Power Steering Pump on 2004 Explorer

My power steering pump was bad it made a moaning/whining noise I was told by the mechanic that I needed to drive the 2004 ford explorer 500 miles for the pump to settle and the noise will stop, well it hasen't stopped as a matter of fact it's gotten worst especially when stopped it gets real loud and moaning/whining then it seems like the truck wants to cut off, what needs to be done to fix this problem it's really driving me crazy to hear this noise all the time.