I have done everything I can think of to resolve this power steering screeching/squeeling problem.  I cleaned and roughed up the pullies, deglazed the belt but the noise continues.  I sprayed the belt with water while the engine was running which did not effect the noise.  I tried loosening and tightening the belt. The noise is almost like a grinding sound.  I am starting to wonder whether the noise could be coming from the pump bearing or something else inside the pump.  Has anyone else experienced a screeching or squeeling power steering pump?  Any suggestions on how to diagnose the problem as coming from the pump before I spend a bunch of money on a pump rebuild (which may or may not solve the problem)?  This is an original Eaton Pump.