The Stovebolt Site Forums The Parking Lot Big Bolts Dual master cylinder

I have a 1950 Chevy 4400 , I want to replace the single master cylinder and use dual chamber m. c. so what year m. c. should I get at auto zone? I know I will have to fabricate a bracket for it.

Hy Joe Alan, will you be keeping drum brakes all around or will there be other modifications to the braking system?

All drums and it does not have a booster on it. I don’t know if that makes a difference though. No other modifications.

Just make sure the dual MC has the same size bore as your original (1-1/4" I believe). Don't use a car MC as they won't push enough fluid to your bigger wheel cylinders.

Mike B

I think if you are changing to a dual MC, you may want a bit smaller diameter than the original, because you are not pushing to all 4 wheels with one chamber, but splitting them. As Mike B stated though, if you use one that is the same diameter as original, it should push enough fluid but, may be too hard to push. Smaller diameter, makes it easier to push but, the pedal will travel farther to push the same amount of fluid so, if you go too small, it will hit the floor before stopping you!

Hy again Joe Alan, I found a dual circuit master cylinder with a 1 1/4" bore, it looks like it was designed for a drum/drum system. Raybestos MC36359 $59.79 at RockAuto. I think you'll find your braking effort will be less of an effort if you install a booster in front of the master cylinder. If you look at some of the vendors websites I think you might find kits including brackets.

Sorry for not getting back sooner but I just got back home from having carotid artery surgery. Thank you guys for the help because I hadn’t thought about the bore size .
Do you think I should change the brake line size, since I am replacing them also?
I believe they are 1/4” lines.

Hy Joe Alan, I would not change the original line size, you would just be adding one more adaptation problem into your project.

Thanks 3B for all the help