General Testing
CAUTION: Proportioning valves should never be disassembled.Proportioning Valve:
If premature rear wheel skid occurs on hard brake application, it could be an indication that a malfunction has occurred with one of the proportioning valves.
One proportioning valve controls the right rear brake, and the other proportioning valve controls the left rear brake. Therefore, a road test to determine which rear brake skids first is essential.
If a malfunctioning proportioning valve is suspected on a vehicle equipped with ABS brakes, refer to Test Procedure.