Brake Proportioning/Combination Valve: Testing and Inspection

PROPORTIONING VALVE FUNCTION TEST





1. Connect two pressure gauges, one each to the input side and output side of the proportioning valve, as shown.
2. Air bleed the brake line and the pressure gauge.
3. While gradually depressing the brake pedal, make the following measurements and check to be sure that the measured values are within the allowable range.

Standard Value:

1. Output pressure begins to drop relative to input pressure (split point).

Standard Value:

2. Check that the output fluid pressure is at the standard value when the input fluid pressure increases according to the table provided.
3. Output pressure difference between left and right brake lines.
Limit: 0.4 MPa (57 psi)
4. If the measured pressures are not within allowable ranges, replace the proportioning valve.