Mercedes Benz repair: 1987 300E rear wheel problem, rear wheel bearings, mercedes dealer

Question
I keep having a problem with the right rear wheel. It started sounding like a VERY bad bearing problem, the noise is very loud. The mechanic told me the axle nut was loose. He tightened it and it was fine for about a week, then it started again. He tightened it again and it was fine for about another week. He told be the axle nut might be bad. I bought a new one and it lasted about a month before the noise came back. 2 weeks ago they put lock tite on it. Not only is the noise back again, but the tire is shot. It only has about 10K on it and it is completely worn. What can I do to have this problem fixed for good?! Thanx

Answer
STOP driving the vehicle, and find another mechanic.
The bearing is set with final torque preload sleeve, tightening the nut wrecks the preload sleeve.

Replace the right rear wheel bearings and preload sleeve, they are bad.
Only a Mercedes dealer and some Mercedes specialty shops will have the correct tools for this job.

Danger:
Death or vehicle Damage can result from incorrect repair.
Continued driving without repair will result in more mechanical damage, and possible death or injury.