Wierd... AC clutch noise after belt swap. Whats that about?

[billschroeder5842]

Huh, what would cause my AC clutch to start grinding after swapping a serpentine belt?

I'm chasing down (see other posts) a chirp-chirp under the hood. Here is what I have done:

1) new belt tensioner pulley
2) new AC bushing and cleaning of clutch surfaces
3) clean/light scuff of (with 600 grit sand paper) all spinning wheel surfaces
4) checked all spinning assembly with "the hose" method- all quiet

I put the old/new (4k miles) belt back on and got the chirp immediately. A few squirts of Windex and the chirp immediately disappeared. The chirp came back in a few seconds but the squirt of Windex quieted the sound right away. NOTE: the AC ran well and the compressor was quiet.

Clearly I had a belt issue, so I swapped the belt for an old belt (14K miles) for fun and to test. I started and the chirp was gone immediately. I went to test the AC and when I put on the AC, the clutch immediately make a grinding noise that was pretty constant. This grinding was consistent with the on/off of the switch and the engine was quiet with the engine off. My whole "testing" cycle was less that 30 seconds as I did not want to mess up the AC clutch.

So, what would causes with clutch to start making a noise? Is the belt pulling at a different angle (I'm not sure how)? Is the solution to tighten/loosen the nut on clutch or is this a new clutch and plate assembly solution?

This is just weird.