Alright, So my car stopped last week and it was sitting all week so I had to change out the alternator yesterday(162k miles). This morning I gave it a cold start and the belts squealed a little and I gave it gas and it quit squealing. So I let it run for a little with the air on to give it some charge on the battery(died last week). While it was running I was looking at the belts and it was running fine, gave it a couple revs and it sounded fine. I let it run with the hood open and all of a sudden something started to rattle, and I shut it off.

I came back thinking the belt pulley was too tight, so I gave it a little leeway and tightened it a little less and started her up again.. A minute passes while its running and the rattle comes back, so I shut it off again. I then remembered that during the alternator swap I had changed the little bushing that comes in the bottom-right hole of the alternator, with the one from the previous alternator (shorter by an 3/4"), because the long bolt wouldnt go through the larger bushing. That shorter bushing looks to be causing the alternator to shake in its place, but stops when the accelerator is depressed.

*Picture of a Honda Alternator to show the Bushing*



What I need to know is, why did the new alternator come with a longer bushing then what was in the old alternator?

 

Are you sure that the bushing was physically longer? A reman or new alt has the bushing usually puseed out of the hole so that when you install it between the bracket it will "center" itself when installed

 

Fixed it, What the problem was, was that the bushing is longer but if you push it through it wont fit with the alternator in its place, so we left it sticking out some and pushed it in and it sat correctly..