Mercedes, drive belt tensioner replacement in Hevel Eilot

Mercedes, drive belt tensioner replacement in Hevel Eilot.
The following signs indicate the need to replace the drive belt tensioner: the presence of traces of rust between the lever and the base, a worn pulley bearing, a worn pulley, misalignment of the block and tensioner lever, noise in the tensioner, jamming during movement of the tensioner lever, relaxing of spring. Replacing the drive element or alternator tensioner begins with disconnecting the battery and securing the crankshaft. After that, it is required to remove the fastener, which is responsible for the tension force, thereby weakening the alternator belt. Then the belt and tensioner roller are removed, defective elements are replaced and new ones are installed.