Steering pulls hard one way then the other.
 

Hi, I have an 01 F250, 4x4. All ball joints and ends are new. Everything is tight underneath. Sometimes when I make a 90 degree turn, when it straightens out it goes hard the other way, pulling into the next lane. Sometimes it just starts to pull while going straight. I am thinking maybe the booster????? Is this a possibility or is the steering box more likely? It doesn't always do it so I don't think it is mechanical, more hydraulic. Tires are good and alignment is also good.
Thanks for any help.

Sounds like an axle shaft U joint might be froze up. Turn the wheels all the way in either direction, reach into the U joint and turn the shaft to see if there is any resistance / binding.

Thanks for the reply. I had to do some work today and just got home. I will try it first thing in the morning. Never thought of that problem.

Well I checked both sides and nothing seems wrong. I have had it to the front end shop and they couldn't find anything either. Can it be the valves that switch the steering pressure from one side to the other? I even switched tires to see if it would help, but no change.