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Technical Relocating brake master cylinder off firewall

Discussion in 'The Hokey Ass Message Board' started by enigma57, Oct 26, 2019.

  1. enigma57
    Joined: Apr 12, 2007
    Posts: 246

    enigma57
    Member

    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. macdave06
    Joined: Dec 3, 2008
    Posts: 44

    macdave06
    Member

    How far over do you need to go? Danchuk makes a bracket to move the master over 2 inches and up close to the same.

    Sent from my LM-Q710(FGN) using Tapatalk
     
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  3. beater40
    Joined: Sep 19, 2006
    Posts: 86

    beater40
    Member

    These cars that had the treadle vac power brake option had the booster offset to the left which may be enough, for the clutch you could convert to cable using the original pedal also.
    Another option to go under floor maybe using the 55-59 pickup brake and clutch pedals and brackets, I haven't done this but no reason it couldn't be done.

    Sent from my VFD 710 using The H.A.M.B. mobile app
     
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  4. Mr48chev
    Joined: Dec 28, 2007
    Posts: 33,861

    Mr48chev
    ALLIANCE MEMBER

    Not a lot of clearance for a booster under those cars.
    As much as I don't like a master cylinder I'd be figuring out a way to offset it to the left. and that may not be that difficult with a non power unit but you would have to work out a cross shaft setup on the pedal.
    Without a booster you might be able to go with your original plan and adapt a pedal kit to put the master cylinder under the floor.
     
    Last edited: Oct 27, 2019
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  5. enigma57
    Joined: Apr 12, 2007
    Posts: 246

    enigma57
    Member

    Well, the Weber intake setup I have here requires a full 10" side clearance from where it bolts to cylinder head on drivers side (LHD). Sidedraught intake would not allow carbs + proper air cleaners (or fabricated air box) to be fitted. So I modified a sidedraught intake to fit 3 downdraught Weber DCNF carbs to this engine. Actually, it is now the outboard half of a 2 piece intake, as I must bolt 2 of these intakes together at what were originally their DCOE mounting flanges to make them work. Bonus is added runner length but they do require a full 10" side clearance to 'just' clear the OEM '57 Chevy brake master cylinder and its very tight there.

    With the 292 engine in the same position as the 235 its replacing...... I have less than 1/2" clearance between intake and OEM brake master cylinder if that much. And that is without room for throttle linkage and other items I need to fabricate (carbs on this type intake must be mounted with throttle shafts parallel to crankshaft on inline 6, so direction of throttle linkage pull must be redirected 90 degrees and then 180 degrees to position DCNF float bowls inboard and adjusting screws outboard and accessible...... And linkage to each carb must be individually adjustable as well, so linkage will likely be a Rube Goldberg looking affair when done). I might be able to shift the engine 1/4" or so towards the passenger side when fabbing engine mounts, but that would be about it.

    I would like to add a vacuum assist power brake booster similar to the '65 GTO unit you can see in my avatar ('56 Chevy with 400 Pontiac engine I built in the '70s)...... But there is just no clearance for the direct fit type. And the hydroboost units I have seen on trucks have their cylinder positioned on the engine side, so no clearance for that, either.

    All this is compounded by the fact that I want to retain a manual gear box in the '57 when I swap in the big 6. Unfortunately, my nearly 72 year old knees are shot...... And the split exhaust manifolding I will use with the 292 drops right into the OEM mechanical clutch linkage. So I will be retro-fitting a hydraulic master and slave cylinder from a Jeep to work the clutch. Will also be adding a remote servo assist I found on Aussie e-bay listings. Its a 7" diameter PBR VH44 having 5/8" diameter slave piston.

    I may have miscalculated when ordering this, as my clutch master and slave piston dia. are both 3/4". I see that there is a (much more expensive) VH44 remote unit listed which is 7.5" dia, and has a 3/4" slave piston diameter. Should I have got one of these to match up with my 3/4" Jeep clutch master and slave cylinder size? And are the remote slave units available separately from the vacuum assist units? Cannot seem to find listings for any.

    The other question is...... If I retain my OEM (non power assist) single reservoir brake master cylinder (I believe these have a 1-1/8" diameter piston)...... Would one of these remote servo assist units work if plumbed into the hydraulic line between master cylinder and brakes? Even if it has a smaller dia. slave piston dia.?

