mb 300sel

[rneinc]

Hi:
i have a 300 sel 4 days ago the smog pump pully bearing went bad so i took the serpentine belt of and remove the pump got it back yesterday but when i put it all back the serpentine belt made a squeel noice i tought that maybe the tensioner was not on good but after i check it all thru i found that the crank pully turns at a faster rate than the belt and the other pullys so i removed them and all are spinning loose , the question is why does the crank pully turns faster even when accelerated but not the belt and other pullys even thoe there all loose and before i remove the smog pump it was running good , im puzzeled because im not a rookie at mechanics but this has me beat.thanks for any help you can bring me .
Ron

[ctaylor738]

Is the surface of the belt glazed? Has the belt stretched and/or worn to the point that the tensioner can't hold it tight enough? Is the tensioner working correctly? From my 300E days, I believe that there is a pointer on it that need to be in the right position.