Proportioning Valve Description (ABS)

If the vehicle has ABS, the vehicle has a proportioning valve. The proportioning valve limits the hydraulic pressure to the rear brakes in order to prevent the rear wheels from skidding during braking.






Hydraulic Brake System (ABS)






Proportioning Valve (ABS)


Vacuum Brake Booster Description
Power Brake Booster
The booster is located on the bulkhead in the left side of the engine compartment, between the brake pedal and the master cylinder. The booster uses the engine vacuum in order to increase the mechanical force from the brake pedal on the master cylinder pistons.
If the booster becomes inoperable, brake operation will not be lost. The force on the brake pedal will still transfer through the control valve, the booster piston, the piston rod, and the master cylinder pistons. The brake system will still operate but will require greater brake pedal pressure.
DO NOT disassemble the booster. You may adjust the booster piston rod in order to maintain the correct clearance between the booster piston rod and the master cylinder piston. The correct clearance is necessary for the correct operation of the brake system.


Check Valve and Hose
The check valve allows vacuum to flow from the booster to the engine intake manifold. During periods of low engine vacuum or no engine vacuum, the check valve closes and prevents loss of vacuum reserve in the booster.