Checking Brake Proportioning Valve

This proportioning valve, designed to work in conjunction with ABS unit, is located on bulkhead, and regulates distribution of fluid pressure to rear brakes. Using two brake pressure gauges, one on input side and other on output side of proportioning valve, measure pressure with appropriate brake lines disconnected, using following steps:

1. With brakes applied, measure input and output pressure. If measured pressures are within ranges as illustrated, proportioning valve is good.
2. Connect brake lines in their original positions and bleed system. If proportioning valve requires replacement.