whining noise when steering....HELP!!!

I have replaced the power steering pump and it's still making this moany whining noise, moreso when I turn the steering wheel even just an inch and hold any pressure on it. I was thinking maybe it was the a/c compressor clutch bearing, but I ran a shorter belt and bypassed the compressor and it's still doing it. :crying: Anyone know what else could be causing it?? Thanks ahead of time!!!

If service has been done and there is air in the system it will cause the pump to make a whining sound.

Procedure for purging PS system of air.

Raise the front of the truck off the ground with stands.
Add fluid to the reservoir until at full mark.
Disconnect the ignition coil connector.
Do not hold steering wheel on stops. Crank engine for 30 seconds while cycling the steering wheel fully to the left and right.
Check the fluid level and add to the Full mark.

There is an air purge procedure using a hand held vacuum pump if there is still air in the system.
Remove the reservoir cap and install a rubber stopper, line, and hand held vacuum pump to the top of the reservoir.
Start the vehicle.
Apply 20 to 25 inches of vacuum for minimum of 3 minutes at idle.
Release the vacuum and remove the pump.
Fill reservoir to full mark.
Put the vacuum pump on again and pump it down to 20 25 inches.
Cylcle the steering wheel fully to the left and right every 30 seconds for approximately 5 minutes.
Turn engine off.
Release the vacuum and take off pump.
Check fluid level and bring up to full.
Start the engine
Cycle the steering wheel to the left and right for 30 seconds for approximately 5 minutes. Do not hold wheel against stops.

Repeat the above if air is still in there.

Bad news. The pump could have been damged if it was run with air in the system.

Thanks for the reply. Part of the procedure for replacing the pump was to bleed the system of air. I actually did the process twice just to make sure. I've checked for bubbles and there is no air in the system. I held a stethoscope to all of the pulleys last night and discovered that it's coming from the ps pump. I've heard that ford ps pumps are loud like that. So I guess that's what I've come up with unfortunately. The steering feels fine while I'm driving so I don't really think there is a problem, just an irritating noise.

My Ranger and the Aerostar I use to have did the same thing. They are just noisy pumps. Might want to check the air pressure in your front tires as well. I notice that when my pressure is down even a little bit in my truck, the pump gets a lot louder. Truck tires are much more difficult to turn so the pump works a lot harder when they are even just a little low.