actually, you SHOULD loosen all three through bolts, the one on the pivot point of the bracket allows it to pivot easier so you don't bend the adjuster bracket. it's very finicky...
so to sum up, you should loosen the bolt closest to the block on the pivot of the bracket, the bolt that is attached to the long adjuster bolt, and the bolt at the bottom of the alternator. THEN loosen/tighten the actual adjuster bolt. then tighten all the rest...
that equals a total of 4 bolts that need to be loosened and tightened.

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 190D 2.5Turbo
1987 190D 2.5-5SPEED!!!

1987 300TD
1987 300TD
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!