I just replaced/tightened the alternator belts on my '83 240 because they were getting old and the alternator also seemed to stop charging in wet conditions (without squeaking, strangely enough). I replaced all the other belts (including the timing belt) while I had things apart, and all that seemed to go well.

Now that I have everything back together, I can't seem to get the alternator belts tight enough. A bit embarrassing, but I'm not sure about how to proceed. Bentley is useless in this regard (though great in almost all others!).

I did find a post on the forums suggesting that one use Channellocks to move/hold the alternator in place while tightening the bolt. I did this--by prying the end of the loosened alternator bolt towards the end of the channel it slides through--and got it pretty tight, but they still seem a little looser than they should be.

Any other tips for the older cars that don't have a handy screw-based tensioner but rely on brute force (?) to achieve the correct tension? When measuring deflection, how hard is one supposed to push on the belts?

Good news is the battery is charging again, quite well, probably thanks to the new-ish rubber and belt dressing I put on.

Thanks,
Tobias