B body disc brake conversion kit

i got a question for you guys. I have a 66 Coronet 550 with a 440. I had a CPP front disc brake 11 inch conversion kit put on last week. Im still running the drum master cylinder and he told me I need a proportioning valve which I completely over looked. My shop told me I may need a different master cylinder, I do not want a booster on this car. So do I just need to get a master cylinder for something with front discs? And ive thought about just switching to discs on the rear too. Anyone run 4 wheel discs and do I need a booster if I go that route? Just want to make sure its done right and safe. Thanks guys! Anyone?

I don't know what a CPP kit so it is a little hard to know what you're working with. Some kits are okay but others are crap so hopefully you ended up with a good kit. The best bet for a car like yours is to just use factory parts. If you have 15 inch wheels you should be able to use the factory 11.75 rotors. If you have the 11.75 rotors then the system should work okay without a booster. If you have the big factory drums on the rear the setup will work even better. I wouldn't recommend rear disc brakes for your car.

Spend some time on the Doctor Diff website and you'll see what you need.

Yes, if for no other reason, to get rid of the residual pressure valve in the current MC. A manual disc brake MC from a later Mopar B-body would be a good choice. The need for a prop valve can be determined after the conversion is done. Install a prop valve only if you suffer from premature rear brake lockup.

It does have a dual manual master cylinder on it right now. I did away with the suicide master cylinder about 8 years ago.

Yes, but it it's a drum brake MC it has a RPV in the front circuit which is incompatible with discs.

I believe I used an early to mid 70s A-Body disc brake MC with a 15/16" bore.

That MC might be okay. Drive the car and see what you think. You'll most likely need a prop valve since otherwise the rear drums will lock up during hard braking.

The problem with brake swaps is that people don't have a lot of "common knowledge" around what works and what doesn't. People kind of know which cam works with which engine and stuff like that but which master cylinder works with which rotor size and how much brake bias there should be and stuff like that isn't common knowledge. So when you start swapping parts around you have to either copy a factory setup, or be prepared to do some R&D.

We use 70 C body disc masters.Mine on my 65 has been on for 20 years.Used the same on my kids 62 300 with power drums just used a drum master.Mine is non power disc frt.I run a later 5th ave PP valve.Rocky

Yup, a 1975 Duster with power disc brakes has a 15/16" bore. Use that with your manual setup.

just make sure the master you use has some kind of accuator rod retention so it doesn't pop out when you apply the brakes.

i have been looking but cant seem to find one anywhere

Where are you looking?

Found it first try

Check with Dr. Diff . . . Cass will know or have exactly what you need . . .