2003 Chevrolet Venture Power Steering

I replaced the power steering pump and pulley. Primed the pump the way the instructions said to. I did jack the van up, turn the wheels with the engine off, then started it up and turned the wheel both directions, turned it off and let it sit for approximately 10 minutes. Checked fluid level and turned wheels again. Started up again and turned wheels. Lowered jack and tried to turn, and the wheel is very hard to turn. Repeated process and received the same results. The pump is screaming a low tone, the fluid is full and see no signs of fluid being pumped. Also before installing the new pump we did pump out the old fluid and pumped in new fluid. Could it be the pump or the rack? Or maybe something else or something I am doing wrong. If you could help it would be greatly appreciated. Thank you for your time.