Does anyone remember the master cylinders that Richard Ehrenberg was selling here on Moparts? I just want to know if it will work for my application. I have a '71 RoadRunner with manual drum brakes. I'm putting spindles from a '76 A-body with 11.75 rotors and adapters from a R body. I'm not sure if my original master cylinder will work, if not, is this a good choice? My brakes will remain manual.
Thanks,
Jim

A front drum brake master cylinder will not work with a disk brake conversion. That master cylinder should work as will several others. Provided its for a RWD disk brake equipped mopar car with manual brakes made from '73-on it should work well. The old standby could always be one for a '73-'74 Charger/Road Runner with manual brakes.

Does your master have two bolts or four holding it to the firewall?

I have one of Eberg masters on my 65 Coronet and it originally had four bolts holding the master to the firewall, so I needed an adaptor.

Youll need a new proportioning valve when you go to disc brakes, as 4 wheel drums doesnt use one. Adjustable prop. valves are inexpensive.

Mine has 4, I'm not sure what his had, but it did come with an adapter. I also have a proportioning valve to adjust the front and rear. So, if it's the same master. it will be good for my application?
Jim

I stock new, aluminum master cylinder packages with the correct 1 1/32" bore, billet aluminum adapter and push rod retainer.

E-mail me if you are interested.

Yes, you can re-use your old MC push rod. I also make super-duty heim joint style adjustable push rods.

I don't see why not.

Whats the diameter of the shaft that would go into the master? I will measure the master cup.

Off the top of my head, 7/16" diameter shaft machined down to about 3/8" on the ball end.

Thanks,

Cass

I bought one...works but leaks around the caps. Ruined the paint on the inner fenders.

Bought which one from where?
Jim

IIRC all they are is a mid 80's M body or truck master cylinder...should be able to pick one up reasonably from the local parts store or rockauto.com

I have used drum ones on a disc conversion just by removing the residual valve(if it had one). You might try your current one since it is still good, just stick a drill bit deep into the brass seat on the side of the MC closest to the firewall & you'll feel the springy residual pressure valve if there's one in there & remove it if there is. The fluid capacity is less but we are on top of this as opposed to the general motoring public who do not check fluid levels as often as we do. Then you'll know & might save yourself some money & if you then want to change to an aluminum one it must have the recess for the manual brake pushrod & rubber retainer, just make sure you get the bore size thats right for YOUR combination THE FIRST TIME & the adapter plate & you're all set.

...or just get a new disk brake master at any auto parts store. They should still be aval new for a 72 car.

Most auto parts stores do not carry Mopar aluminum master cylinders. Most aftermarket 2 hole masters are cast iron.

If your doing the A-Body disc brake conversion I would not recommend a 1 and 1/32 inch bore master cylinder.

I would go with a 1 inch bore or a 15/16" bore
(Both bores are available in front disc/rear drum master cylinders from Bendix)

Why?

The smaller the bore, the higher the output pressure to the calipers. Your front disc brake calipers will require 1000 psi in order to function properly..

Getting that type of pressure from a 1 1/32" bore
master cylinder will require a VERY HEAVY FOOT...
more than most people are used to or expect.

What happends when the pressure is less than 1000 psi at the calipers?

Well, the brakes just won't seem to grab as well...
your expecting the car to slow down and stop and it won't, you'll have to press your foot harder
to get it to do what you want it to do...
meaning stop!

There is an excellent writeup of this subject on
Master Power Brakes website.. I think it is in the FAQ section on master cylinders...

Before grabbing spindles from 1 car and E'bergs master cylinder.. I would recommend you read up on this first...

Random parts thrown togethe