S&T Series Blazer, Bravada, Envoy, Jimmy, Rainier, Trailblazer, Xtreme

Rear Suspension

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Air Suspension



Depressurizing

CAUTION
A sudden release of pressure may cause personal injury or damage to the vehicle. The air suspension system is under pressure until the air supply lines are disconnected. Wear gloves, ear protection, and eye protection. Wrap a clean cloth around the air supply lines.

  1. Remove the air suspension system fuse.
  2.  
  3. Raise and support the vehicle.
  4.  
  5. Raise and support the rear axle at the designed height of 5.33 in. (135.4mm) on non-air suspension models or 6.12 in. (155.4mm) on air suspension models.
  6.  
  7. Remove the air compressor mounting bolts from the frame and support air compressor.
  8.  
  9. Loosen both of the air supply line connections at the air compressor in order to depressurize the air springs.
  10.  
  11. To pressurize the system, tighten the air supply lines to the air compressor to 20 inch lbs. (2.25 Nm).
  12.  
  13. Install the air compressor to frame mounting bolts and tighten to 15 ft. lbs. (20 Nm).
  14.  
  15. Lower the vehicle.
  16.  
  17. Install the air suspension system fuse.
  18.  
  19. Start the vehicle and run for approximately 1 minute to ensure that the air suspension system is functioning properly.
  20.  
  21. Check the axle height.
  22.  

Removal & Installation
  1. Depressurize the air suspension system.
    NOTE
    There is a raised feature on the outer rim of the air spring top plate that denotes the anti-rotation peg position.

  2.  
  3. Depress the anti-rotation peg (2) in the air spring top plate located in the upper spring seat.
  4.  
  5. With the anti rotation peg (2) depressed, rotate the air spring counterclockwise and remove the air spring from the upper spring seat.
  6.  
  7. Disconnect the air supply line from the air spring in the following way:
    1. Push the air supply line into the air spring connection and hold in place.
    2.  
    3. Depress and hold the air supply line collet down.
    4.  
    5. Remove the air supply line from the air spring.
    6.  

  8.  
  9. Remove the air spring.
  10.  

To install:

Click image to see an enlarged view

Fig. Locating anti-rotation peg in air spring



Click image to see an enlarged view

Fig. Air spring mounting

  1. Install the air supply line to the air spring. Ensure the air supply line is fully seated.
    CAUTION
    Ensure that the air spring is fully seated and properly positioned on the axle pilot. Failure to properly position the air spring may cause the air spring to break apart, possibly resulting in personal injury or damage to the vehicle.

  2.  
  3. Install the air spring (2) to the frame by aligning the mounting tabs (3) with the keyhole slots (1) in the upper spring seat.
  4.  
  5. Apply upward pressure to the air spring and rotate clockwise until the anti-rotation peg snaps into place.
  6.  
  7. Pressurize the system.
  8.  
  9. Lower the vehicle.
  10.  
  11. Install the air suspension system fuse.
  12.  
  13. Start the vehicle and run for approximately 1 minute to ensure that the air suspension system is functioning properly.
  14.  
  15. Check the axle height.
  16.  

Leaf Springs



Removal & Installation
2000-01 Vehicles
  1. Before servicing the vehicle, refer to the Precautions section.
    NOTE
    The following procedure requires the use of two sets of jackstands.

  2.  
  3. Support the rear axle with jackstands, support the axle and the body separately in order to relieve the load on the rear spring.
  4.  
  5. Remove or disconnect the following:

    Wheel
     
    Shock absorber
     
    U-bolt nuts, washers, anchor plate and bolts
     
    Spare tire, if equipped
     
    Rear exhaust hangers and lower the rear exhaust, if necessary
     
    Shackle-to-frame bolt, washers and nut
     
    Fuel tank, if necessary
     
    Front bracket nut, washers and bolt
     
    Spring
     
    Shackle from the spring, if necessary
     

  6.  

To install:

  1. Install or connect the following:

    Shackle to the rearward spring eye using the bolt, washers and nut, but do not fully tighten at this time
     
    Spring assembly
     
    Spring to the front bracket using the bolt, washers and nut, but do not fully tighten at this time
     
    Fuel tank, if removed
     
    Shackle-to-frame bolt, washers and nut, but do not fully tighten at this time. If used, remove the spring support.
     

