Many times, the following part will cure tired tensioning systems.

http://catalog.eautopartscatalog.com/smittys/sa/wizard.jsp?partner=smittys&clientid=sasponline.com&baseurl=http://www.sasponline.com/&cookieid=17R0ZW5V7&year=1991&make=MB&model=300-SEL-006&category=G&part=Acc.+Belt+Tension+Adj.

__________________
Mike Murrell
1991 300-SEL - Model 126
M103 - SOHC
"Fräulein"