Description:

This is a Brand New GM Style master cylinder and Prop Valve Kit. These master cylinders feature a 1 1/8" bore(the ports measure 9/16" and 1/2" on each side) -- 1 1/8" bore is the recommended size for Disc Front/Drum Rear applications.  This is a four port master cylinder, so you can use the ports on whichever side you need and block the others.  Mounting hole measurement is 3 3/8" center to center. Master cylinder includes an adapter so it can be used on manual brake applications or with a power brake booster. Also included is a Zinc DISC/DRUM proportioning valve kit (self adjusting valve, lines and bracket to mount kit to the side of the master cylinder). 

The proportioning valve has a zinc finish.  This valve is also called a combination valve, as it performs all of the necessary valving functions with a disc brake conversion.  These functions include the following:

Proportioning:

As more force is applied to the brakes and the car begins to lean forward, less braking force is needed in the rear.  This valve decreases the pressure to the rear, preventing lock up.

Metering:

Metering is used in the front disk brake portion in the disc/drum system to delay application of the front discs allowing the slower reacting drum brakes to catch up.  This provides rear stability on wet surfaces and helps prevent front pad wear.  There is no metering function with the disc/disc setup.

Residual Pressure:

Drum Brakes require residual pressure of 10 lbs. to be held in the line.  This pressure keeps the brake shoes close to the drums giving you a more firm pedal feel.  The disc/disc setup does not require this pressure.

System Failure Switch:

This valve has a system failure switch that will alert you when half of your braking system is not working properly.

    Package includes: 

    Zinc Bail Top 1" Bore Master Cylinder

    Disc/Drum proportioning valve Kit

    Professional Installation is Highly Recommended (No Instruction and Wiring Diagram Included)