Load-Sensing Proportioning Valve (LSPV) & By-Pass Valve (BPV): Previa

1. For testing purposes, rear axle is loaded to a specified weight. Set total rear axle weight to specified amount. See LSPV REAR AXLE TEST WEIGHT  table.
   NOTE: DO NOT depress brake pedal more than once or release pedal while setting pressure on front gauge.
2. Attach Pressure Gauge Set (09709-29018) to front caliper and rear wheel cylinder or caliper. Bleed air from system. See BLEEDING BRAKE SYSTEM . Depress brake pedal until front pressure is as specified. See LSPV PRESSURE SPECIFICATIONS  table. Wait 2 seconds and record rear pressure reading.
3. Adjust rear pressure by changing length of spring shaft. See Fig 1. To increase rear pressure reading, increase distance "A". To decrease rear pressure reading, decrease distance "A". If valve cannot be adjusted to specification, replace valve assembly.

NOTE: On Previa, for pressure change of 55 psi (3.9 kg/cm² ) on rear disc brakes or 28.4 psi (2.0 kg/cm² ) on rear drum brakes, turn adjustment nut one complete turn (360 degrees).

Fig 1: Measuring LSPV Spring Shaft Length (Previa)

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