Power Steering System: Adjustments Chevrolet Silverado 3500

Thrust Bearing Preload Adjustment

Note. Refer to Fastener Notice in Cautions and Notices.

Scheme 10

Scheme 11

Scheme 12

Scheme 13

1. Turn the adjuster nut assembly clockwise using J 42882 until the adjuster nut assembly and the thrust bearing support are firmly bottomed in the steering gear housing. Tighten: Adjust the adjuster nut assembly to 29.5 N.m (22 lb ft).
2. Place an index mark (1) on the steering gear housing even with one of the holes (2) in the adjuster nut assembly.
3. Measure back counterclockwise 13 mm (.5 inch).
4. Place a second mark on the steering gear housing.
5. Using J 42882 and a torque wrench, turn adjuster nut assembly counterclockwise 22-32 degrees to align the hole in the adjuster nut assembly with the second mark on the steering gear housing.
6. Install the lock nut.
7. Hold the adjuster nut assembly in position to maintain alignment of the marks.
8. Tighten the lock nut using J 42882 , J 43435 and a torque wrench. Tighten: Tighten the lock nut to 109 N.m (80 lb ft).
9. Adjust the pitman shaft over center preload. Refer to «Pitman Shaft Over-Center Preload Adjustment - Off Vehicle»(ref-184156-S12670584002005082200000) .

Scheme 14

Scheme 15

Scheme 16

1. Loosen the lash adjuster lock nut.
2. Turn the pitman shaft adjuster screw counterclockwise until fully extended.
3. Turn the pitman shaft adjuster screw clockwise 1 full turn.
4. Rotate the stub shaft from stop to stop, using 12-point socket while counting the number of turns.
5. Starting at either stop, turn the stub shaft back half the total number of turns. This is the CENTER of the gear.
6. Make sure the gear is centered by checking the following items: The flat on the stub shaft (2) faces upward. The flat on the stub shaft is parallel with the side cover. The master spline (3) on the pitman shaft is in line with the adjuster screw (1).
7. Place a torque wrench on the stub shaft with the handle in the vertical position.
8. Rotate the stub shaft 45 degrees from each side of the center of the stub shaft. The stub shaft must rotate smoothly and must not stick or bind.
9. Record the worm bearing preload measured on or near the center.
10. Recorded bearing preload must be 0.7-1.7 N.m (6-15 lb in), with the worm and the ball nut installed. If the torque is outside this range, readjust or repair the steering gear assembly as required.
11. To obtain the correct preload torque, adjust the over center torque by turning the pitman shaft adjuster screw clockwise.
12. Add 0.7-1.1 N.m (6-10 lb in) torque to the previously measured worm bearing preload torque. NOTE: Refer to «Fastener Notice»(ref-184123-S11449185592005082200000) in Cautions and Notices. Tighten: Tighten the lash adjuster lock nut to 49 N.m (36 lb ft). Prevent the adjuster screw from turning while tightening the lash adjuster lock nut. Install the steering gear into the vehicle. Refer to «Power Steering Gear Replacement (Rack and Pinion)»(ref-184156-S28862291522005082200000) or «Power Steering Gear Replacement (Non Rack and Pinion)»(ref-184156-S34368569742005082200000) . Bleed the power steering system. Refer to «Bleeding the Power Steering System»(ref-184156-S36358444172005082200000) .

Scheme 17

1. Remove the nut (3).
2. Remove the lock washer (2).
3. Clean the exposed end of the pitman shaft.
4. Clean the steering gear housing (1).
5. Use a wire brush to clean the pitman shaft splines.
6. To center the stub shaft: Rotate the stub shaft (1) with a wrench from stop to stop. Count the number of turns. Rotate the stub shaft back 1/2 of the total amount of turns.
7. Remove the pitman shaft cover bolts (1) from the pitman shaft and cover assembly (3). Remove the lash adjuster nut (2) from the pitman shaft and cover assembly (3).
8. Remove the pitman shaft and cover assembly (3).
9. Remove the pitman shaft cover O-ring (4) from the steering gear housing assembly.

Scheme 18

1. Install the new pitman shaft cover O-ring (4).
2. Install the pitman shaft and cover assembly (3) onto the steering gear housing assembly.
3. Install the lash adjuster nut (2) onto the pitman shaft and cover assembly (3)
4. Install the pitman shaft cover bolts (1) onto the pitman shaft and cover assembly (3). Tighten: Tighten the pitman shaft cover bolts to 62 N.m (46 lb ft).
5. Install the lock washer (2).
6. Install the nut (3).
7. If necessary adjust the pitman shaft. Refer to «Pitman Shaft Over-Center Preload Adjustment - Off Vehicle»(ref-184156-S12670584002005082200000) .

Scheme 19

Scheme 20

1. Remove the nut (3).
2. Remove the lock washer (2).
3. Clean the exposed end of the pitman shaft.
4. Clean the steering gear housing (1).
5. Use a wire brush to clean the pitman shaft splines.
6. Loosen the adjuster lock nut (1).
7. Remove the bolts (2).
8. Remove the nut.
9. Rotate the stub shaft (6) using a 12-point socket to center the steering gear (7).
10. Remove the following items as an assembly: The side cover (8) The gasket (3) The pitman shaft (4)
11. Remove the pitman shaft (4) from the side cover (8).

Calibration Criteria

The brake pedal position (BPP) sensor receives a low reference signal and a 5-volt reference signal from the electro-hydraulic power steering (EHPS). Whenever the brake pedal is applied, the brake pedal position sensor applies a variable voltage signal to the EHPS through the BPP sensor signal circuit. Brake pedal position sensor calibration must be performed after the brake pedal position sensor or EHPS system have been serviced. The calibration procedure will set brake pedal position sensor home value. This value is used by the EHPS to determine the brake pedal position and the brake pedal rate. These two outputs are provided to the hybrid control module (HCM) via GMLAN.

Calibration Procedure

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. Navigate to the Special Functions screen on the scan tool and select BPP Sensor Calibration in order to perform the brake pedal position sensor calibration.