Power steering adjustment to box?

I have a 73 Valiant with 225 and power steering. The car has all new parts in it and has just been aligned and drives fine. The only problem is the wheel wants turn right on its own. The guy who did the work said that there are 2 springs in the box that control the pressure to one direction or the other when the wheel is tuned. Can these be changed? and where would I get them at? Any help would be great.