Just to clarify, I assume you mean that its level when the car is running and sags when the engine is turned off.

Also what part are you referring to as the actuator?


If it goes to level on both sides when you start it, then there must be a leak on the sagging side.

There is only one line out from the SLS valve. It runs to a T-fitting which splits off to the actuators (hydraulic rams or "shocks"). EDIT, see post 5

Your leak must be between that T-fitting and the accumulator on the right side. That includes the line to the actuator, the actuator itself, the line to the accumulator and accumulator itself.

Now that I've said that, I'm wondering if there could be air in the actuator.

If so, its supposed to be a self bleeding system, and repeated manual operation of the valve lever should burp it.