F350 Power steering???

I have a 03 F350 6.0 diesel. I noticed a strange noise when turning a corner - different sound from motor as well as specific noise from the engine compartment (sounds like a tire rubbing on the mud flap). I heard the same noise when breaking in a straight line as well. In the parking lot I can turn the wheel without moving and the same noise is heard. Is this the steeering pump on its way out? Does the steering pump also produce the boost for the brakes in these models? How much of a pain is it to replace these pumps.....if it is the pump?
 
Thanks!
 

The P/S pump does produce the power for the brakes too. When it makes the noise check the fluid, usally when the P/S pump gets noisey the fluid will have air in it. If it will make the same noise when not moving by turning the steering wheel or pushing on the brake pedel then I would suspect the pump. The hardest part is getting the pressure hose off the pump, if it makes a 90 degree turn right at the fitting then it is sometimes easier to remove the hose with the pump.