Brake Proportioning/Combination Valve: Testing and Inspection

LOAD SENSING PROPORTIONING AND BY-PASS VALVE (LSP & BV)

CHECK AND ADJUSTMENT OF FLUID PRESSURE





1. SET REAR AXLE LOAD
Rear axle load (includes vehicle weight): 1,050 kg (2,310 lb)





2. INSTALL LSPV GAUGE (SST) AND BLEED AIR
(SST 09709-29017)





3. RAISE FRONT BRAKE PRESSURE TO 7,845 kPa (80 kgf/cm2, 1,138 psi) AND CHECK REAR BRAKE PRESSURE

Rear brake pressure: 4,727 ± 490 kPa (48.2 ± 5 kgf/cm2, 686 ± 71 psi)

HINT: The brake pedal should not be depressed twice and/or returned while setting to the specified pressure. Read the value of rear brake pressure two seconds after adjusting the specified fluid pressure.

If the brake pressure is incorrect, adjust the fluid pressure.

4. IF NECESSARY, ADJUST FLUID PRESSURE





(a) Adjust the length of the No.2 shackle.
Low pressure - Lengthen A
High pressure - Shorten A

Initial set: 78 mm (3.07 in.)
Adjusting range: 68 - 88 mm (2.68 - 3.46 in.)

HINT: One turn of the nut changes the fluid pressure about 137 kPa (1.4 kgf.cm, 20 psi).





(b) In event the pressure cannot be adjusted by the shackle, raise or lower the valve body.
Low pressure - Lower
High pressure - Raise

(c) Torque the nuts.
Torque: 13 Nm (130 kgf.cm, 9 ft.lbf.)

(d) Adjust the length of the No.2 shackle again.
If it cannot be adjusted, inspect the valve housing.

5. IF NECESSARY, CHECK VALVE BODY





(a) Assemble the valve body in the uppermost position.

HINT: When the brakes are applied, the piston will move down about 1 mm (0.04 in.). Even at this time, the piston should not make contact with or move the load sensing spring.





(b) In this position, check the rear brake pressure.





If the measured value is not within standard, replace the valve body.