I have a manual disk brake master on my duster. Its a reman unit and it works properly however when driving the car, fluid sloshes out of the top (I think).

Thank god I'm using DOT 5!!!

Anyway, I tried different covers and a different rubber gasket with no change.

So I pulled the master and thinking that the rim on the top was pitted I "machined" the top with sand paper on a granite block. As it cut I could see gaps where it was uneven and stopped only when I go all clean metal.

I crimped the bail wire to shut tighter.

The darn thing still leaks!!! Any tips. I don't know where to go from here.

The master is bad get a new one. Its leaking internally over filling one of the reservoirs and pushing fluid by the cap.

Is there anything unique about the 1972 A body system?

I ask this because I've read a couple threads with this same concern, they were also 72.

Had a Dart years ago. Many attempts at solving the same issue. It was also a power brake 72.

Try to get a new one not a reman. A few years back I had to replace the 100,000 plus mile original on my chrysler got a reman from napa and in a week or so it started leaking from the lid and the back where it bolts to the booster. Took it apart and found pits and wear marks in the bore, the core was no good they just put new seals in and ran a hone through it. Get a new bendix if available.

We had the same thing on the AAR, put two different re-man units on. We bought a brand new one and haven't had a problem since.

I popped the cover last night, that was untouched after my testdrive following the resivoir resurfacing. Both resivoirs are level.

If it was transfering fluid by way of a bad piston and overfilling one resivoir, wouldn't one be filled to the brim??

I think I am going to replace it to get a smaller bore master to help with pedal effort anyway. I'll get a new one and hopefully be done with it.

Had the same problem with mine, made a new gasket out of cork, tracing the reservoir outline as a template, no more leaks.