Power Steering pump locking up, help diagnosing?

2004 Automatic. I noticed I would turn, then midway or so the steering wheel would slightly jerk then be hard to turn. Did some digging and noticed my pump pulley would lock up when turning and a nasty little squeal ensued from the belt being forcefully pulled. I have a used pump I got for free plus reservoir and bracket. Anyone tips on if I should check the rack or whatnot PLEASE let me know and help me out.

The issue typically happens when its cold/after sitting but sometimes it persists. Not noticing any leaks, filled up with UV addative and checking daily now however i’m not too sure where to check.