Maverick and Comet Repair
BRAKES - PRESSURE DIFFERENTIAL VALVE
Centering
Since the
introduction of dual master cylinders to the hydraulic brake system,
a pressure differential warning signal has been added. This signal
consists of a warning light on the dashboard activated by a
differential pressure switch located below the master cylinder. The
signal indicates a hydraulic pressure differential between the front
and rear brakes of 80-150 psi, and should warn the driver that a
hydraulic failure has occurred.
After repairing and bleeding any part of the hydraulic system the warning light may remain on due to the pressure differential valve remaining in the off-center position. To centralize the valve a pressure difference must be created in the opposite branch of the hydraulic system that was repaired or bled last.
NOTE: Front wheel balancing of cars equipped with disc brakes may also cause a pressure differential in the front branch of the system To centralize the valve:
- Turn the ignition to either the "acc" or "on" position.
- Check the fluid level in the master cylinder reservoirs. Fill to within 1/4 in. of the top if necessary.
- Depress the brake pedal firmly. The valve will centralize itself causing the brake warning light to go out.
- Turn the ignition off.
- Prior to driving the vehicle, check the operation- of the brakes and obtain a firm pedal.
