[Warrant]

Im assembling my front disc brakes for my 1972 nova tonight, it uses a custom bracket that mounts rear camaro rotors with front celebrity calipers...the nova now has all drums, will my master cyilinder work without any mods? porportioning valve? residual valve? Thanks!

[poncho62]

The disk/drum M/C has different valving than the drum/drum........I would imagine the proportioning valve is different also.

[67 Deuce 4 Me]

I asked the guys at Scarebird about this and thay said drum drum master would be ok. Thats what I have on mine now and it works fine. They said that I wasn't pleased with the stopping power to switch to a disk drum master and proportioning valve.

[Warrant]

I see, I will use my current MC, if Im not satisfied Ill look for a new power booster setup. Those scarebird brackets are really slick ehh... Thanks!

[302 Z28]

I did something similar years ago when I converted my 69 Camaro to front disks. I did not initially use a MC for disk brakes. It stopped OK, a little better than drums, but not what I expected disks to do. The original MC went south so I opted for a Corvette MC with front disks and rear drums, along with the proper proportioning valving. The difference was night and day, all of a sudden my Camaro had vastly improved braking.

Vince

[IanRiordan]

Drum brake master cyls generally have a non return valve behind the brass cone in the m/c outlet. If you convert from drum to disc on either or both axles you must lose this valve (spring and split rubber cup.)
Disconnect the appropriate brake line, screw a self tapper into the cone and using a pair of side cutters pry it out. discard the valve, refit the cone and bleed brakes.
The valve is only there to maintain fluid at the wheel/cyls - calipers don't have return springs.