Neon L4-122 2.0L DOHC VIN Y SFI (1998)
Brake Proportioning/Combination Valve: Testing and Inspection
With Antilock Brakes
CAUTION: Proportioning valves should never be disassembled.
Proportioning Valve
If premature cycling of the rear brake ABS occurs on hard brake application, it could be an indication that a malfunction has occurred with one of the
proportioning valves.
Proportioning Valve Location
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 slides first is essential. Once the wheel which is skidding first is determined use the following procedure to diagnose the proportioning
valve.
The test procedure is the same for both rear proportioning valves. After road testing the vehicle to determine which wheel skids first, follow the
procedure below for testing the required proportioning valve.
Brake Pedal Holding Tool
1. Using a brake pedal holding tool as shown depress the brake pedal past its first one inch 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.
2. Remove the chassis brake tubes from the proportioning valve controlling the rear wheel of the vehicle which has premature wheel skid.