If you face any mechanical issues with the rear wheel bearings - do not let the mechanic repair it by feel and purana tareeqa, There is a very intricate process to set them up. Even the front ones are very hard to get right to 0.02mm axial play. The old "nut mila dena" does not work with MB.
I recently redid the fronts on my W124 and took some pictures too, it requires a dial gauge to setup - trouble is that the camera is now MIA.