Grand Voyager V6-3.3L VIN G Flex Fuel (1999)
Brake Proportioning/Combination Valve: Testing and Inspection
With Antilock Brakes
A vehicle equipped with ABS uses a fixed proportioning valve.
On a vehicle equipped with ABS, premature or excessive rear wheel ABS cycling may be an indication that the brake fluid pressure to the rear brakes
is above the desired output.
Prior to testing a proportioning valve for function, check that all tire pressures are correct. Also, ensure the front and rear brake linings are in
satisfactory condition. It is also necessary to verify that the brakes shoe assemblies on a vehicle being tested, are either Original Equipment
Manufacturers (OEM), or original replacement brake shoe assemblies meeting the OEM lining material specification. The vehicles brake system is
not balanced for after market brake shoe assembly lining material.
If brake shoe assembly lining material is of satisfactory condition, and of the correct material specification, check for proper proportioning valve
function using the following procedure:
Rear Brake Proportioning Valve And Brake Tube Locations
1. Road test vehicle to be sure the vehicle is truly exhibiting a condition of excessive rear wheel ABS cycling. Since ABS cycles both rear brakes
together both proportioning valves of the assembly must be tested. Use the following procedure to test the proportioning valve:
2. Remove one of the chassis brake lines coming from the ABS modulator, at the proportioning valve assembly. Remove the hydraulic brake line
going to one of the rear wheels of the vehicle from the proportioning valve.
3. Remove the 2 bolts attaching the proportioning valve to the frame rail.
CAUTION: When lowering the proportioning valve, care must be taken not to kink any of the chassis brake lines.
4. Carefully lower the proportioning valve for clearance to install the proportioning valve test fittings.
Proportioning Valve Test Fitting Installation
