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Thread: Relocating brake master cylinder off firewall

  1. #1
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    Relocating brake master cylinder off firewall

    Need some ideas. I am swapping a 292 inline 6 into my '57 Chevy sedan. The car is a driver. Not a drag car and not a show car. Will occasionally tow a boat trailer.

    Here's the issue...... I am putting together a Weber intake and there are clearance issues on drivers side, so must relocate brake master cylinder.

    Split exhaust manifolds I am using drop right into the OEM mechanical clutch linkage, so I am retro-fitting a hydraulic clutch setup as well.

    I have never been into the custom car 'smooth firewall look' really. But as I must relocate the master cylinder and would like to add a power booster for the brakes in addition to retro-fitting a hydraulic clutch with booster as well...... How do y'all do this (master cylinder relocation off the firewall)? Do you weld brackets onto the frame rails and mount the master cylinder(s) under the toe board as on pre-'55 Chevys?

    Any ideas along these lines greatly appreciated.

    Best regards,

    Harry

  2. #2
    Registered Member chevynut's Avatar
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    I wanted the smooth firewall look on my Nomad so I moved my master cylinder outboard around 9-10" using a bellcrank similar to the stock Treadlevac. On the HEMI55 I had no choice but to relocate the master cylinder to clear the gigantic HEMI head. I ended up moving it over 6-7". It was easier to do on the HEMI55 since it has an automatic transmission and I didn't have to deal with a clutch. I made a hydraulic clutch setup for my Nomad that's inside the car.

    On both cars I used a steel plate to stiffen up the new firewall so things didn't move around too much under loads, and because the stock braces were removed. I designed both to have a pedal ratio of 4 to 1 since both cars use electric power brakes from ABS Power brake. It's the smallest setup available.

    There are other ways to do this.....some guys use a 90 degree brake bracket that sits under the dash. It takes up a lot of room. I never liked seeing the pedal go through the floorboard like an old truck, but some guys do it that way and it works. To me it looks weird, especially when the clutch pedal still hangs down from the brace. I've even seen the master cylinder and booster located in the trunk with a second master cylinder under the dash operating it.

    Here's an example of the 90 degree setup...there are several:






    Here's a Wilwood reverse swing setup for manual brakes...I don't know if it would fit under the dash.



    Here's what I did in my Nomad.

    20071111_999_19.JPG

    20071106_999_3.JPG

    20120210_0002.JPG



    Here's what I did with HEMI55

    20180405_007.JPG

    20180405_009.JPG

    20180129_007.JPG
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  3. #3
    Registered Member chevynut's Avatar
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    How far would you need to move the MC if you could move it outboard? Here's the stock PB setup:

    http://www.55-57chevys.com/tech/57/412-3.gif


    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  4. #4
    Registered Member NickP's Avatar
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    Nice response to an all too often issue

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    It would seem to be a big mess with the master cylinder under the dash if any brake work/fluid change is the future. Just does not seem to be a logical/practical location. The ford bronco years ago had a set up that redirected the booster and master cylinder off at about a 45 degree angle mounted on the firewall to provide room.

  6. #6
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    CN, do you think a hydroboost would save some space from the vacuum booster? I am doing a lot of research on hydrobrakes and the pump seems smaller.

  7. #7
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    Yes a hydroboost is smaller than most vacuum boosters for clearance to the engine. But it's obviously not smaller than just a master cylinder. You need a power steering pump to operate it.

  8. #8
    Registered Member NickP's Avatar
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    Quote Originally Posted by Gmvette View Post
    It would seem to be a big mess with the master cylinder under the dash if any brake work/fluid change is the future. Just does not seem to be a logical/practical location. The ford bronco years ago had a set up that redirected the booster and master cylinder off at about a 45 degree angle mounted on the firewall to provide room.
    With an external reservoir feeding the sealed master one lessens the issues of fluid.

  9. #9
    Registered Member chevynut's Avatar
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    Quote Originally Posted by scorpion1110 View Post
    CN, do you think a hydroboost would save some space from the vacuum booster?
    It depends on what "space" you're talking about. The Hydroboost is smaller in diameter than a vacuum booster and about the same length from the firewall, I'd say. I tried to use a Hydroboost for my Nomad and it was too long. As you can see it would have interfered with the tire in the relocated position. I had the same issue with the HEMI55 and ended up using the ABS Power Brake electric booster for both cars. Mine has a remote reservoir so the booster could fit it under the inner fender, and the reservoir has a sight window and a fluid level sensor since it's also hidden. The HEMI55 has an integral reservoir.

    https://www.hotrod.com/articles/1007...-brake-system/

    http://www.abspowerbrake.com/ehpm.html

    20090301_1253_modified.jpg

    With the hydroboost mounted so the accumulator is at the 2 o'clock position it frees up a lot of space for valve covers. Here's one on my Nomad in the stock MC location with the 502. The engine is raised a bit to get the harmonic damper over the steering rack, but it gives you an idea. A "standard" BBC installation will have a little more clearance.

    07290006.JPG

    07310023.JPG
    56 Nomad, Ramjet 502, Viper 6-speed T56, C4 Corvette front and rear suspension


    Other vehicles:

    56 Chevy 2-door BelAir sedan
    56 Chevy 210 4-door sedan
    57 Chevy 210 4-door sedan
    1962 327/340HP Corvette
    1961 Willys CJ3B Jeep
    2001 Porsche Boxster S
    2003 Chevy Silverado 2500 HD Duramax
    2019 GMC Sierra Denali Duramax

  10. #10
    Registered Member Custer55's Avatar
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    Another option would be floor mount pedals, Wilwood and others make these. Speedway would be a good place to look as they sell a bunch a race car stuff as well as street rod and muscle car parts. You can get the brake and clutch pedal combo that way too. Not sure how well they would clear everything but maybe worth taking a look to see.

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