Check the listing for details. Universal Black GM Disc Disc Brake Proportioning Combination Valve 4 Wheel Disc. Condition: New. Listed at 36.61 USD. Universal Black GM Disc Disc Brake Proportioning Combination Valve 4 Wheel Disc Description:Brand new Black Proportioning Valve. This combination proportioning valve is for Disc/Disc applications. This valve performs all the necessary functions when using disc brakes in the front and disc brakes in the rear.This valve will reduce braking pressure to the rear when necessary to prevent the brakes from locking up. It also distributes the brake pressure evenly so that each brake is working evenly. Finally, this valve offers the brake warning light switch to alert you if there is any failure in the braking system.This valve is a great upgrade over the original and is a must when upgrading to 4-way disc brakes. This is a GM style valve, but will work on almost any Ford, Mopar, Chevy, or whatever, as long as you have the right fittings. Package includes: As shown in our pictures P Professional Installation is Highly Recommended (No Instruction and Wiring Diagram Included)