You have to loosen the bolt on the attachment to the block that will allow the adjustment arm to pivot. The spacer cylinder will be a challenge to replace but without it you won't be able to tighten the alternator without deforming the bracket. Might have to wiggle the alternator to get that bolt out. I found it easier to turn the star bolt from the front. Used a torque wrench for the extra length. Make sure the belt is not in the way. This could
be blocking the bolt. It is a pretty easy thing to do once you've done it three or four times. I wish I could say Ive only had to do it once.

__________________
Kevin

1978 300D
1979 240D