Ford Thunderbird/Cougar 1983-1997 Repair Guide

Proportioning Valve


On vehicles equipped with front disc and rear drum brakes, a proportioning valve is an important part of the system. On cars through 1988, it is installed in the hydraulic line to the rear brakes. On 1989-96 cars, it is in the control valve assembly. Its function is to maintain the correct proportion between line pressures to the front and rear brakes. No attempt at adjustment of this valve should be made, as adjustment is preset and tampering will result in uneven braking action.

To assure correct installation when replacing the valve, the outlet to the rear brakes is stamped with the letter R .