Pulling into my driveway this morning, a strange sound starts, and the power steering stops. I immediately shut it down and found this. WTH happened?

 

OK let me rephrase that. I know what happened, just curious what may have caused it. Just old and worn out like me?

 

Not sure how that shaft is fixed to the impeller hub.
Maybe a snap ring, or retainer clip failed. Maybe a press fit loosened with time. Maybe a bearing seized.

I think Habanero recently dismantled one of these pumps, maybe she will chime in with details of the pumps internal construction.

 

I would need to set down and look at a pump and mine is buried in the snow some place.

either the shaft broke did it make noise or what holds it broke or came loose

been quite a while since I had one apart my tired brain can`t remember just what holds it in place without looking!!

 

Thanks for the responses. The truck is on the back burner right now due to family health issues.