I just dropped in a brand new motor as some of you may know. Well, I purged the bubbles out of my new power power steering pump, but am still having problems. I checked and I have enough fluid, but when I turn, it sounds like a damn cat hissing at me. Should I continue to try to purge the bubbles with the wheels off the ground? How can I tell if it's just a bad pump that I'll need to exchange?