My new pump came with an "installer".
It's actually just a long bolt with a square nut and a washer on it.
Thread the bolt into end of PS pump pulley/shaft,
hold bolt with wrench while you turn the square nut against the pulley,
pressing it on.
It was a PITA just because the fan and shroud are so close.
I got the installer set where the wrench would rest agains the steering gear box, but the pulley started to spin and back out the installer.
I had to hold the pulley still, so it wouldn't spin under the torque.
Pure Sucked, I am glad I am done with that R&R.