GM Service Manual Online
For 1990-2009 cars only

    Notice: Do not clamp the vise jaws on the shock absorber reservoir tube or shaft. Doing so could damage component.

  1. Place the shock absorber in a vertical position (top end up). Clamp the bottom mount in a vise.
  2. Rotate the dust tube. Notice if any binding condition exists. Compare the action with a known good shock, if necessary. A binding condition indicates a scored rod. Replace shocks with scored pistons.
  3. Fully extend the shocks and examine the shocks for leaks in the seal cover area. Shock fluid is a very thin hydraulic fluid and has a characteristic odor and dark brown tint. A slight trace of shock fluid around the seal cover area is not cause for shock replacement. The shock seal is made to permit a very slight seepage in order to lubricate the rod. Replace leaky units.
  4. Inspect the shock for dents. A bent rod could cause the shock to bind.
  5. Extend and compress each shock in order to determine that the shock has control (resistance) in both jounce and rebound.
  6. Visually inspect the shock mounting for the following:
  7. • Broken mounts
    • Extreme bushing wear
    • A shifted bushing or wear
    • Deep cracks in the bushing material, shallow surface cracks are normal.