There is only one small bolt which holds the rotor to the hub to keep rotor in place when removing caliper,this bolt is 6mm diameter and only needs to be snug.The two bolts holding the caliper on need to be cleaned and apply blue loctite and torque to 80 ft lbs. Its also a good idea to clean the rotor mounting area on the hub to remove any rust to insure a flat suface for rotor to mate to. Cleaning and repacking bearings would be advised at this mileage also.The bearings need to be readjusted to 0.01 to 0.02 mm end play.The best and most accurate way to adjust bearings is with a dial indiator setup.

__________________
Mercedes Benz Master Tech - Retired