LOAD SENSING PROPORTIONING VALVE (w/o VSC) ON-VEHICLE INSPECTION


  1. CHECK LOAD SENSING PROPORTIONING VALVE ASSEMBLY

    A01E0YR

    1. Set the vehicle to its curb weight.

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

      Standard rear axle load
      Vehicle Type Specified Condition
      2WD Single Cab 7845 N (800 kgf, 1764 lbf)
      2WD Extra Cab 8336 N (850 kgf, 1874 lbf)
      2WD Double Cab 8826 N (900 kgf, 1984 lbf)
      4WD and Pre-Runner 9807 N (1000 kgf, 2205 lbf)

      Note


      • Be sure that the vehicle is on a level surface before starting the procedure.

      • When placing the weights on the vehicle, first place the weights so that the total is approximately 60 kg (132 lb) more than the specification. Then remove weights as necessary to adjust the load.

    3. A01DZ8PE01

      Install SST and bleed air from the brake system.

      SST
      09709-29018
    4. A01DYLOE01

      Raise the front brake fluid pressure to 10000 kPa (107.6 kgf/cm2, 1450 psi) by depressing the brake pedal, and measure the rear brake fluid pressure.

      Standard rear brake fluid pressure
      Vehicle Type Specified Condition
      2WD

      5260 +/-490 kPa (53.6 +/-5.0 kgf/cm2, 762 +/-71 psi)
      4WD and Pre-Runner

      4450 +/-490 kPa (45.4 +/-5.0 kgf/cm2, 645 +/-71 psi)

      Tech Tips


      • The pedal should not be depressed twice or released while raising the front brake fluid pressure.

      • Read the value of the rear brake fluid pressure after raising and holding the front fluid pressure for 2 seconds.

      If necessary, adjust the load sensing proportioning valve.

  2. ADJUST LOAD SENSING PROPORTIONING VALVE ASSEMBLY

    A01E1YBE01

    1. Adjust the length of the No. 2 load sensing spring shackle.

      When the rear brake fluid pressure is below the standard pressure, lengthen length A.

      When the rear brake fluid pressure is higher than the standard pressure, shorten length A.

      Standard Initial Length (A)
      Vehicle Type Specified Condition
      2WD 120 mm (4.764 in.)
      4WD and Pre-Runner 190 mm (7.543 in.)
      Standard Length (A) after Adjustment
      Vehicle Type Specified Condition
      2WD 114 to 126 mm (4.526 to 5.002 in.)
      4WD and Pre-Runner 184 to 196 mm (7.305 to 7.781 in.)

      Tech Tips

      The rear brake fluid pressure changes according to the table below by adjusting length A.

      Standard Pressure Change
      Vehicle Type Specified Condition
      2WD

      Changes by 140 kPa (1.4 kgf/cm2, 20.5 psi) for every 1 mm (0.0394 in.) change in length A
      4WD and Pre-Runner

      Changes by 120 kPa (1.2 kgf/cm2, 17.6 psi) for every 1 mm (0.0394 in.) change in length A
    2. A01DZ28

      If the pressure cannot be adjusted by the No. 2 load sensing spring shackle, loosen the nuts and raise or lower the valve body.

      When the pressure is below the standard pressure, lower the load sensing valve assembly.

      When the pressure is higher than the standard pressure, raise the load sensing valve assembly.

    3. Tighten the nuts.

      Torque:
      13 N*m  { 127 kgf*cm, 9 ft.*lbf }

    4. Adjust the length of the No. 2 load sensing spring shackle again.

      Tech Tips

      If the length cannot be adjusted, check the load sensing valve assembly.

  3. CHECK VALVE BODY


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

      Standard pressure
      Vehicle Type Master Cylinder Pressure Wheel Cylinder Pressure
      2WD

      2450 kPa (25 kgf/cm2, 356 psi)

      1350 +/-200 kPa (14 +/-2 kgf/cm2, 196 +/-29 psi)
      2WD

      5880 kPa (59 kgf/cm2, 855 psi)

      2210 +/-340 kPa (22 +/-3 kgf/cm2, 321 +/-49 psi)
      4WD and Pre-runner

      2940 kPa (29 kgf/cm2, 428 psi)

      1270 +/-200 kPa (13 +/-2 kgf/cm2, 185 +/-29 psi)
      4WD and Pre-runner

      5880 kPa (59 kgf/cm2, 855 psi)

      1720 +/-340 kPa (17 +/-3 kgf/cm2, 250 +/-49 psi)

      If the result is not as specified, replace the load sensing valve assembly.