Anti-Lock Brake System: Operation: Modulator

Modulator consists of ABS motor and pump, accumulator, pressure switch, 3 solenoid valves, 4 pistons and related components. Each solenoid valve set consists of an inlet and outlet valve. Individual pistons and solenoid valve sets are used for the front wheels. Individual modulator pistons are used for each rear wheel, but are connected to a single solenoid valve set used for both rear wheels. The modulator pistons for the rear brakes have proportioning control valves to prevent rear wheel lock-up if ABS system malfunctions.