  3. ABone312
    Joined: Aug 28, 2003
    Posts: 445

    ABone312
    Member

    The port to the front of the car is actually the rear brakes, the one closest to the firewall is for the front brakes. Usually on those master cylinders, the resevoir for the front brakes is a larger resevoir, but I have seen them even split on some aftermarket type cylinders. I work on alot of classic Mustangs, and use their masters on my Falcon and Comet projects.
     
  4. ok i stand corrected its been over a year since i looked at my 69's master
     

  5. Crazy Legs
    Joined: Sep 3, 2008
    Posts: 266

    Crazy Legs
    Member

    ok A bone, thats what I was thinking but figure I'd better make sure
     
  6. 57JoeFoMoPar
    Joined: Sep 14, 2004
    Posts: 5,286

    57JoeFoMoPar
    Member

    If it's the same as the 67 Mustang master, then the front reservoir is for the rear brakes. Figured that one out the hard way.
     
  7. 3 pedals
    Joined: Dec 29, 2012
    Posts: 52

    3 pedals
    Member
    from Ohio

    Does the one with the bigger thread ID use a larger line?
     
  8. gimpyshotrods
    Joined: May 20, 2009
    Posts: 19,951

    gimpyshotrods
    ALLIANCE MEMBER

    Not necessarily. It depends on the setup. You can get tube nuts in numerous sizes, for the same size line. I use 3/16" lines everywhere, with tube nuts appropriate for the desired thread size and pitch.
     
  9. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,819

    V8 Bob
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    I've never seen a '68-'73 Mustang disc/drum master that had same size reservoirs, so I'm betting yours is a drum/drum. However, even with a drum/drum master with reservoirs that look the same, the actual strokes or volume of the primary and secondary systems are not always the same, and the main reason the outlet ports are of different sizes, so the F/R lines can't be switched. (Front brakes always require more volume)
    If you do not know for sure how a master with equal looking reservoirs should be plumbed, do not use it! Find a disc/drum unit and always run the fronts to the larger reservoir, reguardless of the outlet port size. You will have to add an external 10 lb residual to the front stock drum brakes, and possibly one to the rears IF the stock rear internal residual behind the tube seat is not present. :)
     
    Last edited: Jan 6, 2013
  10. Crazy Legs
    Joined: Sep 3, 2008
    Posts: 266

    Crazy Legs
    Member

    Update: after more research I believe V8 Bob is correct, I've got a damn manual drum/drum Master cyl rather than the one I need...... That really blows since I just primed the firewall & ran the brake lines to my prop. valve.

    Correct me if I'm wrong but I show I need a 74-80 Mustang, Granada, or Maverick M/C??? They have it for a manual disc/drum and they do have different sized resevoirs. I show Cardone #10-1614 or A1131614 or Brake best #NMC1614

    I'm going to try to exchange my 68 drum/drum & get the right one tonight but I think I'm screwed cuz I sanded off all the sharp parting lines & rough casting even though its never had fluid in it.
     
  11. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,819

    V8 Bob
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    The common '68-'72 Mustang disc/drum will have the same 1" bore, as with most other '60s-'80s FoMoCo masters. The '74-up M2 has a smaller 15/16" bore.
     
  12. Crazy Legs
    Joined: Sep 3, 2008
    Posts: 266

    Crazy Legs
    Member

    Ok sounds good, but I can't find any disc/drum m/c's that aren't for power brakes?
    The only one I can find is the m/c's listed above.

    This I'm sure is a newbe question but will 1/16" make any difference in bore size?

    Thanks for the help guys!
     
  13. lowsquire
    Joined: Feb 21, 2002
    Posts: 2,564

    lowsquire
    Member
    from Austin, TX

    Disc brakes need a power booster, and all oem disc braked cars run one.
    Thats why you cant find one for non boosted brakes.
    1/16 " will make a difference to pedal travel and output pressure, you really need to have a good knowledge of brake system hydraulic theory if you deviate from a stock master/wheel cylinder ratio.
    I think your best bet is to use the master that is applicable to the front discs you are using, and then match the rear wheel cyl. size to that same original car size. forget the prop valve, if you set it up as per the oem car you take the components from ,you wont need it. and run a booster. sorry its going to mess up your firewall paint..but its a bigger problem to stop your car safely.
     
  14. Not all disc brake oem cars ran power boosters. My 72 Vette is disc braked and does not have power booster and has never needed one. I also have seen a Granada with front disc brakes that had no power assist from the factory.
     
