I bought a 71 cutlass with manual drums and the master cylinder was completely locked up so replaced it with a master cylinder off a 1970 Buick skylark that was used for power drums (I'm guessing it was used for drums by looking at the top cover). So after replacing the MC I went ahead and replaced the whole assembly spindle and all with another set of drums I had laying around from my other cutlass that were takin off when I swapped to disks so I know they work. All sides were bled pretty well I will add. So my problem is that I can depress the brake to the floor with ease and only one rear tire will barely grab the rest nothing. Also the brake warning light comes on when it's all the way depressed. So is it possible to replace a non power master cylinder with one from a power system or should I just bite the bullet and but a new specific manual drum MC. Thanks for the help once again.

 

The M/C is not your issue. Both power and manual drum brakes used a 1" bore M/C. If the brake light comes on, you still have air in the lines.

 

Ill go ahead and bleed them again,just not looking forward to it because they put the bleeder screw in the hardest to reach place possible! Think I'm finally going to give in and buy a brake bleeding tool so I can do them by myself.

 

I strongly recommend one of the vacuum bleeders that uses your air compressor. They are pricey but since I got mine, I've never had to go back a second time to bleed the brakes. I don't even have to bench bleed the M/C - this unit will pull all the air out of the system from the wheel bleeder screws. I have lot of cars, so I end up using this a lot (and it gets borrowed a lot, too...).