Master cylinder questions

[racerx23]

Hi members, I have a1972 demon with the 4 piston power brake setup from the factory. My question is does anyone know if I can convert this to a manual brake system while still using the factory caliper and drum setup. Thanks Bob

 

[TrailBeast]

All it really takes is a master with a smaller piston bore so you can still stop the car.
One of these guys surely has a specific part number or recommendation, since most big block swaps require removing the power steering.

 

[lilnoah]

Contact Cass at Dr Diff he can help you.

 

[racerx23]

Thanks I'll give him a try

 

[KosmicKuda]

Just go to your regular parts store and order a disc brake MC for a 73-75 A body. Get one for power brakes but run it manually. The bore is 7/8. Remove the old junk and bolt this on. You will also need to come up with a manual brake pushrod.

 

[mvh]

Kosmic is right. But you could keep using your same master cylinder if you could find a manual brake pushrod -- the master cylinders are completely interchangeable between power and manual, and yours should have the 15/16" bore which is preferred for manual brakes. Just remove the booster. Factory manual brakes used a 1-1/32" bore which made for a very heavy pedal. The 7/8" bore Kosmic mentions is a size used in later models and B bodies, and it would work perfectly fine as well -- the Mopar disk brake MCs are all basically interchangeable.