C5 Power steering faulty

[Slernu]

Hi guys! Im having problem with my C5 II (2006 2.0 petrol).
Had occasional power steering faulty with stiff steering which can disappear in 5 minutes to 2 days.

Things i have done:
-Bleed the system trough reservoir
-Checked fluid level and topped it to appropriate level
-Checked wiring going to pump
-Battery voltage and fuse is fine

Im have minor leak in rear left sphere.

Any ideas what to check/do?

[GiveMeABreak]

If you have a leaky sphere you'll probably be getting air back in the system, so bleeding it will serve little purpose until you've sorted the leak.