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.





1) Output fluid pressure begins to drop relative to input fluid pressure (split point).
Standard value:
<2.4L engine> 3.7 - 4.2 MPa (537 - 609 psi)
<3.0L engine> 3.2 - 3.7 MPa (464 - 537 psi)
2) Check that the output fluid pressure is at standard value when the input fluid pressure indicates 9.8 MPa (1,422 psi).
Standard value:
<2.4L engine> 5.0 - 5.8 MPa (725 - 841 psi)
<3.0L engine> 4.6 - 5.4 MPa (667 - 783 psi)
3) Output fluid pressure difference between left and right brake lines.
Limit: 0.8 MPa (116 psi)
4. If the measured fluid pressures are not within allowable ranges, replace the proportioning valve.