If the pump were not pumping at all, you would have to really use muscle power to turn the steering wheel back and forth. It sounds like you can turn the wheel reasonably easily. If you just replaced the steering rack it will take some driving for the system to bleed out. Has the fluid ever been changed or the rack? If all are original, they could be near the end of their life, although I have found the Saginaw pump (GM and cheap) is a very reliable unit. Hope this helps.