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I am looking for some advice for my V8 car. I have Scarebird adapters and GM metric calipers front and rear. I was looking at an '82 monte carlo master (small dia. new, and pretty cheap) This master was originally used on a disc drum car. Sound reasonable? Cheers, Dave

Dave, you don't want a master cylinder from a mixed system (drum/disc). The drum reservoir would be smaller since the drum wheel cylinders have a much smaller volume. If you're looking for a maaster cylinder for Disc/Disc, look to the late 60's/early 70's Corvettes. The brake booster would be something entirely different. I believe the Corvette unit has a fairly large diameter, and obviously the mounting bracket would be Corvette specific. If you have fabrication skills, it should be easy to overcome, otherwise, you may need to look to the aftermarket for a 7" diameter booster.

I haven't made it that far in my set-up yet, but I've already decided I am going to be moving the firewall forward to accomodate my 34" inseam.

Dave, you may want to see what I did 10 years ago with my 4-wheel disc system and power brake booster. Here's what I wrote:


A manual dual master cylinder was installed as a brake system update when the engine work and restoration was done in 1995. Braking is slow and the pedal pressure required for quick stops is excessive. For autocrossing an additional update is necessary.

The old master cylinder was replaced with a BM1746 GM 7” dual diaphragm booster with dual master cylinder. The cylinder has a 1-1/8” bore and can be used with either two or four wheel disc brakes. The booster was supplied by Master Power Brake, Mooresville, NC and was designed for 1964-72 GM mid size cars and the 1967-69 Camaro/Firebird.

Jack Brown Engineering, Louisville, KY performed the change over. The 7” booster was installed without modifications to the firewall or inner fender. The clevis pin was connected to the existing hole in the pedal without modification. A custom bracket was fabricated to shim the booster to the firewall. The shim was used mainly to provide clearance for the master cylinder with the underside of the hood. Vacuum to the booster is provided via a 3/8” diameter rubber fuel hose to avoid later problems with hose collapse. The engine had no problem providing 18 inches of vacuum without a reservoir. An adjustable proportioning valve is located on the master cylinder and a balance block was installed on the inside firewall above the throttle pedal (part number and manufacturer unknown).

The booster modification provides an impressive improvement in braking with reduced pedal pressure. The next step will be the replacement of the front stock drum brakes with disc units for ultimate stopping power.







Booster Master Power Brake, 110 Crosslake Park Road
Mooresville, NC 28117
888-533-1199

Thanks for the replies! I have a booster master from a '93 Camaro that I will check out for specs. I think it will work, just have to deal with clearance. Will try shimming, sounds good. Cheers, Dave