I see you're not getting many responses here. I'm no expert, but to me that does not sound normal nor does it sound like a bearing. Sounds like something external to the pump is hitting something when you rotate the pulley. Can you get an inspection mirror to see behind the pulley, or maybe even remove the pulley if that is not too hard? Based on that noise I'd be surprised if anything bad is going on inside the pump, but you should figure it out.