Thanks for the links.

My pump makes noise only when the clutch is engaged, the pulley bearing is OK. I think it may have been replaced by the PO. The internal pump bearings appear to be in good shape. I have successfully lubricated the front bearing, it is now quiet and smooth when I spin it manually. My theory is that when the rubber vane material wears, it leaves behind a dust residue. This dust gets in the bearings and causes them to make noise. I'm hoping that a good cleaning and a bit of grease will work.

I'll let you know what happens when I reinstall it this weekend.