How do you replace the alternator on a 1990 Mercedes 300E?

Answer 1

Hi,I just replaced the alternator, pretty easy, I couldn't find out how to loosen the pulley drive belt, I just removed the wires from the back of the alt., removed 2 bolts that hold the alt. on, the alt. slide out very easily. The radiator fan and the cowling around the raditor was also removed, Assembly was done in reverse order, I hope this description was some help, Peter. Melbourne, Australia I would like to add to this answer because this answer is missing 2 critical steps, first be sure you have or have made a diagram of the belt path and second, and very important is to loosen the belt tensioner. The tensioner on the 300E is a rod located on the drivers (or your right if you are facing the engine from the front of the car) side of the engine near the front. It is about as thick as a woman's index finger. It sticks out near the top at kind of a 45 degree angle with a little bit of a hex shape at the top and a hole in the middle. You turn that following the "Lefty Loosey, tighty righty" rule until the tension on the belt is loose enough that you can remove and replace the alternator. Be careful not to strip it. If you do, it is a fairly inexpensive part, (it was $13USD when I made this mistake :) )but it is more work and not too fun. It is tight space and a pain in the hands to do. The job is much easier if you have the right MB tools for the job, that one bolt is a real pain to get to. Good luck :)