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Technical Master cylinder mount, firewall or floor, 41 Ford Coupe?

Discussion in 'The Hokey Ass Message Board' started by bushman, Oct 22, 2020.

  1. bushman
    Joined: Nov 17, 2008
    Posts: 24

    bushman
    Member

    I've seen master cylinders mounted on both floor and firewall on this site, but would prefer firewall on my 41 Ford coupe ... but some folks say floor mount is less prone to flex? Should I reinforce the firewall to solve flex if it is indeed an issue on these cars? Is 6" dual a good choice for either?
     
  2. phat rat
    Joined: Mar 18, 2001
    Posts: 4,392

    phat rat
    Member

    I have the master on the firewall with a good size piece of steel plate reinforcing the firewall. Sorry after 25 yrs I don't remember the thickness of it. If you do any junkyarding see if you can find an Astro Van for a booster. My experience with an 8" aftermarket dual diaphragm booster was for crap. I replaced it with the Astro Van booster in 03 and it's still on the car over 80K mi. later
     
  3. -Brent-
    Joined: Nov 20, 2006
    Posts: 5,734

    -Brent-
    Member

    I put a reinforcement piece on my firewall as well as some rods tying the pedal mount to my dash bar.
     
    scrap metal 48 likes this.
  4. phat rat
    Joined: Mar 18, 2001
    Posts: 4,392

    phat rat
    Member

    I forgot to mention a brace from firewall to dash. I used the pedal and it's mount/brace from a 60's GM The same mount is also for the steering column
     
    -Brent- likes this.

  5. bushman
    Joined: Nov 17, 2008
    Posts: 24

    bushman
    Member

    Thanks phat rat, I will hunt down an Astro master, still plentiful in pick and pull yards. Figured steel plate and brace will do the trick, those aftermarket master cylinders are pricey esp. if they don't work well! Love this site, a wealth of wisdom for the asking....
     
  6. scrap metal 48
    Joined: Sep 6, 2009
    Posts: 6,072

    scrap metal 48
    Member

    I started mounting them on the firewall awhile ago and I'll never go back to floor mount....
     
  7. rustydusty
    Joined: Apr 19, 2010
    Posts: 1,716

    rustydusty
    Member

    I used the swing pedal assembly from a '62 Studebaker Lark on my '50 Dodge. T 0519181041.jpg he bracket bolted through the fire wall, to the master cylinder, and also bolted to the dash. No flex...
     
  8. Tim
    Joined: Mar 2, 2001
    Posts: 11,577

    Tim
    Member
    from Raytown Mo

    Used a speedway hanging pedal to put mine on the firewall of the 46. Has a thick plate backer and a beefy bit of steel that ties to the column drop area of the dash. No issues with flexing.

    had a mustang dual master under the floor and it was nothing but a pain in the ass. I don’t see me ever putting brakes under the floor again
     
  9. goldmountain
    Joined: Jun 12, 2016
    Posts: 2,229

    goldmountain

    The advantage of the firewall mount is that it is easy to check fluid level and to top it up. Also easier to seal where the pedal goes through the floor. Unfortunately, it looks ugly out in the open like that.
     
    SlamIam likes this.
  10. goldmountain
    Joined: Jun 12, 2016
    Posts: 2,229

    goldmountain

    Forgot to mention that you can run a brake light switch that doesn't need to be waterproof and is reliable.
     
  11. Tim
    Joined: Mar 2, 2001
    Posts: 11,577

    Tim
    Member
    from Raytown Mo

    And you don’t have to deal with the added consideration of wheel cylinders above the master
     
  12. Dirk35
    Joined: Mar 8, 2001
    Posts: 2,032

    Dirk35
    Member

    They both have advantages and disadvantages:

    Under body frame mounted Pros:
    -If it was under the body mounted on the frame from the factory, its usually easier to go that route and use aftermarket products.
    -Usually under body mounted are for 20's-30's vehicles that have less room in the engine bay.
    -It makes the engine bay less cluttered looking.

    Under body frame mounted Cons:
    -More difficult to check/fill the M/C.
    -Have to consider residual valves.
    -Have to work around suspension (split wish bones), Exhaust, clutch, Transmission, and steering column for the brake pedal.
    -Brake light switches can be problematic to fit.
    -Have to seal firewall where pedal goes through, usually not sealed well (or at all).


    Firewall Mounted Pros:
    -Easier to fill/check M/C.
    -Easier to bleed brakes
    -Don't necessarily require residual valves, but might still require proportional valve depending on Disc/drum, or disc/disc and the M/C used.
    -Better options for Brake Light switch.
    -Firewall is sealed.

