Relocating brake master cylinder off firewall

[enigma57]

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

[chevynut]

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.

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Here's what I did with HEMI55

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[chevynut]

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

[NickP]

Nice response to an all too often issue

[Gmvette]

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.

[scorpion1110]

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.

[Rick_L]

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.

[NickP]

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.

[chevynut]

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/1007sr-abs-electric-power-brake-system/

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

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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.

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[Custer55]

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.

[Custer55]

Probably not room under the dash for these but another option to keep the master cylinders out of the engine compartment.

https://www.speedwaymotors.com/AFCO-Tri-Reverse-Mount-Master-Cylinder-Pedal-Assembly-Kit-6-2-1,38822.html

[enigma57]

Thanks to all who have posted here! Excellent ideas and I really appreciate the pics. Regarding the hydroboost option...... All of them I have seen in OEM installations have the cylinder on the engine side and I was going to ask if the unit can be clocked (rotated) so as to move the cylinder away from the engine to gain clearance. Thanks to Laszlo for pics of hydroboost with cylinder in 2 o'clock position......



I might mention that besides retro-fitting a hydraulic master and slave cylinder to operate the clutch (bad knees + Langdon split exhaust manifolds drop right into the OEM '57 mechanical clutch linkage)...... I am looking at ways of adding a servo assist (booster) to the hydraulic clutch setup, as well. Might consider hydroboost for both brakes and hydraulic clutch if there is room to do so. Have no plans to add power steering to the '57, but could mount a power steering pump just to serve the 2 hydroboost units if I go that way. What do you think?

Found some pics of mods to my 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.

Inboard half is unmodified......



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



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......

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

Best regards to all,

Harry

P.S. >>> I will also take a look at relocating pedals and master cylinders under toe boards. But if I can work out clearance issues whilst keeping hanging pedals on firewall, will do that. Thankfully, the engine will torque over towards the passenger side under hard acceleration. But with the 292 trial fitted, I have less than 1/2" clearance from Weber intake to OEM '57 (non-power) brake master cylinder with 292 engine in same position as the 235 it will replace. And that is without allowing much needed space to fab and mount throttle linkage for the 3 Weber carbs.

FWIW...... With this type intake on an inline 6, carbs must be mounted with throttle shafts parallel to the crankshaft. And in order to position fuel bowls of the DCNF carbs inboard so adjusting screws will be outboard and accessible, the direction of linkage pull must change 90 degrees (from front to back and then to outboard side pull)...... And then reverse 180 degrees in the side pull to allow mounting carbs with floats inboard.

I may be able to 'fudge' a bit when fabbing the front engine mounts to shift the 292 an additional 1/4" towards the passenger side, but that's about it without butchering the firewall and trans tunnel. In any case...... It will be tight with both intake and exhaust on the drivers side. But I'll get it done one way or the other. Many thanks for your help and ideas, guys!

[Al_Dente]

Probably not room under the dash for these but another option to keep the master cylinders out of the engine compartment...

There's also the option of relocating the master cylinder and booster (for whoever is using one) somewhere else in the vehicle. Some sportscars used to and maybe still do mount a sort of primary master cylinder at the pedal of which operates the secondary master through a slave cylinder. The system operates like a hydraulic-operated clutch. But, instead of having the clutch, the secondary master cylinder fitted in its place.
Here's an example on a Jaguar. I'm assuming that the right-hand drive versions keep the secondary master right where this one has it, simultaneously being operated by the primary master of which would have been located on the opposite side of the firewall where the pedal assembly would otherwise have been mounted:

Case in point: I've got this small 3-wheeler of which the brakes need a boost, especially when the vehicle's loaded:


What i now have is a single circuit master cylinder operating the reaqr wheels. What I want to do is to mount a vaccuum contraction tank and a remote master cylinder with booster outside of the cabin underneath. The set-up would look sort of like the following. This is also my current master cylinder of which I plan on using it as the primary:

[BamaNomad]

Welcome Al Dente! we're glad to have you hear and look forward to your posts about your '56's in Germany!

[Al_Dente]

Thanks for the welcome. I didn't have any American cars here.
My Chevies were my first cars. I bought the rustbucket Bel-Air at 15. It looked like an elderly person's car. nothing at all was modified. The engine ran as smooth as silk, until I attempted quieting down the tappet noise, through messing with the rocker adjustment. It never ran smooth since. There was plenty of crust under the valve cover. So, I suspect that poil changes didn't take place routinely. Then again, it didn't have a PCV valve yet.
Before I got my license, I used to get a kick out of starting it up and driving it up and down the driveway. The tube radio sounded better than anything newer. I can remember the hefty bass tone. I would munch on Reese's Peanut Butter Cups, while sitting in the car listening to the radio. Even, during that year's Michigan winter.
I then saw an add in the newspaper for a 210 body sitting in Troy, not that far from my parents house. It was supposedly a Tennessee body. It was pretty much rust-free with light surface rust spots. It had been primered. I can't remember if the primer covered the original paint or had the previous owner primered a sanded-down car.
I then rented a cherry picker and dropped my drivetrain into the body shell, as well as mounting the Bel-Air trim.
A buddy of mine on the next block got the original 265 from me. He might still even have it. I've got his adress, if anyone's interested. I replaced it with a 283 of which I can't remember as to where I got it from. I rebuilt it in highschool voc auto and dropped it in. I never finished the car.
One day, a co-worker's girlfriend wanted to drive it. She immediately wrecked my front end. I then bought one from a '55 of which the owner didn't need anymore, since he mounted a fiberglass '55 front end on his gloss black 2-door. I can't remember if it was a sedan or not. I'm almost sure that his was a hard-top. He ran a built 302 in it. It also got up and ran pretty good.
I was just driving it and even delivered pizzas in it. I eventually sold it as a basket case, before going to Europe.
I had pleasant memories, during owning it