Rattling / 300SD Alternator Tensioner Adjustment?

[chetwesley]

Can anyone give me good advice on how to properly adjust the belt tension on the alternator on a '83 300SD?

It seems that my inner belt is a little loose, while the outer one is fine. It seems there are two aspects to the tension - the bolt that fits between that little fork (which does very little as far as I can tell), and then the sliding adjustment in the mounting bracket, which seems to be adjusted by the bolt in the bracket.

The reason I ask is that I am getting a loud rattling from the area of the alternator which comes and goes. Visually, I can not see anything causing the noise, but the inner belt does seem loose as I mentioned, so I am wondering if the alternator being a little cockeyed is causing the fan on the alternator to rub on something. The noise sounds similar to when I once had a loose alternator pulley and fan and the fan was bouncing around on the shaft.

Any other ideas of what the noise could be? Loud tinny rattling from the area where the alternator is.

Thanks as always.