As you consider the cause of any of the problems above, it is essential to add the metering valve to the list of possible reasons for the above issues. The symptoms produced by failed metering valves will depend on the type of failure and type of vehicle. Here is a description of each type of failure:
1 – Valve stuck OPEN: If the valve is stuck open, the vehicle will have instant-on front brakes (See figure 48.1). The front brakes will apply instantly, while the rear brakes will have to “play catch up.” The long-term symptom of instant-on front brakes is premature front pad wear on all pads. Depending on the vehicle, this condition may also cause the vehicle to nose dive when stopping. This symptom does not always present itself with valve failure.