REMOVAL & INSTALLATION
Without Automatic Leveling
See Figures 1 through 5
- 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 nut on shock absorbers using a plastic dust tube, place an open end wrench on the hex stamped into the dust tube's cap. 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.
To remove any air from the shock which could effect overall performance proceed 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 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 .
See Figures 6, 7 and 8
- 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 (55-165 kPa) 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).
Check the rubber sleeve on the shock absorber to be sure it is not wrapped up. To assist in identifying wrap-up during installation, a white stripe is on the rubber sleeve and on the shock absorber body. The stripes should align. To correct a wrap-up condition, loosen the upper shock retaining nut and turn the shock to align the stripes. Retighten the retaining nut.
- 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.
Each shock absorber can be tested by bouncing the corner of the vehicle until maximum up and down movement is obtained. Let go of the vehicle. It should stop bouncing in 1-2 bounces. If not, the shock absorber should be inspected for damage and possibly replaced.Shock Absorber Mounting
Check the shock absorber mountings for worn or defective grommets, loose mounting nuts, interference or missing bump stops. If no apparent defects are noted, continue testing.Fluid Leaks
Disconnect each shock absorber lower mount and pull down on the unit until it is fully extended. Inspect for leaks in the seal area. Shock absorber fluid is very thin and has a characteristic odor and dark brown color. Do not confuse the glossy paint on some shock absorbers with leaking fluid. A slight trace of fluid is a normal condition; shock absorbers are designed to seep a certain amount of fluid past the seals for lubrication. If you are in doubt as to whether the fluid is coming from the shock absorber itself or from some other source, wipe the seal area clean and manually operate the shock absorber, using the following procedure. Fluid will appear if the unit is leaking.
It may be necessary to fabricate a holding fixture for certain types of shock absorbers.
- Grip the lower end of the shock absorber. Pull down (rebound stroke) and then push up (compression stroke). Compare the rebound resistance of both shock absorbers and compare the compression resistance. Usually, any shock absorber showing a noticeable difference will be the one at fault.
- If the shock absorber has internal noises, extend it fully, then exert an extra pull. If a small additional movement is felt, this usually means a loose piston, and the shock absorber should be replaced. Other noises which indicate the need for replacement are a squeal after a full stroke in both directions, a clicking noise on fast reverse, and a lag at reversal near mid-stroke.