The Stovebolt Site Forums The Shop Area The HiPo Shop Firewall Master Cylinder Placement

Hello Stovebolt,

I have a 46 Chevy which I am putting in 350 V8 with 700R4 tranny. I plan on putting in the brake pedal, master cylinder and booster out of a 86 Olds Bravada. After reading other threads, I plan on double walling the left firewall with a donor cab the will fit like a glove and will fabricate bracing to support the pedal bracket under the dash as others have discussed. I plan on putting a universal tilt, steering column in as well. My question is where do you decide to locate your MC through the firewall? Was it a balance of pedal location, clearance and cosmetics in the engine compartment of the MC, etc.? I am using the framework for the pedal assembly out of an S10 and will need to fabricate a pedal the bends horizontally just above the steering column and then bend down vertical again on the right side of the column to have clearance when braking since my pedal is aligned either left or just above the column when mocking up. Since the firewall is stamped where the MC placement would generally be, can a guy just shim or put bushings when mounting the MC to make the mounting flush and be OK?

Any advice is well appreciated!

Thanks,
Bill

What is the advantage of putting the master cylinder on the firewall if you have to support it with all the extra brackets? Just asking......

Hello Joe H,

Biggest reason, because I don't want to crawl under the thing to check the fluid level and also I want to close up my floor and sound proof the cab. I want easy access to check the MC during maintenance checks and bleeding, have a donor SI0 pedal bracket that should work well with minor bracketing for little investment, and feel this would be less fabrication work than trying to put it under the cab anyway. When I talk fabrication, I think this will be minor and will be primarily just between the back of the dash and pedal assembly itself.

Sorry, I failed to mention that it has a front disc brake conversion in the front and drums in the rear.

I'm putting Wilwood remote reservoirs on the firewall.

Was it a balance of pedal location, clearance and cosmetics in the engine compartment of the MC, etc.?

To me I would say yes all the above.
You need to have the booster and master positioned so they're not blocking anything else you need to get to in the engine compartment. Pretty much the same on the inside of the fire wall. It can be kind of a touchy dance getting things just right.

I think pedal location would hold the bigger percentage. You have to be comfortable while driving, especially if you plan on going long distances. It also has to be functional, enough throw, etc. You can't take your foot off the accelerator, then draw your knee up to your face just to be able to put your foot on your brake pedal to stop the vehicle.

I have mine located in the normal position under the cab and I put a remote fill on the firewallExcept mine is stainless steal.

Thanks gentlemen. Luckily Mark, I have short legs and have to reach for the pedals to begin with😂. First time tackling this and didn't know if there was anything else to consider before I start drilling holes in my firewall besides what I already mentioned. I will consider the remote reservoirs, but I think I have my mind made up. They look great by the way, Mick53 and Ron.

I guess my biggest concern is to get a tight, flush fit against the firewall since it is stamped right where I would like to put the MC. After I determine my location is will probably have to shim the mounting bolts either here or there to get it to sit flush with the firewall. Any recommendations on using a 7 vs. 8 vs. 9 inch booster?

Thanks for the insight,
Bill

I would call the manufacturer. For mine Wilwood recommended an 8" duel diaphragm.