power steering pulley nut

I loosened the belt and have a little play on the PS pulley. It's not really bad but it might be causing a vibration and I'd like to get it off to see about replacing the pulley ($182) or just the bearing.

Is there a tool or trick that works to break the 17mm center pulley nut free without an impact?

I tried hitting the end of a breaker bar with a mallet, and it's still just turning the pulley.

I can potentially jam something into a pulley hole and against the power steering pump, but I'm worried about damaging something.

 

You can put a deep socket thru the hole on to one of the bolts to hold the pulley.

 

My trick was break it loose while the belt is still on.

A strap wrench around the pulley to hold it in place.