GSIC - Global Service Information Center

# LOAD SENSING PROPORTIONING VALVE > ON-VEHICLE INSPECTION

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1. CHECK LOAD SENSING PROPORTIONING VALVE ASSEMBLY

1. Set the vehicle to its curb weight.

1. Place weights (as necessary) on the rear deck until the rear axle load is shown below.

   Standard:

     Vehicle Type | Rear Axle Load
     2WD Single Cab | 7,845 N (800 kgf, 1,764 lbf)
     2WD Extra Cab | 8,336 N (850 kgf, 1,874 lbf)
     2WD Double Cab | 8,826 N (900 kgf, 1,984 lbf)
     4WD | 9,807 N (1,000 kgf, 2,205 lbf)

   NOTICE:
   1. Be sure that the vehicle is on a level surface before starting the procedure.
   2. When placing the weights on the vehicle, first place approximately 60 kg (132 lb) above the specification. Then remove weights as necessary to adjust the load.

1. Set SST, and bleed air from the brake system.

   SST
     09709-29018

1. Raise the front brake fluid pressure to 10,000 kPa (107.6 kgf/cm2, 1,450 psi) when the brake pedal is depressed, and measure the rear brake fluid pressure.

   Standard:

     Vehicle Type | Rear Brake Fluid Pressure
     2WD | 5,260 +- 490 kPa (53.6 +- 5.0 kgf/cm2, 762 +- 71 psi)
     4WD | 4,450 +- 490 kPa (45.4 +- 5.0 kgf/cm2, 645 +- 71 psi)

   HINT:
     The pedal should not be depressed twice or released while the specified pressure is being set. Read the value of the rear pressure after adjusting and holding the specified fluid pressure for 2 seconds.
   If necessary, adjust the load sensing proportioning valve.

2. ADJUST LOAD SENSING PROPORTIONING VALVE ASSEMBLY

1. Adjust the length of the No. 2 shackle
   For lower pressure - Lengthen "A"
   For higher pressure - Shorten "A"

   Initial set:

     Vehicle Type | "A" length
     2WD | 120 mm (4.764 in.)
     4WD | 190 mm (7.543 in.)

   Adjusting:

     Vehicle Type | "A" length
     2WD | 114 to 126 mm (4.526 to 5.002 in.)
     4WD | 184 to 196 mm (7.305 to 7.781 in.)

   HINT:
     The rear fluid pressure changes to the value on the table below by adjusting the length of "A".

   Vehicle Type | For 1 mm (0.039 in.) of the "A" length
   2WD | 140 kPa (1.4 kgf/cm2, 20.5 psi)
   4WD | 120 kPa (1.2 kgf/cm2, 17.6 psi)

1. If the pressure cannot be adjusted by the No. 2 shackle, raise or lower the valve body.
   For lower pressure - Lower the valve body
   For higher pressure - Raise the valve body

1. Tighten the nuts.

   Torque:
     12.5 N*m{ 130 kgf*cm , 9 ft.*lbf }

1. Adjust the length of the No. 2 shackle again.

   HINT:
     If it cannot be adjusted, check the valve body.

3. CHECK VALVE BODY

1. Check that the master cylinder rear pressure changes according to the rear wheel cylinder pressure.

   Standard:

     Vehicle Type | Master Cylinder Pressure | Wheel Cylinder Pressure
     2WD | 2,450 kPa (25 kgf/cm2, 356 psi) | 1,350 +- 200 kPa (14 +- 2 kgf/cm2, 196 +- 29 psi)
     2WD | 5,880 kPa (59 kgf/cm2, 855 psi) | 2,210 +- 340 kPa (22 +- 3 kgf/cm2, 321 +- 49 psi)
     4WD | 2,940 kPa (29 kgf/cm2, 428 psi) | 1,270 +- 200 kPa (13 +- 2 kgf/cm2, 185 +- 29 psi)
     4WD | 1,720 kPa (59 kgf/cm2, 855 psi) | 1,720 +- 340 kPa (17 +- 3 kgf/cm2, 250 +- 49 psi)

   If the result is not as specified, replace the valve body.