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Proportioning Valve Test (Models With Abs)

NOTE: A premature rear wheel skid during hard braking may be caused by a defective proportioning valve. Proportioning valve is divided into 2 separate systems, one system for right rear brake, and one system for left rear brake.
  1. Ensure all tires are properly inflated. Ensure all brakes are in good condition and brake linings are within specification. If all conditions are satisfactory, go to next step. If all conditions are not satisfactory, correct as necessary and go to next step.
  2. Road test vehicle to ensure vehicle is exhibiting premature rear wheel skid by excessive rear wheel ABS cycling. ABS cycles the brakes on both rear brakes together, so both valves on proportioning valve must be checked.
  3. Disconnect one ABS module-to-proportioning valve brakeline from top of proportioning valve. Proportioning valve is located on outside of driver's side frame rail, in front of rear axle. Remove brakeline for one rear brake from front of proportioning valve.
    4. CAUTION: Note location of proportioning valve-to-frame rail bolts for installation reference. Bolts must only be installed in the 2 front holes on mounting bracket for proportioning valve.
  4. Remove proportioning valve-to-frame rail bolts. Carefully lower proportioning valve. DO NOT bend brakelines. Install Pressure Test Fitting (6833) between brakeline and top of proportioning valve, and between brakeline and front of proportioning valve. See Fig 1 .
  5. Install Pressure Gauges (C-4007-A) on each adapter. See Fig 1 . Bleed air from pressure gauges. Bleed air from brakeline being tested at rear wheel cylinder.
  6. Have an assistant hold brake pedal down until inlet pressure at proportioning valve is 1000 psi (70 kg/cm2 ), and note outlet pressure on proportioning valve. Outlet pressure should be within specification. See PROPORTIONING VALVE OUTLET PRESSURE SPECIFICATIONS  table.
    PROPORTIONING VALVE OUTLET PRESSURE SPECIFICATIONS

    Model psi (kg/cm2 )
    Short Wheelbase
    AWD 525-640 (37-45)
    FWD 660-780 (46-55)
    Long Wheelbase
    AWD 690-800 (49-56)
    FWD 660-780 (46-55)
  7. Replace proportioning valve if outlet pressure is not within specification. If outlet pressure is within specification, go to next step.
  8. Remove test equipment. Reinstall brakelines on proportioning valve. Tighten brakeline nuts to specification. See TORQUE SPECIFICATIONS  table. Repeat test procedure on remaining rear brake hydraulic circuit. Replace proportioning valve if outlet pressure is not within specification.
    CAUTION: When installing proportioning valve, ensure proportioning valve-to-frame rail bolts are installed only in 2 front holes on mounting bracket for proportioning valve.
  9. Install and tighten proportioning valve-to-frame rail bolts to specification. Bleed brake system. See BLEEDING BRAKE SYSTEM  .
Fig 1: Testing Proportioning Valve (Models With ABS)
G96E25142Courtesy of CHRYSLER CORP.
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