First, please turn your caps off. It's considered shouting, and makes it very difficult to read your posts.
On those axle assemblies, it's possible to get a bad reubuilt unit. I replaced the driver's side axle on the 190E 2.6 three times before getting a good unit. Luckily I bought from a good shop that took back the offending units.
I also changed the wheel bearings. Have you checked the rear suspension bushings as well? If you have play, they might contribute to the early demise of an axle.
1998 C230 "Black Betty"