  2.  
  3. Install the U-bolts, anchor plate, washers and U-bolt nuts. Torque the nuts using 2 passes of a diagonal sequence:
    1. Step 1: Torque to 18 ft. lbs. (25 Nm).
    2.  
    3. Step 2: Torque to 73 ft. lbs. (100 Nm) in sequence.

      Click image to see an enlarged view

      Fig. Typical rear suspension trim height measurement

    4.  

  4.  
  5. Position the axle to achieve an approximate gap of 6.46-6.94 in. (164-176mm) between the axle housing tube and the metal surface of the rubber frame bumper bracket. Measure from the housing between the U-bolts to the metal part of the rubber bump stop on the frame.
  6.  
  7. While supporting the axle in this position, tighten the front and rear spring mounting fasteners to 89 ft. lbs. (122 Nm).
  8.  
  9. Install or connect the following:

    Rear exhaust in position and tighten the hangers
     
    Spare tire
     
    Shock absorber
     

  10.  

Shock Absorbers



Removal & Installation
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Properly support the rear axle assembly.
  4.  
  5. Remove or disconnect the following:

    Automatic level control air lines from the shock absorber, if equipped
     
    Shock absorber-to-frame retainer(s) at the top of the shock
     
    Shock-to-axle retainer(s) at the bottom of the shock
     
    Shock absorber
     

  6.  

To install:

  1. Install the shock in the vehicle and loosely install the upper mounting fasteners to retain it
  2.  
  3. Align the lower-end of the shock absorber with the axle mounting, then loosely install the retainers.
  4.  
  5. On 2001 models, tighten the upper shock retainers to 18 ft. lbs. (25 Nm). Tighten the lower shock retainers to 62 ft. lbs. (84 Nm) on two door models and 74 ft. lbs. (100 Nm) on four door models.
  6.  
  7. On 2002 models, tighten the upper and lower shock retainers to 59 ft. lbs. (80 Nm).
  8.  
  9. If equipped, attach the automatic level control air lines to the shock absorber.

    Click image to see an enlarged view

    Fig. Rear shock absorber mounting

  10.  

Sway Bar



Removal & Installation
2002-05 Vehicles
  1. Raise and support the vehicle.
  2.  
  3. Remove the stabilizer shaft links to the stabilizer shaft retaining nuts.
  4.  
  5. Remove the stabilizer shaft insulator clamp mounting bolts.
  6.  
  7. Remove the stabilizer shaft insulator clamp from the stabilizer shaft insulator.
  8.  
  9. Remove the stabilizer shaft insulators from the stabilizer shaft.
  10.  
  11. Remove the stabilizer shaft from the vehicle.
  12.  

To install:

  1. Install the stabilizer shaft to the vehicle.
  2.  
  3. Install the stabilizer shaft insulators to the stabilizer shaft.
  4.  
  5. Install the stabilizer shaft insulator clamp to the stabilizer shaft insulator.
  6.  
  7. Install the stabilizer shaft insulator clamp mounting bolts and tighten to 52 ft. lbs. (70 Nm).
  8.  
  9. Install the stabilizer shaft links to the stabilizer shaft and tighten to 74 ft. lbs. (100 Nm).
  10.  
  11. Lower the vehicle.
  12.  

Upper Control Arms



Removal & Installation
  1. Raise and support the vehicle.
  2.  
  3. Remove the wheel and tire.
  4.  
  5. Raise and support the rear axle at the designed height of 5.33 in. (135.4mm) on non-air suspension models or 6.12 in. (155.4mm) on air suspension models.
  6.  
  7. If equipped with air suspension, depressurize the air suspension system.
  8.  
  9. Remove the rear axle lower control arm to the axle mounting nut and bolt.
  10.  
  11. Remove the rear axle lower control arm to the frame mounting nut and bolt.
  12.  
  13. Remove the lower control arm.
  14.  

