I swapped out the alternator this weekend before I saw this Picture. I couldn't figure out why the adjustment bolt had about a 1/2" long bolt welded to the back side of it. With the tensioner bolt broken, there is nothing to keep the larger adjustment bolt from turning, plus the little piece of remaining tensioner bolt , made it nearly impossible to put a back up wrench on it. This also makes it very difficult to properly adjust tension.

__________________
1989 300E
103,500 miles

1982 300SD
Sold but not forgotten