Removal & Installation
- Before servicing the vehicle, refer to the Precautions section.
- Turn the air suspension switch to the OFF position.
Remove or disconnect the following:
Negative battery cable
- If replacing the shock absorbers, transfer the mass dampers and mounting brackets.
Turn the shock absorber upside down. Compress and expand the piston several times to remove the air from the working cylinder.
Install or connect the following:
Shock absorber assemblies. Tighten the upper bolts to 25-34 ft. lbs. (34-46 Nm), and the lower bolts to 58-68 ft. lbs. (68-92 Nm).
- Turn the air suspension system ON .
- Make sure the ignition switch is in the OFF position.
- Disconnect the height sensor connector link before allowing the rear axle to hang free.
- Raise and safely support the vehicle so the suspension arms hang free. The rear shock absorbers will vent air through the compressor and a hissing noise will be heard. When the noise stops, the air lines can be disconnected. A residual pressure of 8-24 psi will remain in the air lines.
- Disconnect the air line by pushing in on the retainer ring(s) and pulling the line(s) out.
- Remove the top retaining nut, washer, and bushing.
- Remove the bottom retaining nut and washer. Remove the shock absorber.
- Position the shock absorber and install the bottom retaining washer and nut. Tighten to 52-85 ft. lbs. (70-115 Nm).
- Install the top bushing, washer, and retaining nut. Tighten to 14-26 ft. lbs. (19-35 Nm).
- Connect the air line to the shock absorber by pushing in on the retainer ring and installing the air line.
- Connect the height sensor connecting link and lower the vehicle.
- If equipped with air suspension, turn the air suspension switch OFF .
- Raise and safely support the vehicle. Make sure the rear axle is supported.
- To assist in removing the upper attachment on shock absorbers using a plastic dust tube, place and open end wrench onto the hex stamped into the metal cap of the dust tube. For shock absorbers with a steel dust tube, simply grasp the tube to prevent stud rotation when loosening the retaining nut.
- Remove the shock absorber retaining nut, washer, and insulator from the stud on the upper side of the frame. Discard the nut. Compress the shock to clear the hole in the frame and remove the inner insulator and washer from the upper retaining stud.
- Remove the self-locking retaining nut and disconnect the shock absorber lower stud from the mounting bracket on the rear axle.
Prime the new shock absorber as follows:
- With the shock absorber right side up (as installed in the vehicle), extend it fully.
- Turn the shock upside down and fully compress it.
- Repeat the previous 2 steps at least 3 times to make sure any trapped air has been expelled.
- Place the inner washer and insulator on the upper retaining stud and position the shock absorber with the stud through the hole in the frame.
- While holding the shock absorber in position, install the outer insulator, washer, and a new stud nut on the upper side of the frame. Tighten the nut to 25 ft. lbs. (34 Nm).
- Extend the shock absorber and place the lower stud in the mounting bracket hole on the rear axle housing. Install a new self-locking nut and tighten to 56-76 ft. lbs. (77-103 Nm).
- Lower the vehicle and, if equipped, turn the air suspension switch ON .
Testing & Inspection
Except Air Shock Absorbers
- Remove the shock absorber from the vehicle.
- Extend the shock absorber fully while it is right side up, as installed in the vehicle. Then turn it upside down and fully compress it. Repeat this procedure at least 3 times to make sure any trapped air has been expelled.
- Place the shock absorber right side up in a vise and hand stroke the shock absorber. Check the shock absorber insulators for damage and wear.
- If the shock absorber is properly primed, in its installed position, and there is a lag or a skip occurring near mid-stroke of the shaft reverse travel direction, the shock absorber must be replaced.
- Replace the shock absorber if there is any seizing during the shaft full travel, except at either end of the travel.
- Replace the shock absorber if upon the shaft fast, reverse stroke, there is any noise encountered other than a faint swish, such as a clicking sound.
- If there are excessive fluid leaks, and the shock absorber action remains erratic after purging air, replace the shock absorber.