GM Full Size Vans 1987-1997 Repair Guide

Shock Absorbers

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REMOVAL & INSTALLATION



See Figures 1, 2, 3, 4 and 5



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Fig. Fig. 1: Front shock absorber mounting points - G models



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Fig. Fig. 2: Front shock absorber mounting points - P models

  1. Raise and support the front end on jackstands.
  2.  
  3. Hold the shock absorber stem with a wrench, then remove the upper end nut and washer.
  4.  
  5. Remove the lower end nut, bolt and washer.
  6.  
  7. Remove the shock absorber and inspect the rubber bushings. If these are defective, replace the shock absorber assembly.
  8.  



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Fig. Fig. 3: Loosen the front shock absorber lower mounting bolts



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Fig. Fig. 4: Hold the shock absorber stem with a wrench and loosen the upper nut

To install:
  1. Fully extend the shock absorber, insert it through the coil spring and control arm, then loosely install the retainers.
  2.  
  3. When installing the shock, tighten the upper end nut to 80 ft. lbs. (108 Nm) on 1987-95 models; and 12 ft. lbs. (16 Nm) on 1996-97 models. Tighten the lower end bolt to 74 ft. lbs. (101 Nm) on 1987-95 models; and 24 ft. lbs. (33 Nm) on 1996-97 models.
  4.  

TESTING



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.

Countrary 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 unladen 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.



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Fig. Fig. 5: When fluid is seeping out of the shock absorber, it-s time to replace it

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.

 
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