    Firewall Mounted Cons:
    -Can be considered ugly and can be difficult to keep Cast Iron M/Cs from rusting through the paint.
    -Might need to reinforce firewall, or make a pedal mount bracket that ties the M/C to the dash for support.
    -Takes up room under the dash.
    -Have to work pedal and steering column placement.
    -Firewall Mounted M/C can be difficult with engine placement (or will have to work around the valve cover) if changing to a large sized engine.

    My 1934 Ford Sedan has a under body frame mounted M/C, and I used the typical aftermarket kit. My 1929 Model A and 1949 Ford PU both firewall mounted M/C. On my 1949, I pulled the brake pedal and switch from a 1991 Ford Pickup, and made my own cradle type mount under the dash from 1/4" plate. For the Model A, I made a 1" square tubing structure for the dash when I cut out the stock gas tank, and made a bracket that bolts to the side of the brake pedal cradle thingy I made to mount it and stiffen it up.

    Model A (I made kinda a cradle that the brake pedal bolts to on the side):
    1928  Model A Steering column mount 5.JPG

    1949 Ford F1 (Made a brake pedal assembly that bolts to both the firewall and the dash):
    1949 Ford PU Brake Pedals 1.JPG
    1949 Ford PU Brake Pedals 2.JPG
     
  13. 1971BB427
    Joined: Mar 6, 2010
    Posts: 5,887

    1971BB427
    Member
    from Oregon

    I prefer firewall also, and made a 3/16" thick plate around 10" square behind the firewall to sandwich the master and brake pedal assembly. My pedal assembly is also braced to the dash, so there's zero flex in my firewall. I made up a cardboard template to attach the brake master, and pedal assembly. Then once it was bolted together I transferred it to my plate, and copied all the mounting holes. Bolted it in, and tack welded the corners so it could stay put if I ever unbolted the master and brake pedal.

    [​IMG]
     
  14. bushman
    Joined: Nov 17, 2008
    Posts: 24

    bushman
    Member

    Thanks all for your suggestions, glad I asked this question as most of us face this dilemma: floor or firewall? I like the firewall option, so thanks for the pros and cons, and the excellent pictures of different installations, this site is the best!
     
    -Brent- likes this.
  15. rustydusty
    Joined: Apr 19, 2010
    Posts: 1,716

    rustydusty
    Member

    Lot better chance of getting dirt into the system with a floor mount.
     
  16. gatz
    Joined: Jun 2, 2011
    Posts: 1,507

    gatz
    Member

    This is what I'm facing on the '40 Chrysler, too.
    My question is; "how far down from the top of the cowl should the MC be located?
    One helpful HAMBer (aw1950) took a measurement of 11" on his '51 Buick.
    OR, is it more important for the floor to the the pedal pad being a certain distance?

    @Tim , were you happy with the Speedway hanging pedal ?
    Somewhere I read that the ratio from the pedal pad to the pivot distance vs the plunger bolt to the pivot distance is 7:1.
    That sound about right ?

    thanks
    gatz
     
    Bandit Billy likes this.
  17. alphabet soup
    Joined: Jan 8, 2011
    Posts: 1,419

    alphabet soup
    ALLIANCE MEMBER

    I modified a '63 Dodge swing pedal assembly. Reverse mounted a Mustang master cylinder on it. All under the dash. Only thing the you see on the firewall is the heads of chrome carriage bolts. Works very good for me. Gene.
     
  18. Tim
    Joined: Mar 2, 2001
    Posts: 11,577

    Tim
    Member
    from Raytown Mo

    yup very happy with it. Very beefy, nice construction and paint/ powder coat. Easily adjustable and has provisions for a return spring
     
  19. Bandit Billy
    Joined: Sep 16, 2014
    Posts: 6,882

    Bandit Billy
    ALLIANCE MEMBER

    Depends on high (or low) you want that brake pedal pad. I had to locate my MC on the firewall in the 41 ford truck I am constructing. It took a bit of mock up to come up with a pedal that was low enough to be comfortable driving position while having the MC high enough off the valve cover on the HEMI so you can remove the cover.
     
  20. scoop
    Joined: Jul 4, 2001
    Posts: 1,272

    scoop
    ALLIANCE MEMBER

    With a firewall mount master do you have have residual valves if the master don't have them?
     
  21. Tim
    Joined: Mar 2, 2001
    Posts: 11,577

    Tim
    Member
    from Raytown Mo

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