I went out the other day and got myself a new alternator because it appears that you can't change the diode after all... Now, even with a broken bracket, the old alt allowed the serpentine belt to draw itself tight so everything would be turned by the crank. New reman alt from Advance Auto, and my belt is so loose I can turn the alt pulley by hand with the tensioner drawing the belt as tight as it can. Now, I removed the old alternator in the same cold I put the new one in at, and the belt has quite a lot of slack, almost like it's too long or jumped a pulley or something, but it's on all the pullies and I have no idea what to do. Should I go out and buy a new belt? What's the diameter of the stock Delco pulley?

 

I don't know what the diameter is, but there are really only a few things that could be wrong. Compare the pully diameters on the old vs new alternators. As long as they are the same, that's out of the question. Then, doublecheck your belt routing. My newest thirdgen has been an 87, so I don't have any experience with the serpentine belt routing. I'm trying to imagine if a misclocked alternator could give you a problem. I don't think it can, since the front cover of the alternator has both the threaded hole and the unthreaded hole in it. Maybe somebody has a picture showing belt routing?

 

I didn't change the belt routing when I removed the old alt, I just unlooped it from the two pullies-that is, the alt and tensioner pullies-and put it back on again. And yes, I do have the factory belt routing sticker. I have no way to compare the pullies because I had to trade in the old alt to get the new one.