I'm pretty sure that my SLS/hydropneumatic suspension pump is working OK. When I was under there adjusting the level, I moved the actuator arm while the engine was idling (600-750 rpm). The car moved both up and down rather briskly.

Those are simple radial piston pumps that are lubricated by the engine and hydraulic fluid. 'Wearing out' is possible if the system was run completely out of fluid or if the fluid is contaminated and has damaged the pump.

Another cause of slow lifts may be a clogged actuating valve or pinched/damaged hydraulic supply line that isn't admitting enough fluid to the cylinders.

Do you have the FSM for the 123 chassis? If not, let me know and I'll scan the appropriate pages for you.

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Never a dull moment at Berry Hill Farm.