How to Replace the Alternator in a Mercedes Benz

by Alibaster Smith

The alternator for the Mercedes Benz is responsible for powering all of the electrical devices in the car. It is designed to last for at least 60,000 miles. When the alternator dies, the first sign is the battery light illuminating on the dash. When the battery light illuminates, it is, ironically, usually not just the battery. Since the alternator charges the battery, when the alternator dies, the battery starts to draw down to feed the electrical components. This draw, in turn, kills the battery.

Step 1

Examine the drive belt configuration. The Mercedes Benz line of vehicles uses a serpentine belt (one long belt) to power the alternator and a series of other electrical components. Note the orientation of the belt. There is a belt diagram on the underside of the hood and on the frame of the Benz next to the hood latch (on some models).

Step 2

Release tension on the alternator belt. Turn the center tension pulley clockwise with a socket wrench. This will create slack in the belt.

Step 3

Slide the belt off the alternator. You will need to remove the belt from all of the other components on the system as well.

Step 4

Remove the electrical connector on the back of the alternator.

Step 5

Remove the top and bottom alternator mounting bolts and slide the alternator out of the engine bay.

Step 6

Install the new alternator. Installation is the reverse of the removal process. When installing the belt, it is best to use a new one. They're relatively inexpensive for the Benz and by the time an alternator needs to be replaced, the belt is usually worn to the point where it will likely need to be replaced soon as well. Make sure that the belt sits directly in the center of the pulley, and that the teeth on the belt sit in the pulley's grooves. Route the belt according to the belt path on the underside of the hood.

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