2005 Nissan Altima - Brake Proportioning Valve

The brake proportioning valve controls the amount of braking pressure sent to the front disc brakes and the rear drum brakes. Since the front brakes generate up to 75% of the vehicle's stopping force, equal pressure will not be applied to both the front and rear wheels at the same time. Proportioning valves ensure that most of the braking pressure is sent to the front disc brakes to increase stability and control so the vehicle can be stopped safely.