When you bleed the system (I just replaced a pressure line this week in my car) fill it up off of the ground and rotate the wheel side to side unloaded. Fill the resivoir again, shut the engine off and drop the front down onto the ground again.
Start the engine again. Rotate the wheel steering through the full ratio from one side to the other and back again 3-4 times. Check and top off the resivoir again. As long as the steering wheel does not grab, you have it bled correctly. It may make a small amount of noise. That's normal.
If you have a loud noise and your resivoir is full and you have bled the system, then I would double check that you rotated the steering wheel through it's full ratio and correctly bled the system before calling the auto parts store. Make sure that you don't have any leaks under steering load. Have someone get in the car and rotate the wheel while you look at the underside of the car and in the engine compartment for leaks.
When I bled my system a few days ago, I did it with the front wheels off of the ground and it sounded fine. As soon as I set it back on the ground, it made all kinds of noises as I rotated the wheels until I put more fluid in the resivoir because it pulled more fluid into the system under normal steering tension.
The noise left as soon as the resivoir was full and I had rotated the wheel several times. It needs to be on the ground for the pump to circulate the fluid through the rack. This can only happen when the tires are under ground tension so the pump can actually pressurize the rack and fully bleed all of the air out of the pump, lines and rack.
