First time posting for tech help, but this one has me (and my MB mechanic) stumped.

I have a 1990 560SEL with 85K miles, which was purchased from a family friend. When I bought the car, it had blown accumulators and was sagging to one side.

Since then we've replaced:

- Accumulators
- rear coil springs
- rear struts (which, for self-levelling suspension models, are ludicrously expensive).

The car looked and drove great. But within a few hundred miles, the rear started to ride really high. I had my mechanic look at it, and he adjusted the self-levelling controller arm to its shortest length, which brought the height of the car back to normal. So far so good.

Since then (this is about 2 months ago), I've had the car parked for most of the time, and driven it to dinner two or three times. But this week, I noticed that again, the rear end is really, really high.

I brought it back to my mechanic, and adjustment of the self-levelling controller arm doesn't adjust the height of the car in any way. What??

Let me know if you have any ideas...