GM Full Size Vans 1967-1986 Repair Guide

Shock Absorbers


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Fig. Fig. 1: View of a common rear shock absorber assembly and its retainers


The usual procedure for testing shock absorbers is to stand on the bumper at the end nearest the shock being tested and start the vehicle bouncing up and down. Step off; the vehicle should come to rest within one bounce cycle. The stiffness of the suspension on some models makes this rather difficult, unless you are a very "substantial'' individual. Another good test is to drive the vehicle over a bumpy road. Bouncing over bumps is normal, but the shock absorbers should stop the bouncing after the bump is passed, within one or two cycles.


See Figures 1, 2 and 3

The usual procedure is to replace shock absorbers in axle pairs, to provide equal damping. Heavy duty replacements are available for firmer control. Air adjustable shock absorbers can be used to maintain a level rid with heavy loads or when towing.

  1. Raise and support the van.
  3. Support the rear axle with a floor jack.
  5. If the van is equipped with air lift shocks, bleed the air from the lines and disconnect the line from the shock absorber.
  7. Disconnect the shock absorber at the top by removing the nuts, washer and bolt.
  9. Remove the nut, washer, and bolt from the bottom mount.
  11. Remove the shock from the van.

Before installation, purge the new shock of air by repeatedly extending it in its normal position and compressing it while inverted. It is normal for there to be more resistance to extension than to compression.

  1. Installation if the reverse of removal. If the van is equipped with air lift shock absorbers, inflate them to 10-15 psi minimum air pressure. Torque the shock absorber mounting nuts to 75 ft. lbs. (101 Nm).

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Fig. Fig. 2: Unfasten the top retaining bolt from the rear shock absorber ...

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Fig. Fig. 3: ... then remove the bottom nut, bolt and washer from the shock absorber mount