"and it's the movement of the membrane that provides the "shock absorption". But, fluid dampening occurs inside the strut similar to any other "shock". "


A rather good description overall except for the above statement. The accumulator does NOT act as a dampener (theoretically - I'm sure some dampening has to take place do to flow friction). Its job is too act as a hydraulic spring.

If the car was straight lifted by struts on hydraulic pressure the thing would have no suspension (fluid not being compressible). The added lifting capability is gained through adjustable hydraulic springs achieved through the accumulators.

I would replace them, they are always bad. My recommendation is to replace them every 100k miles as the system takes a huge beating as it becomes straight hydraulic struts without the effect of accumulators. They don't fail like light switches. They loose capacity to recieve a bump and it slowly becomes evident.

If, as is so common, they are driven well past the stage of no spring left, they become rigid. Sometime after this the rigidity drives the fluid from the system back into the reservoir. I am not sure exactly what happens to maintain this as the car now is not supported and feels as if there are no shock in the rear (bounces like a basketball). I don't understand what is happening there since if one replaces the accumulators most systems restore themselves.

__________________
Steve Brotherton
Continental Imports
Gainesville FL
Bosch Master, ASE Master, L1
33 years MB technician