coppercutlass

I got power drums on all corners whats the correct master for my 1972 cutlass. I got a master cylinder from the local parts store made by dorman but im not 100 percent sure its the correct part. Its been installed and seems to work but it seems like finding the correct one is hard as usually most upgrade to disk. I just want to be 100 percent sure i got the correct part. The last master i had on there worked for 8 years but didnt look anything like what i took off which was the original . It was also made by dorman. I had some issues and finally got my brakes to bleed and decided to do all new lines in the front and re bench the master but since im going to have it off and the subject at hand has been bugging me a bit i may as well double check.

Any info would be appreciated.

all i know on the specs is its a 1 in. bore

Fun71

Can't help more than saying the drum masters I have seen have the same size reservoirs front and rear and the disc masters have a much larger front reservoir.

coppercutlass

Thats what i noticed too. and from all the info on parts they share the same 1 in bore. I guess im a little paranoid as i really want it to be right. When i originally did these brake lines and master cylinder i was very green and it worked well for many many years but now i want it to be as correct as i can possibly make it as the car is not only getting a paint job but im addressing a few areas that needed a more professional touch and upgrading.

joe_padavano

The only thing the brake system knows or cares about is the bore and stroke of the M/C. Reservoir size is a convenience for the operator (so you don't have to check fluid level as often) but functionally, so long as there is fluid, the size of the reservoir has no affect on brake performance.

There is one fundamental difference between a drum and disk M/C, and that is the residual pressure valve. An M/C designed for use with drum brakes will have a residual pressure valve in the port(s) designed to operate drum brakes. You can extract this valve to use that port with disc brakes. FYI, there are a lot of replacement M/Cs that are functionally equivalent to stock but look different (like a bolt-on cover).

Here is what the residual pressure valves look like in a drum/drum M/C (items 1 and 2):



To remove the valve, thread a screw into the flare fitting and extract it. The valve and spring fall out of the M/C. Press the flare fitting back in.

RocketDevo

The original code for your 1972 Cutlass drum brake Master Cylinder is "CT"
This code was widely used by all divisions from 1968-1972. All original masters cylinders have bleeders, except for 1971-72 "tall" dual bale manual disc brake cars. I have many cores available if you are in need, or will have rebuilt ones available shortly.

coppercutlass

I would like a price on a rebuilt unit . Who will be rebuilding them

RocketDevo

I have a place in Ontario that remanufactures them completely. The cost depends whether or not they need a stainless steel sleeve. I will know better the cost when I get them back.
Thanks.