To install:

  1. Install the lower control arm.
  2.  
  3. Install the rear axle lower control arm to the frame mounting nut and bolt.
  4.  
  5. Install the rear axle lower control arm to the axle mounting bolt and nut and tighten to 74 ft. lbs. (100 Nm).
  6.  
  7. Remove the rear axle support.
  8.  
  9. Lower the vehicle.
  10.  

2002-05 Vehicles
  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Raise and support the vehicle.
  4.  
  5. Support the rear axle.
  6.  
  7. Remove the shock absorber lower mounting bolts.
    NOTE
    Do not lower the rear axle so the upper control arms contact the frame. This will damage the upper control arms.

  8.  
  9. Lower the rear axle, then remove the coil springs.
    NOTE
    Be careful not to chip or scratch the coating of the coil springs when removing and installing the springs. Damaging the coating will cause premature failure of the coil springs.

  10.  

To install:

  1. Install the coil springs, then raise the rear axle.
  2.  
  3. Install the shock absorber lower mounting bolts and tighten to 59 ft. lbs. (80 Nm).
  4.  
  5. Remove the rear axle support.
  6.  
  7. Lower the vehicle.
  8.  

Wheel Bearings



Adjustment

The wheel bearings on these vehicles are not adjustable. If the bearings become loose or make noise, they must be replaced.

Removal & Installation

A new pinion shaft lockbolt should be installed whenever either of the axle shafts is removed.

The axle shaft and seal may be removed and replaced without disturbing the bearing or seal but it is highly recommended to replace the seals when removing the axle shaft.

  1. Before servicing the vehicle, refer to the Precautions section.
  2.  
  3. Remove or disconnect the following:

    Rear wheels
     
    Brake drums

    Click image to see an enlarged view

    Fig. Pinion shaft lockbolt and axle C-lock locations, inside the differential

     

  4.  
  5. Using a wire brush, clean the dirt/rust from around the rear axle cover.
  6.  
  7. Drain the fluid.
  8.  
  9. Remove or disconnect the following:
    NOTE
    Be careful not to damage the oil seal.


    WARNING
    If equipped with an Anti-Lock Brake System (ABS), be careful not to damage the reflector ring on the axle shaft or the speed sensor bolted to the backing plate, immediately adjacent to the shaft.



    Rear pinion shaft lockbolt and the pinion shaft
     
    C-lock from the button end of the axle shaft by pushing the axle shaft inward
     
    Axle shaft from the axle housing
     

  10.  
  11. Remove or disconnect the following:
    WARNING
    DO NOT damage the housing oil seal surface.



    Oil seal by prying the it from the end of the rear axle housing
     



    Wheel bearing using the GM Slide Hammer tool J-2619, the GM Adapter tool J-2619-4 and the GM Axle Bearing Puller tool J-22813-01

    Click image to see an enlarged view

    Fig. Cross-sectional view of the rear axle, bearing and seal assembly

     

  12.  

To install:

  1. Clean and inspect the components for excessive wear or damage and replace them, if necessary.
  2.  
  3. Install or connect the following:
    WARNING
    Be sure the bearing installer does not contact and damage the speed sensor on ABS equipped vehicles.


    NOTE
    Be sure the seal installer does not contact and damage the speed sensor on ABS equipped vehicles.


    WARNING
    BE CAREFUL not to damage the wheel bearing seal.



    New or reused bearing, coated with gear lubricant, using the Axle Shaft Bearing Installer tool J-34974 to drive the bearing in until it bottoms against the seat
     



    New seal lubricated with gear oil using the GM Axle Shaft Seal Installer tool J-33782 to seat it in the housing until it is flush with the axle tube
     



    Axle shaft into the housing by engaging the splines
     
    C-lock retainer on the axle shaft button end
     



    Axle shaft by pulling it outward to seat the C-lock retainer in the counterbore of the side gears
     
    Pinion shaft through the case and the pinions. Tighten the new lockbolt to 27 ft. lbs. (36 Nm).
     
    New rear axle cover gasket
     
    Housing cover
     
    Brake drums
     
    Wheels
     

  4.  
  5. Refill the housing.
  6.  

 
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