I do not like the adjustment-thing....I had bad experiences with Mercedes parts: when you adjust it to hard, the stearingbox will break down -> lot`s of wear in the middle position, then you adjust it, but the wear at the left and right side is not so heavy and when you turn to the right or left, it can stick or at least break the inner part.First things first: Did you try to tighten up the adjusting knob on top of the box? Easy to do.