Height Sensing Proportioning Valve - Adjustment

87chrysler5

Models


"N" Body Cab/ Chassis or Vehicles Equipped With Special Equipment Bodies


Subject


Rear Brake Height Sensing Proportioning Valve Adjustment


Index


BRAKES


Date


September 14, 1987

No.


05-01-87 (C1-05)

P-3227
THIS BULLETIN APPLIES ONLY TO DAKOTA VEHICLES SOLD AS CAB AND CHASSIS MODELS AND/OR EQUIPPED WITH SPECIAL BODIES INSTALLED BY AFTERMARKET INSTALLERS.

"N" body trucks use a height sensing control valve in the brake system that varies hydraulic pressure to the rear brakes according to the load. When these vehicles are equipped with a special equipment body, the curb weight and the frame height of the vehicle will vary, necessitating a different adjustment procedure for the height sensing control valve.

Use the following procedure to adjust the height sensing control valve on vehicles equipped with special bodies prior to customer delivery.

NOTE: THE VEHICLE MUST BE SITTING ON ALL FOUR WHEELS OR SUPPORTED BY THE REAR AXLE TO PERFORM THE FOLLOWING ADJUSTMENT.

1. Measure and record the distance from the top of the rear axle housing tube to the bottom of the left frame rail (beside the jounce jumper).

2. Add load to the vehicle or lift the rear of the vehicle as required, to obtain an axle tube-to-bottom side frame rail dimension of 6-3/4" plus or minus 1/8".

3. Refer to the 1987 Dakota Service Manual ("HYDRAULIC SYSTEM CONTROL VALVES", page 5-20 - Height Sensing Proportioning Valve Adjustment). DISREGARD STEP 1 OF THE ADJUSTMENT PROCEDURE IN THE SERVICE MANUAL. THE VEHICLE MUST BE SITTING ON ALL FOUR WHEELS.
Continue with Steps 2 through 5 of the service manual adjustment procedure to complete the adjustment of the height sensing proportioning valve actuator.

NOTE: THIS ADJUSTMENT PROCEDURE, WITH A CONTROLLED AXLE TO FRAME HEIGHT, MAY BE USED ON VEHICLES EQUIPPED WITH A SPECIAL EQUIPMENT BODY ANY TIME THE HSPV SYSTEM HAS BEEN DISTURBED THROUGH PARTS REMOVAL OR REPLACEMENT. AS NOTED IN THE OWNER'S MANUAL, NO AUXILIARY SUSPENSION DEVICES MAY BE ADDED TO THE REAR SUSPENSION, AND THE VEHICLE MUST BE EQUIPPED WITH THE ORIGINAL BUILD SPRINGS, OR EQUIVALENT MOPAR REPLACEMENT SPRINGS.


POLICY: Information only