PT Cruiser L4-2.4L (2008)
Brake Proportioning/Combination Valve: Testing and Inspection
PROPORTIONING VALVE
NOTE: Only vehicles without antilock brakes have proportioning valves. Vehicles with antilock brakes have Electronic Variable Brake
Proportioning (EVBP) which is built into the ABS Integrated Control Unit (ICU).
If premature rear wheel skid occurs on a hard brake application, it could be an indication that a malfunction has occurred with one of the proportioning
valves (1, 3).
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.
Before testing the proportioning valve in question, inspect the rear brake linings for contamination or for replacement shoes not meeting the OEM brake
lining material specifications.
The proportioning valve should always be tested prior to being replaced.
The in-line proportioning valves used on this vehicle require special pressure fittings to test the proportioning valves for proper proportioning valve
function. The pressure fittings are installed before and after the proportioning valve being tested to verify proportioning valve is maintaining the required
hydraulic pressure to the rear wheel brake which it controls.
PROPORTIONING VALVE TEST
The test procedure is the same for either rear proportioning valve. After road testing the vehicle to determine which wheel skids first, follow the
procedure below for testing the suspect proportioning valve.
1. Using a brake pedal holding tool as shown, depress the brake pedal past its first one inch (25 mm) of travel and hold it in this position. This will
isolate the master cylinder from the brake hydraulic system and will not allow the brake fluid to drain out of the master cylinder reservoir.
