I just recently went through something like this. When ever I would turn the wheel I would get a creeking, groaning sound. Also when ever I got out of the car, I would here it as the body raised up. It turned out to be the driver's side balljoint. My mechanic said this is very common for the W116, and W126 cars. Particularly in the spring. He said during the winter the road salt and sand work their way into the joint and start grinding away. Since I had that replaced, the front end is silent again and my steering is a little tighter. As I learned, the balljoints are generally not a DIYer. At least for the W116/W126 cars, it requires a special tool to pull out and to press in the new balljoint into the spindle.
1994 MB E320 Coupe (199,500 mi)
1992 MB 190E 2.6 (173,000 mi)
1983 Porsche 911SC (148,000 mi)
2004 Volvo V70 2.5T (198,000 mi)
President of CT/Westchester Section