I mentioned in another thread that I was chasing an intermittent noise (they always only make noise for the wife don't they?) in my wife's Outback. The problem got bad enough that I became certain it could only be the power steering. And it did misbehave for me yesterday. VERY loud noise.
after a coupla failed attempts to stop the power steering pump from sucking in air, (you could see bubbles and foam in the tank) today I got a replacement o-ring for the suction hose housing on top of the pump. That seems to be working. MUCH less noise. I still want to do some lock-to-lock 'purging' as outlined in the document AS posted (thank you) and I had some trouble that required me to make an xtra trip for a replacement bolt - but, Ace hardware was able to match the o-ring (be sure to tell them it's a metric application)' Before this o- ring replacement, I had tried putting some heavy grease on the part and the mating surfaces of the housing. I also change the clamps on the hoses in 3 places. Only changing the o-ring seems to have solved the problem. Hopefully, the o-ring from Ace can survive in this location!
hope this might help someone else in the future.