  15. V8 Bob
    Joined: Feb 6, 2007
    Posts: 2,819

    V8 Bob
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    Power assist was an option on many small and mid sized disc braked cars for several years.



    A power assist master is a good choice in custom applications because of the deeper push rod counter bore that many have, and is important when using a non-retained push rod.

    Curious what are the brakes on your '54, stock or upgraded?
     
  16. tommy
    Joined: Mar 3, 2001
    Posts: 14,757

    tommy
    Member Emeritus

    I'm afraid your blanket statement is incorrect. (in the U.S. anyway I know nothing about down under) I bought a damaged 71 Camaro for the drive train. It came stock with a non-power disc brake system. I used all of the brake components on my 34 Ford P/U. Everything! M/cyl., dist block, calipers, rear end etc. Only the brake lines were made by me due to the different locations. Pedal under the floor with a P&J pedal (no special valves for under the floor application)
    [​IMG]
    My first 34 P/U I drove it to Timonium for the 50th anniversary in 1984.
     
    Last edited: Jan 8, 2013
  17. Crazy Legs
    Joined: Sep 3, 2008
    Posts: 266

    Crazy Legs
    Member

    the 54 had 4 wheel drums & the Tredalvac powered mastercylinder, its all gone now and has S10 disc's up front & 11" drums in back from a 57 9" Ford rear.

    The stock brake pedal assy had a bunch of linkage under the dash for the Tredalvac setup, I since have removed this and using the stock pedal for the push rod mount. Its 2" below the pivot point and I figure that gives it a 6:1 ratio (this hole hasn't been drilled yet so this can change if needed)

    Last night I ordered a 74 Maverick m/c thats a "non-powered" disc/drum setup it'll have a 15/16" bore.

    What you think? Its surely better than running the 68 mustang drum/drum m/c on my disc/drum car right even though its a 1" bore?

    What about getting the 68 mustang disc/drum m/c thats for power brakes for my non-power brake car?
     
  18. zibo
    Joined: Mar 17, 2002
    Posts: 2,351

    zibo
    Member
    from dago ca

    I think that maverick one will work.
    Hope so anyway I just ordered one yesterday too!
    Same thing disc (speedway kit) front with 9" rear.
    I cheesed out and got the cheap one though.

    Years ago I did the same for a 53 suburban,
    and the brakes were great with manual disc fronts.

    TP
     
  19. bluestang67
    Joined: Feb 7, 2007
    Posts: 589

    bluestang67
    Member

    This is a standard drum - drum from a 67 Mustang the same for 68
     

    Attached Files:

  20. Thunderroad312
    Joined: Nov 18, 2012
    Posts: 158

    Thunderroad312
    Member

    Front disc brakes do not require a booster.The Ford intermediates and compacts in the early seventies were available non power. The Master cylinder for a '73 Mustange dic/ drum works perfectly.I have done the conversion you are doing many times and the car will stop just fine without the bosster because it is not that heavy. The master cylinder doesn't know weather there is a booster or not. Make sure you get the pushrod length correct so you have a full stroke.The pushrod usually needs to be made longer. And yes the rear port serves the front brakes on 99.9 percent of all dual master vehicles.
     
  21. Crazy Legs
    Joined: Sep 3, 2008
    Posts: 266

    Crazy Legs
    Member

    bluestang, that is the I had, I don't know why in the world I didn't question the same size resevoirs when I got it. oh well live and learn :)

    Yes I agree on the pushrod length, I'll post back what I find out tonight when I can compare the new disc/drum m/c.
     
  22. Crazy Legs
    Joined: Sep 3, 2008
    Posts: 266

    Crazy Legs
    Member

    Ok, heres the latest, I got the Brake best #NMC1614, it is the same bolt pattern as the 68 mustang, the main difference is the rod length and the overall size of the resevoirs, much taller and the rod is longer but the stroke seems to be the same.

    The fittings that you'll need from the m/c to the brake lines are also different.

    TBD if it'll make the car stop lol but already it makes me feel better that I have the correct one for my application. Thanks guys for your help!
     
  23. Nonsense - there are MANY applications of cars with Disc front and Drum rear with non power brakes.
    As stated the Maverick is a very common choice for this - I have used many of them in Hot Rod builds. In fact it's running joke at my local NAPA store - "Are you doing brakes on yet another Maverick?" whenever I go on there.

    To the CRAZYLEGS, if they don't want to take that one back and you want to make me a good deal on it to recoup some of your money - PM me.
     

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