Piotr,

I am with your mechanics on this one. I have never had a shock "settle in" or some other terminology for changing the ride height in a few weeks. In every case I am familiar with the ride height was stable in a few tire rotations as the suspension went from hanging on the lift position to the normal supporting the car position.

The big deal about MB shocks is that they have a volume of trapped Nitrogen gas under high pressure with a sliding piston interface (with "O" ring seals) to separate it from the oil. The point of this feature is to keep the oil in the shock at a high enough pressure to avoid cavitation in the oil as it gets forced through the orifice that provides the damping. Once the shock oil gets warmed up from use, the typical, non-pressurized shock will cavitate, mixing the oil with little air/dissolved gas/oil vapor bubbles. This effectively changes the oil viscosity and other dynamic characteristics and the result is the shock performance will suffer.

In addition, the Nitrogen chamber adds a little length, and an additional spring rate, into the suspension system design. When this gas leaks out, and it will over time, ususally before the oil as Nitrogen is a linear molecule and it is much smaller than oil, or even water, so it leaks as the shock gets old, the shock height and added spring force goes away. The shock damping characteristics also change, but slowly as the gas leaks out so you don't notice it as readily. More of the car's mass is now supported by the coil springs and they collapse a little more, also over time so you don't notice it right off. I would suggest your rear shocks are shot as well, and if you replace them the car will ride at its design attitude and level. The real problem is likely that your old rear shocks are sagging, not your fronts being too tall.

Since most of the trunk load and rear seat load is borne by the rear suspension, if you have a car that is used a lot for hauling kids and junk in the trunk, you should see the rear shocks fail before the fronts.

Good luck, Jim

__________________
Own:
1986 Euro 190E 2.3-16 (291,000 miles),
1998 E300D TurboDiesel, 231,000 miles -purchased with 45,000,
1988 300E 5-speed 252,000 miles,
1983 240D 4-speed, purchased w/136,000, now with 222,000 miles.
2009 ML320CDI Bluetec, 89,000 miles

Owned:
1971 220D (250,000 miles plus, sold to father-in-law),
1975 240D (245,000 miles - died of body rot),
1991 350SD (176,560 miles, weakest Benz I have owned),
1999 C230 Sport (45,400 miles),
1982 240D (321,000 miles, put to sleep)