Brake Proportioning Valves balance front-to-rear braking by controlling hydraulic pressure. Under light pressure, full hydraulic pressure is allowed to both brakes. Above a certain pressure, the valve reduces pressure to the rear brakes to prevent skidding. If rear wheel skids occur under hard braking, the valve may be defective and should be checked by a professional. Special gauges are needed for diagnosis. Replacing the valves can be done by raising the rear of the vehicle, locating the valve assembly, loosening the
Brake Lines, and removing the valve and bracket. After installation, bleed the brakes and test before normal operation.