How does a GM proportioning valve work?
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.
How does a brake proportional valve work?
A proportioning valve is a valve that relies on the statics to supply a reduced pressure to an output line. A simple example is where spring load applies a reducing force so that the output pressure is reduced. Proportioning valves are frequently used in cars to reduce the brake fluid pressure to the rear brakes.
How do you get a proportioning valve to work?
Bleed the rear brake line again at the proportioning valve, as you did before if you still have a brake dash light. Bleed the front brake lines on the proportioning valve in the same fashion. This reversal of pressure will eventually break the spool loose inside the proportioning valve, equalizing the pressure between the front and rear brakes.
What to do if your brake proportioning valve is not working?
Inspect the brake pressure. If the pressure is restored to the brake line and your brakes seem to be working properly again, then the reset button worked. If the proportioning valve needs to be reset, brake fluid will not be getting through to the brakes.
How can I tell if my car has a proportioning valve?
With the person safely away from the vehicle, drive the car and make a few medium to hard stops. Make sure to press the brake several times to simulate an emergency stop. If the rear wheels lock up and the front wheels turn normally, there is an issue with the proportioning valve. This test should be performed with extreme caution.
How do you get a proportioning valve unstuck?
Apply the emergency brake and lift the hood. Unscrew, or unsnap the master cylinder cap and fill the master cylinder with brake fluid to the top limit line. Leave the cap off. Use a floor jack to raise the vehicle at the front end and place two jack stands under the frame near each wheel.
Bleed the rear brake line again at the proportioning valve, as you did before if you still have a brake dash light. Bleed the front brake lines on the proportioning valve in the same fashion. This reversal of pressure will eventually break the spool loose inside the proportioning valve, equalizing the pressure between the front and rear brakes.
Inspect the brake pressure. If the pressure is restored to the brake line and your brakes seem to be working properly again, then the reset button worked. If the proportioning valve needs to be reset, brake fluid will not be getting through to the brakes.
With the person safely away from the vehicle, drive the car and make a few medium to hard stops. Make sure to press the brake several times to simulate an emergency stop. If the rear wheels lock up and the front wheels turn normally, there is an issue with the proportioning valve. This test should be performed with extreme caution.
Apply the emergency brake and lift the hood. Unscrew, or unsnap the master cylinder cap and fill the master cylinder with brake fluid to the top limit line. Leave the cap off. Use a floor jack to raise the vehicle at the front end and place two jack stands under the frame near each wheel.
