BMW Repair: idler pulley removal, alternator belt, 740il

Question
I am trying to replace the idler pulley/pulleys on the Alternator belt in a 1998 740iL they are squealling, I checked with a stethoscope and it is definitely one of the pulleys and not the alternator.  I need to know how to relieve tension on the belt so I can remove the pulleys.  I assume you need to remove the fan first but after that I can't find how to back the tensioner off.

Thanks
Matt

Answer
You're lucky!  I replaced an alternator on a friend's '97 740iL a week ago, so still have it fresh in my memory (and the scratches on my hands haven't healed yet).

DON'T need to remove the fan. Remove the two bolts that hold and adjust the pulley.  You have to loosen them to get the belt off, then once loosened, just continue to take them out.