Save some weight and add some extra room by converting your musclecar over to an aluminum master cylinder. The aluminum master cylinder is smaller and much lighter than the cast iron original versions. The aluminum master cylinders are also more corrosion resistant and less likely to leak from the reservoir.

Magnum HP offers three master cylinder adapters in order to match the most common configurations. The first style has 4 holes in it for cars that have studs protruding from the firewall. The 1973 to 1976 A body cars use this style of master cylinder mount.

The second adapter pictured has 4 studs which mount through the holes in the firewall. This style was used on many B body cars as well as early A bodies.

The third is an offset style that moves the master cylinder over , creating extra clearance for Hemis or other tall valve covers.

These adapters are designed to adapt the later model aluminum master which started to appear in the 1978 model year and was gradually phased in. There are several different bore diameters used in RWD vehicles. We carry a new master cylinders with a 1 1/16" bore. DO NOT use a master cylinder from a FWD car! They appear to be the same but were designed for diagonal braking systems and are not calibrated correctly for rear wheel drive vehicles. The master cylinder adapters are designed to be a direct bolt in replacement for your existing manual brake master cylinder. Except for the offset version ,the thickness of the adapter compensates for the rearward placement of the piston in the aluminum master cylinder. This will allow your existing pushrod to fit without any further modifications.

You MUST use the factory designed rubber push rod retainer when using manual brakes! The master cylinder you use MUST be equiped with a groove machined into the back of the piston to accept the retainer. The new master cylinders we sell come with a new retainer and have the groove machined into the piston. Use of a manual brake pushrod with no retainer can result in TOTAL LOSS OF BRAKES if the pushrod fall out !! If you choose to use a master cylinder that does not have this retainer groove, you MUST fabricate a positive throttle stop to prevent the pushrod from falling out if the pedal is accidentally lifted upward. DO NOT rely on the thin metal bracket that holds the brake light switch !

If you are converting from a power brake system then you may have other issues to solve. Some power brake cars used different pedal assemblies in order to reduce the amount of pressure applied to the brakes. The pushrod for the power brake assembly will not work with the manual master cylinder and there may be issues with how the power booster was mounted to the firewall. In short, if you are converting a power brake car over to manual disc brakes you will most likely need to find other parts to complete the conversion.

Power brakes versus manual brakes: In our experience, there is no need to run power brakes in a musclecar era Mopar. If you have swapped over to the large 11.75 diameter rotors on the front then you will have enough brake torque without using a power booster. We recommend that the power booster be removed from any performance orientated vehicle and the car be converted to manual disc brakes using the aluminum master cylinder. This will provide you with plenty of braking power yet will weigh less and take up less room than the stock system. Manual disc brakes will also eliminate the need for engine vacuum to the power booster which in turn will allow a person to run a slightly hotter cam on the street. Chrysler engineers used manual disc brakes on vehicles as heavy as the D100 pickup truck so we are confident that this is a well engineered solution.

We highly recommend that you read and follow the instructions found in a factory service manual for bench bleeding and replacing a master cylinder.