Hi. Not entirely clear to me. Can you describe how you are trying to "adjust" the suspension?
There is an adjustment linkage that sets the ride height in the back, lengthening it or shortening it makes the rear go up and down via a valving arrangement. Is that what you're adjusting?
If so, nothing is happening????
Is the hydraulic fluid circulating through the system OK? If you remove the return line from the top of the tank under the hood while the car is running, the flow should be pretty steady. Mine will empty the tank in about a minute unless its connected.
If the hydraulics seem in good order and the leveling valve is unresponsive, I suspect the valve is bad... but before you replace, I'd have the pressures checked.