How to Install a Brake Proportioning Valve

A brake proportioning valve is located between the master cylinder and the rear brakes on a vehicle. When the brakes are applied to a vehicle, the vehicle's center of gravity is moved forward, which lightens the load on the rear tires. If the brakes were applied equally all the way around, the rear tires would lock up almost immediately because of the sudden weight shift. A brake proportioning valve prevents this from happening by lowering the braking pressure applied to the rear wheels.

Instructions

1

Loosen the rear wheel lug nuts on both wheels with the lug wrench. Raise the rear of the car with the car jack and place jack stands under the rear frame rails of the vehicle. Slowly lower the vehicle down onto the jack stands. Shake the car to ensure that it's resting securely. Finish removing the lug nuts and rear wheels and set them aside.

2

Remove the lines going to and from the brake proportioning valve with the line wrench set. The normal wrench set must be used on the machined edges of the proportioning valve to prevent damage to the brake lines. Throw away the old brake proportioning valve.

3

Inspect the fittings on both ends of the brake lines and clean them with a wire brush as needed. Thread the lines onto the new brake proportioning valve and use the wrench set to support the proportioning valve. Tighten the fittings with the line wrench set, using the wrench set to support the proportioning valve.

4

Pop the hood on the vehicle and remove the master cylinder reservoir cap. Top off the reservoir with the brake fluid until full. Start the engine and have the helper pump the brakes until a firm pedal is attained.

5

Place a drain pan under the rear passenger caliper or wheel cylinder. Tap the bleeder screw with the wrench to break the taper and carefully loosen the bleeder valve until fluid and air expels from the wheel cylinder. Instruct the helper to hold the pedal to the floor until the bleeder screw is tightened. Repeat until absolutely no air expels from the bleeder screw.

6

Place the drain pan under the driver's side rear caliper or wheel cylinder. Repeat the process of the previous step until absolutely no air is expelled from the bleeder screw. Remove the drain pan and dispose of the brake fluid properly.

7

Place the wheels back onto the rear of the vehicle and tighten the lug nuts down by hand. Raise the vehicle back into the air with the car jack and remove the jack stands from underneath the vehicle. Lower the vehicle to the ground.

8

Tighten the lug nuts and torque them down the the manufacturer's recommended torque with the torque wrench. Top off the master cylinder reservoir and apply the reservoir cap. Shut the vehicle hood.