- Locate the brake proportioning valve near the rear brake line. It will have one or two buttons located on it. ...
- Push the reset button located on the valve with your fingers, which will reset it so the valve is working properly again. Inspect the brake pressure.
How do you unstick a proportioning valve?
Tap the proportioning valve with a tack hammer several times lightly — sometimes this frees up a corroded bore and piston spool inside the valve. Wiggle the brake light warning switch wire on the top of the proportioning valve, making sure it has a tight, clean connection.
How do you test a proportioning valve?
Pressure gauges are the best way to diagnose a failed proportioning valve. There will be a gage installed into the front and rear hydraulic circuits. Start the vehicle, and apply the brake pedal with heavy pedal pressure to duplicate a panic braking situation. The front and rear pressures should be different.
What happens when a proportioning valve goes bad?
Since the proportioning valve decreases the pressure sent to the rear brakes, the main symptom the valve is going bad is the rear wheels locking up when the brakes are applied . Furthermore, the wheels will lock up more easily on wet surfaces. The rear brakes may feel touchy when applied even gently.
Can you adjust a proportioning valve?
Most adjustable brake proportioning valves are very simple devices designed to fit between the master cylinder and the rear brake line. The valve offers a range of adjustment that decreases master-cylinder pressure down to a preset minimum.
How do I know if my proportioning valve is bad?
Since the proportioning valve decreases the pressure sent to the rear brakes, the main symptom the valve is going bad is the rear wheels locking up when the brakes are applied . Furthermore, the wheels will lock up more easily on wet surfaces. The rear brakes may feel touchy when applied even gently.
Can you bypass a proportioning valve?
The valve will only work as designed if the rest of the suspension retains the original specifications – if your car is significantly lowered or the suspension stiffened up, you might as well bypass the proportioning valve.
Will a bad proportioning valve cause a hard brake pedal?
Because the brake fluid can’t be compressed, the pedal becomes rock hard . ... You still can generate moderate pressure on the “good” side of the valve therefore allowing the car to be driven in a limp home scenario.
Can a brake proportioning valve be repaired?
One such repair that can be done by a do it yourself mechanic is replacing a proportioning valve . This valve is important to give each brake the necessary amount of fluid to effectively operate the calipers and pads. When your is leaking, or not working properly, here are the steps necessary to replace it.
How do you bleed a proportioning valve?
The proportioning valve doesn’t have any way to bleed air, so you will have to bleed the front and rear brake lines in order to remove any air trapped in the valve. Park your car on a flat surface and set the emergency brake, to prevent your car from rolling while you are working under it.
How does a proportioning valve equalize braking action?
The proportioning valve reduces the pressure to the rear brakes . If equal braking force were applied to all four wheels during a stop, the rear wheels would lock-up before the front wheels. The proportioning valve only lets a portion of the amount of pressure to the rear wheels thus preventing rear wheel lock-up.
How do you replace a proportioning valve?
The average cost for brake proportioning valve replacement is between $317 and $346 . Labor costs are estimated between $110 and $139 while parts are priced at $207.
How does a GM proportioning valve work?
The proportioning valve reduces the pressure to the rear brakes . ... If equal braking force were applied to all four wheels during a stop, the rear wheels would lock-up before the front wheels. The proportioning valve only lets a portion of the amount of pressure to the rear wheels thus preventing rear wheel lock-up.
Do you have to have a proportioning valve?
Yes . The addition of a proportioning valve is a must. Without it your braking system will not operate properly.
Where is the proportioning valve normally located?
Many proportioning valves are mounted directly in the master cylinder outlet to the rear brakes . Height sensing proportioning valves are connected to the hydraulic lines leading to the rear drums located between the vehicle’s chassis and the rear axle.
