Power Steering Pump problems of the 2004 Nissan Altima

Problem vehicle is 2004 Nissan Altima with 50,000 miles. Noticed when driving that steering wheel was binding when I tried to turn the vehicle. Seems like power steering is going out. Had everything checked with fluid and power steering pump. Not that so during the course of the drive the steering wheel would bind both during turning and when returning the wheel to straight. The binding (requiring both hands) to turn the steering wheel and also required extra effort to return the wheels to straight because the binding prevented the wheels from returning to straight . The binding is bad enough that it could cause an accident I am scared to drive it. Because of the effort required to turn the wheel and the difficulty in straightening the wheels. The binding force was intermittent and seemed to be related to certain places in the orientation of the wheel. After research on the internet I discovered that many other people are having this problem with similar year and model of car. Is there a recall for this problem. It really needs to be major accidents could happen. I am affraid the steering is going to go out comletely and cause a head on collision.