Proportioning Valve
NOTE:
Under normal conditions, input and output pressures increase gradually (but not equally) as brake pedal is pressed. At a certain point, output pressure begins to drop while input pressure continues to increase. This point is referred to as the split point.
- Connect 2 pressure gauges, one to input side and one to output side of proportioning valve. Bleed air from brakeline and pressure gauges.
- Gradually press brake pedal and observe pressure gauges. If split point occurs at specified pressure, go to next step. See SPLIT POINT PRESSURES table. If split point does not occur at specified pressure, replace proportioning valve.
- Gradually press brake pedal until input pressure is as specified in INPUT-TO-OUTPUT PRESSURE COMPARISON table. Maximum difference in output pressure between right and left brakelines is 57 psi (4 kg/cm2 ). If output pressure is as specified, proportioning valve is okay. If output pressure is not as specified, replace proportioning valve.
SPLIT POINT PRESSURES
| Application | psi (kg/cm2 ) |
|---|---|
| With ABS | 391-462 (27.5-32.5) |
| Without ABS | 320-391 (22.5-27.5) |
INPUT-TO-OUTPUT PRESSURE COMPARISON (1)
| Application | Input Pressure - psi (kg/cm2 ) | Output Pressure - psi (kg/cm2 ) | ||
|---|---|---|---|---|
| With ABS | 996 (70) | 569-640 (40-45) | ||
| Without ABS | 925 (65) | 462-533 (32.5-37.5) | ||
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