How to Adjust an Alternator Bolt in a 1982 Mercedes Benz 240D

1. Open the hood on the 240D. Locate the alternator on the passenger side of the engine. Loosen the upper nut on the rear of the alternator with a ratchet and socket. If you cannot fit a ratchet and socket into the space, use an open-end wrench. Loosen the bolt directly below the nut. Loosen the bottom bolt on the outer passenger side of the alternator.
2. Rotate the tensioner nut directly above the alternator. This nut faces upward slightly and toward the passenger side. Turn the tensioner one-quarter turn at a time until the alternator belt is tightened.
3. Tighten the two bolts and the nut on the rear of the alternator using a ratchet and socket or an open-end wrench. Tighten the parts snug, then turn them one-quarter turn farther to make sure they are secure. Turn the tensioner nut on the front of the alternator one-quarter to one-half turn until it is tight.