Bench Checks
AIR-ADJUSTABLE (ELC) STRUT DAMPERAll air-adjustable strut dampers should be stroked before attempting a bench check. When stored horizontally, such as new units in stock, an air pocket may develop in the pressure chamber. This pocket can also form when an air adjustable strut is off the vehicle if it is not continuously held with the top end up.
Perform the following procedure to remove air from the pressure chamber:
^ Extend in vertical position, top end up.
^ Collapse in vertical position top end down.
^ Repeat this procedure five (5) times to make sure air is purged from the pressure chamber.
1. Clamp the strut in a vise with the strut damper upright, top end up. Do not clamp on the reservoir tube.
2. Pump strut damper by hand at various rates of speed and note the resistance.
3. Rebound resistance normally is stronger than compression resistance by about 2 to 1. The resistance should be smooth and constant for each stroking rate.
4. Compare with a strut damper known to be good.
5. It is normal to hear a hissing noise. The following symptoms are abnormal and are reason for replacement.
a. A skip or lag at reversal near mid-stroke.
b. A seize (except at either extreme end of travel).
c. A noise (such as a grunt or squeal) after completing one full stroke in both directions.
d. A clicking noise at fast reversal.
e. Fluid leakage.
FRONT STRUT DAMPER
The bench check for front strut dampers is the same as that given for the rear air-adjustable dampers.