Master Cylinder

[Kevo]

Hey everyone. I have recently completed a drum to disc conversion on my 1968 dodge dart, and i was wondering if anyone has and recommendations on master cylinders. I found one on rockauto that is specified for front discs and rear drums, has anyone else used this? Think it will work fine with an upgrade to my rear drums?

Front wheels have 9in drum ->disc brakes, rears have 10in drums

Any help is appreciated, thanks everyone!

 

[Inertia]

Hope you installed the proportioning valve,,

You need a M/C specifically for disc, as it won't have a residual pressure valve in the disc circuit.

And the small bore 15/16, for disc, is the M/C to use, especially with manual brakes..

A larger bore M/C could be used with power..

If your old M/C is 15/16 bore, and is good, you can remove the residual press valve from behind the brake line seat, ( the tapered thing that the brake line seats on).

Take a self tapping screw of appropriate size, screw it into seat, pull with pliers, remove the spring and rubber valve, and replace the seat, viola, disc brake M/C..

 

[KosmicKuda]

The typical starting point is to order a 73-75 A-body POWER disc brake MC. This gets you a MC with a 15/16" bore. You can get one at any parts store or Rockauto. But...you will run this manually using the manual drum brake push rod. I did that and the feel was excellent. Unless you have some kind of physical limitation, there is no need for power brakes on an A-body. Power Brakes just add weight, take up more room in the engine compartment, and add more things to break down or leak.

I've also tried a 1-1/8" bore modern Mopar aluminum MC and the pedal was super hard. The car would sometimes creep at traffic lights in gear unless I put both feet on the brake pedal. If you weren't paying attention to keeping a big foot on the pedal, it may lead to trouble with the car in front of you.

I'm currently using a NOS Direct Connection aluminum MC with a 1-1/32" bore. The pedal is stiff but manageable. I eliminated the safety switch/distribution block and just plumbed a tee in its place w/ an adjustable proportioning valve (Wilwood) in the rear line.

The 15/16" bore MC really seemed to give the best result. I'm running 73-76 front discs w/ 10" x 2-1/2" rear drums.

Did you use the 9" knuckle and 9" lower ball joint with some kind of kit? For what it's worth, Ehrenberg says the 9" lower ball joints are very weak and susceptible to failure. Just sayin....