Removal & Installation
Before servicing the vehicle, refer to the Precautions Section.
NOTEDisconnecting the negative battery cable on some vehicles may interfere with the functions of the on-board computer systems and may require the computer to undergo a relearning process, once the negative battery cable is reconnected.
NOTEIf working near and/or around the SRS system and components, be sure to properly disable the SRS system. See disarming/arming the SRS system.
NOTEFor vehicles equipped with OnStar (RPO UE1), with battery backup, the backup battery is a redundant power supply to allow limited ONStar functionality in the event of a main battery power disruption to the OnStar module (VCIM). Do not disconnect the main vehicle battery or remove the OnStar fuse with the ignition key in any position other than OFF. Retained accessory power should be allowed to time out or be disabled by opening the driver-s side door before disconnecting power. Disconnecting power to the module in any way while the ignition is ON or with the retained accessory power activated may cause activation of the OnStar backup battery system and will discharge and permanently damage the backup battery. Once the backup battery is activated it will stay on until it has completely discharged. The backup battery is not rechargeable and once it is activated, it must be replaced.
- Disconnect the negative battery cable.
- Raise and support the vehicle safely.
- If equipped with ELC disconnect the required air lines.
Properly support the rear axle assembly, using a suitable jack.
CAUTIONBe sure that both the rear axle and frame are properly supported as personal injury or damage could result.
- Disconnect the lower shock retaining bolt.
- Disconnect the upper shock retaining bolts and nuts.
Remove the shock from the vehicle.
- Installation is the reverse of the removal procedure.
- Tighten the upper retaining bolts and nuts to 20 ft. lbs.
Tighten the lower retaining bolt and nut to 65 ft. lbs.
NOTEIf equipped with ELC do not put the weight of the vehicle on the shock until they have been inflated.
- Using the GM diagnostic scan tool or aftermarket equivalent reprogram the necessary systems and components. Be sure to follow the scan tool manufacturer-s directions.
The purpose of the shock absorber is simply to limit the motion of the spring during compression and rebound cycles. If the vehicle is not equipped with these motion dampers, the up and down motion would multiply until the vehicle was alternately trying to leap off the ground and to pound itself into the pavement.
Contrary to popular rumor, the shocks do not affect the ride height of the vehicle. This is controlled by other suspension components such as springs and tires. Worn shock absorbers can affect handling; if the front of the vehicle is rising or falling excessively, the -footprint- of the tires changes on the pavement and steering is affected.
The simplest test of the shock absorber is simply push down on one corner of the unladed vehicle and release it. Observe the motion of the body as it is released. In most cases, it will come up beyond it original rest position, dip back below it and settle quickly to rest. This shows that the damper is controlling the spring action. Any tendency to excessive pitch (up-and-down) motion or failure to return to rest within 2-3 cycles is a sign of poor function within the shock absorber. Oil-filled shocks may have a light film of oil around the seal, resulting from normal breathing and air exchange. This should NOT be taken as a sign of failure, but any sign of thick or running oil definitely indicates failure. Gas filled shocks may also show some film at the shaft; if the gas has leaked out, the shock will have almost no resistance to motion.
While each shock absorber can be replaced individually, it is recommended that they be changed as a pair (both front or both rear) to maintain equal response on both sides of the vehicle. Chances are quite good that if one has failed, its mate is weak also.