Envoy 4WD V6-4.3L VIN W (1998)
Suspension Strut / Shock Absorber: Testing and Inspection
TESTING PROCEDURE
It is not necessary to purge air from nonspiral groove shock absorbers. These shock absorbers contain a gas-filled cell within the absorbers reservoir.
These shocks differ from spiral groove shock absorbers. Spiral groove shocks contain an air-filled cell within the reservoir.
1. Remove the shock absorber from the vehicle.
Important: Do not clamp the vise jaws on the shock upper stem threads or the reservoir.
2. Place the shock absorber in a vise.
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Clamp the vise jaws on the top mounting stud of the shock.
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Hold the shock vertically in the vise with the bottom end up.
3. Pump the shock at various rates of speed. Observe the rebound force.
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The rebound force normally is stronger than the compression force (approximately two to one).
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The rebound force should be smooth and constant for each stroke rate.
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Compare this shock with a good shock absorber.
5. If you observe any of the following conditions, replace the shock absorber:
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A skip, or a lag, at reversal near midstroke
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A seizing [except at the extreme ends of travel)
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A noise, a grunt or a squeal, after completing one full stroke in both directions
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A clicking noise at fast reversal
