Struts or Shock Absorbers Bench Test Non-Spiral Groove-Pliacell

It is not necessary to purge air from non-spiral groove shock absorbers. These shock absorbers contain a gas filled cell within the shocks reservoir. These shocks differ from spiral groove shocks. Spiral groove shocks contain an air filled cell within the reservoir.

1. Remove the shock absorber from the vehicle. Refer to Shock Absorber Replacement in Front Suspension.

Important: Do not clamp the vise jaws on the shock upper stem threads or the reservoir.

2. Place the shock absorber in a vise.

•	Clamp the jaws on the top mounting stud of the shock.

•	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.

•	The rebound force normally is stronger than the compression force (approximately two to one).

•	The rebound force should be smooth and constant for each stroke rate.

4. Compare this shock with a good shock absorber.
5. If you observe any of the following conditions, replace the shock absorber:

•	A skip, or a lag, at reversal near mid-stroke

•	A seizing (except at the extreme ends of travel)

•	A noise, a grunt or a squeal, after completing one full stroke in both directions

•	A clicking noise at fast reversal