Toyota Previa 1991-1997 Repair Information

Proportioning Valve

Print

REMOVAL & INSTALLATION



See Figure 1



Click image to see an enlarged view

Fig. Fig. 1: A proportioning valve has several brake lines leading into it

  1. Disconnectr the brake lines from the valve body.
  2.  
  3. Remove the locknut and disconnect the spring from the lower control arm.
  4.  
  5. Remove the 2 mounting bolts and extract the LSP and BV assembly.
  6.  

To install:
  1. Attach the valve assembly to the vehicle and tighten the bolts to 14 ft. lbs. (19 Nm).
  2.  
  3. Positon the spring on the lower control arm and set the length with the adjusting nut. The initial set length should be 1.18 inch (30mm). Tighten the assembly to 9 ft. lbs. (13 Nm).
  4.  
  5. Connect the brake lines and secure each one to 11 ft. lbs. (15 Nm).
  6.  
  7. Fill the brake master cylinder with fresh brake fluid, then bleed the brake system.
  8.  
  9. Check and adjust the fluid pressure.
  10.  
  11. Test driver the vehicle.
  12.  

FLUID PRESSURE ADJUSTMENT



See Figures 2 through 10

  1. Set the vehicle unladen.
  2.  



Click image to see an enlarged view

Fig. Fig. 2: The Load Sensing Proportioning and By-pass valve with adjuster is located near the rear axle of the vehicle



Click image to see an enlarged view

Fig. Fig. 3: Load sensing proportioning valve (1), by-pass valve (2) and load sensing spring (3)

  1. Measure the rear axle load and note the value.
  2.  



Click image to see an enlarged view

Fig. Fig. 4: Place the vehicle without a load and measure the rear axle load

  1. Set the rear axle load. Standard load is 2028 lbs. (920 kg).
  2.  
  3. Install a Load Sensing Proportioning gauge (SST 09709-29017) and bleed the air from the system.
  4.  



Click image to see an enlarged view

Fig. Fig. 5: Attach brake pressure gauges to the front and rear brakes, then bleed the lines



Click image to see an enlarged view

Fig. Fig. 6: Rear pressure with rear drum brakes



Click image to see an enlarged view

Fig. Fig. 7: Rear pressure with rear disc brakes and without ABS



Click image to see an enlarged view

Fig. Fig. 8: Rear pressure with rear disc brakes and ABS

  1. Raise the front brake pressure to the following specifications and check the pressure of the rear brakes.
  2.  

The brake pedal should not be depressed twice and returned while setting to the specified pressure.

  1. Read the value of the rear pressure 2 seconds after adjusting the specified fluid pressure.
  2.  
  3. If necessary, adjust the fluid pressure:
    1. Adjust the spring shaft length by turning the adjusting nut.

      Low pressure-lengthen A
       
      High pressure-shorten A
       

    2.  
    3. For every turn of the adjuster, the fluid pressure with change by about:

      Rear drum-28.4 psi (196.1 kPa)
       
      Rear disc-55.5 psi (381.5 kPa)
       

    4.  
    5. Tightrn the nut to 9 ft. lbs. (13 Nm).
    6.  

  4.  



Click image to see an enlarged view

Fig. Fig. 9: Turning the adjusting nut to lengthen or shorten the pressure



Click image to see an enlarged view

Fig. Fig. 10: Tighten the nut while retaining the adjusting bolt

  1. Remove the gauge and bleed the brake system.
  2.  
  3. Check for leaks and test drive the vehicle.
  4.  

 
label.common.footer.alt.autozoneLogo