Load Sensing Proportioning Valve (Land Cruiser & Pickups, Except 1/2 Ton)
- Set rear axle load (including vehicle weight) to 1433 lbs. (650 kg) on 4WD pickup, to 2646 lbs. (1150 kg) on Land Cruiser and 1323 lbs. (600 kg) on all others. Install a load proportioning gauge (09705-29017 or 09709-29017) to front caliper and another to rear wheel cylinder on same side of vehicle.
- Depress brake pedal and raise pressure on front gauge to 711 psi (50 kg/cm2 ). Do NOT depress brake pedal more than 1 time and do not release pedal while setting front pressure reading. After 2 seconds, rear brake pressure should be 398-540 psi (28-38 kg/cm2 ) on pickups and 498-611 psi (35-45 kg/cm2 ) on Land Cruiser.
- Depress brake pedal further and raise front brake pressure to 1138 psi (80 kg/cm2 ) on pickups and 1422 psi (100 kg/cm2 ) on Land Cruiser. Rear brake pressure should be 525-725 psi (37-51 kg/cm2 ) on pickups and 725-925 (51-65 kg/cm2 ) on Land Cruiser.
- If pressure readings do not meet specifications, adjust load sensing proportioning valve by adjusting length of lower shackle. See Fig 1. If rear pressure was low, lengthen distance "A". If rear pressure was high, shorten distance. Repeat test procedure and check pressure readings.NOTE: Turning the lower shackle 1 turn changes pressure reading 8.5 psi (.6 kg/cm2 ).
- If rear pressures do not conform to specifications after adjusting lower shackle, loosen valve body retaining nuts and reposition valve body. If rear pressure was high, raise valve body. If pressure was low, lower valve body. Tighten nuts and adjust length of lower shackle to standard length.
- Standard length for 4WD pickup should be 4.72" (120 mm) and 3.07" (78 mm) for all other models. Repeat test procedure and check pressures. If pressures do not meet specifications, position valve body in upper most position and depress brake pedal to obtain readings shown on Load Sensing Proportioning Valve Specifications table. If measured value does not meet specifications shown in table, replace valve assembly.
Load Sensing Proportioning Valve Specifications
| Front Reading psi (kg/cm2 ) | Rear Reading psi (kg/cm2 ) | |
|---|---|---|
| Pickup | ||
| 71 (5) | 71 (5) | |
| 711 (50) | 280-337 (19.7-23.7) | |
| 1138 (80) | 424-509 (29.8-35.8) | |
| Land Cruiser | ||
| 71 (5) | 71 (5) | |
| 365 (25) | 148-205 (10.4-14.4) | |
| 835 (60) | 312-411 (21.9-28.9) | |