Hydraulic System Control Valves: Description: Notes

All vehicles have some type of hydraulic system control valve or switch in the brake system. Unit is usually mounted on left front fender splash shield or frame side rail beneath master cylinder. Valve is connected to master cylinder, wheel cylinders and disc calipers. Combination disc/drum systems use valves which combine warning switch with metering valve and proportioning valve. Vehicles with 4 wheel disc brakes just use a differential warning switch.