91 Explorer power steering pulley question

I've replaced my power steering pump on my 91 Explorer but have run into a bit of a problem getting the pulley onto the new pump. I can't seem to get it to stay straight when tightening down the tool for installing it. The pulley just gets crooked on the shaft. Is there a trick that I'm missing here? I've tried spraying the shaft with silicome spray with no success. Have also purchased a new pulley. It isn't the power steering pump and I cannot put the pulley on with the pump off the car because of the way Ford designed how everything bolts in. Any suggestions are most welcome.

For anyone else that runs into this problem, I ended up taking the bracket off the car to work on it. It ended up that when the pulley went on crooked it cut a small groove in the pulley and could not get past it. I smoothed it with emery cloth ande it went on fine. We live and learn....

Thank you for the follow-up and good tip!

And congratulations on the repair.

-Rod