    Mac, I did look at the Danchuk offset mounting bracket you suggested. It is for a direct fit (firewall mount) power booster and even with a 2" offset, I could not fit one to my '57 with this particular intake setup. So that is why I am looking at remote mount servos (boosters) as an alternative.

    Thanks to all. Appreciate your thoughts on this,

    Harry
     
    Last edited: Oct 27, 2019
  6. wvenfield
    Joined: Nov 23, 2006
    Posts: 5,580

    wvenfield
    Member

    They make set ups that mount under the dash.
     
  7. enigma57
    Joined: Apr 12, 2007
    Posts: 246

    enigma57
    Member

    Thanks! I did find this just now......

    [​IMG]

    [​IMG]

    Might be able to do something like this and mount remote reservoirs to inner fender panel?

    Best regards,

    Harry

    P.S. >>> Not sure why image doesn't appear. If you do the reply with quote thing, you can see it even if you don't reply.
     
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  8. macdave06
    Joined: Dec 3, 2008
    Posts: 44

    macdave06
    Member

    As far as the clutch is concerned you could run a hydraulic throw out bearing and not have to worry about setting up brackets and linkage. Just needs a hose from the master to the throw out.

    The under dashs brake set up would be the way to go if it can't be mounted outside the firewall.

    Sent from my LM-Q710(FGN) using Tapatalk
     
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  9. alanp561
    Joined: Oct 1, 2017
    Posts: 4,611

    alanp561
    ALLIANCE MEMBER

    Check ECI for their offset 90 and 180 degree pedal set ups
     
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  10. enigma57
    Joined: Apr 12, 2007
    Posts: 246

    enigma57
    Member

    Thanks, Mac and Alan! The ECI offset mounts are very interesting. I may be able to make something similar. I will look further into the hydraulic throwout bearings. My youngest son has a master and internal slave cylinder setup that is OEM for '94 Camaro and he wants to pull the 700R4 out of his '92 3rd gen. Camaro and retro-fit the clutch pedal, hydraulic clutch setup and T-56 6-speed transmission from a 4th gen. Camaro into his car.

    I have looked at the OEM setup he has and have looked at a few aftermarket hydraulic throwout bearings as well. The ones I have seen so far have no adjustment to keep the throwout bearing from being in constant contact with the clutch fingers when the clutch pedal is not depressed and no easy way to bleed the hydraulics as an external mount slave cylinder would have.

    I will look at them again and see if there is one which has these features. Or perhaps I may find a way to add provisions for adjustment and bleeding the hydraulics. I'm in the habit of slipping a manual shift car into neutral at long stop lights to save the throwout bearing and clutch (and my left knee). The idea of having no way to manually adjust the air gap between throwout bearing and clutch fingers when the pedal is not depressed gives me the heebie -geebies.

    Best regards,

    Harry
     
  11. enigma57
    Joined: Apr 12, 2007
    Posts: 246

    enigma57
    Member

    :) Found some pics of mods to the 2-piece intake on another thread. This should give you an idea of how it is configured. You can click on the pics to enlarge them and get a better look......

    https://www.speed-talk.com/forum/viewtopic.php?f=1&t=52194&start=30

    Inboard half is unmodified......

    [​IMG]

    Outboard half is modified to fit DCNF downdraught carbs......

    [​IMG]

    Each half of intake spaces it 5" out from where it bolts up to the 292 head, so need 10" side clearance on drivers side (plus) to clear brake master cylinder.

    Best regards,

    Harry
     
    Last edited: Oct 30, 2019
  12. Mimilan
    Joined: Jun 13, 2019
    Posts: 1,230

    Mimilan
    Member

    What you're wanting was done OEM on RHD BMW E30's [They had a slant engine so the M/C booster needed to go on the LH side]
    BMW used 2 x 90 deg bell-cranks and a pull rod across the firewall [under the dash]

    BMW e30.jpg

    Here is a "stealth" under dash pedal kit [from Aussie]
    https://www.rrs-online.com.au/stealth-under-dash-brake-booster.html

    Or you can use a Wilwood pedal box with reverse mounted M/Cs [like competition cars use]
     
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  13. enigma57
    Joined: Apr 12, 2007
    Posts: 246

    enigma57
    Member

    Thanks, Mimi! Once again, you have opened my eyes to the possibilities. I really like what the BMW engineers came up with on the RHD E30! If I cannot work out something allowing for slight relocation of brake master cylinder with hanging pedals on drivers side of my LHD Chevy...... I could do the reverse...... A similar relocation of brake master cylinder and direct mount servo assist and move them to the right side of my firewall. Could always retro-fit one of the older style (early '50s) under dash heater units to make room under dash.

    The RSS under dash unit using a bellcrank for 90 degree directional change is quite interesting, as well.

    What I will do then is first...... To see if I can gain an additional 1/4 inch or so when finalizing front engine mount location. Yes, that's how tight it is. If I can do that, I will work out a way to do the hydraulic clutch conversion with remote servo assist and add a booster (servo assist) to the brakes as well. The Aussie VH44 remote vacuum assist servos you turned me on to should arrive in the next week or so and with a bit of finessing, I just may be able to gain the clearance to make it all work without unlimbering my 10 lb. hammer.

    Need to think about this. My mind is telling me all sorts of things at present...... Including the obvious...... Why not just change the car over to RHD and put the brake and clutch hydraulics on the other side of the engine bay..... No need to move steering box. Just build square tubing framework under dash and on right side, mount a short 6" or 8" axle shaft having needle roller bearings at each end. Mount steering wheel at top and dual sprockets at bottom of shaft with dual chains extending to matching sprockets on existing (shortened) steering shaft on other side of car (also supported by bearings and having matching chain sprockets affixed). Possibly add a 3rd axle shaft with dual sprockets near middle of car that will allow adjustment of chain tension. Then replace '57 US dashboard with '55 or '56 dash and move speedo and other instruments to right side similar to '57 RHD Chevys 'down under'?

    Or...... Why didn't I just begin with a 300 Ford inline 6...... Their intake and exhaust are on the opposite side (passenger side) of my LHD Chevy? Decisions...... Decisions......

    Many thanks for the ideas,

    Harry

    P.S. >>> Not to be rude...... I should have introduced my assistant...... This is Holmes......

    https://www.speed-talk.com/forum/download/file.php?id=14363&t=1

    We were adopted by our 2 youngest cats Holmes and Watson a few short weeks priour to the hand fitting of aluminum pieces forming my 2-piece intake. Both were young kittens when this photo was taken and both have since grown into fine 25 pounders. Great mousers they are. And inquisitive.
     
    Last edited: Oct 30, 2019
  14. goldmountain
    Joined: Jun 12, 2016
    Posts: 4,442

    goldmountain

    At one time, I had a late 80's Dodge Colt made by Mitsubishi that had the master cylinder and booster mounted on the passenger side with linkage behind the dash. Also remember early 70's Vauxhall Firenza that had a long pushed coming out of the firewall that worked a 180 degree bell crank and the master cylinder pointed backwards. Probably useless information.

    Sent from my SM-T350 using The H.A.M.B. mobile app
     
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  15. Ned Ludd
    Joined: May 15, 2009
    Posts: 5,026

    Ned Ludd
    Member

    My RHD 2002 had a different setup, manual MC on the right and two remote boosters on the left. It was my first thought when I saw this thread.
     
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  16. sunbeam
    Joined: Oct 22, 2010
    Posts: 6,214

    sunbeam
    Member

    I always hear put a SBC in it's easier how about run a 300 Ford painted orange and Chevy stickers the intake on the passenger side. But the slant and or offset the engine idea works for me.
     
    Last edited: Oct 30, 2019
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  17. enigma57
    Joined: Apr 12, 2007
    Posts: 246

    enigma57
    Member

    Thanks for sharing that information, goldmountain and Ned! Very useful, given the possibilities and I may very well end up doing all or part of what you describe.

    Interesting alternatives, sunbeam. Much appreciated. In addition to several small blocks and a big block Chevy, I have swapped several non-Chevy engines into these cars in years past. The engine in my avatar being one of them...... A 400 Pontiac in my '56 Chevy back in the '70s.

    The die is cast with this last build, however. The 292 inline 6 is going in. I have already modified a Weber intake and Langdon split exhaust manifolds for it and have had Isky grind a cam to my specs in addition to having the majority of parts here for the build.

    Besides, I'm hardheaded. The more of a challenge it is, the more determined I become. :)

    Best regards to you all,

    Harry
     
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