The side of thread on a power steering pump pulley is 3/8-16.
All Type II power steering pumps have a 0.665” shaft diameter except for the 6175ALD-6, 6175ALP-6, 6175ALB-6 and the 6175AL-6 LS pumps, which have a 19mm shaft diameter.
All Type II pumps require a press-on pulley and have a 3/8”-16 tapped center shaft.
To put a pulley back on power steering you will need a power steering pump pulley installer and removal tool.
To use the power steering pump pulley puller you screw one of the bolts that come in the kit into the power steering pump shaft.
Then you place the two moon shaped pieces over the power steering pulley shaft and then use a wrench or socket to tighten the bolt until the power steering pulley comes off.
YouTube has some videos that can explain much better and be a visual which is how I had to learn to use mine.
Here's a link to a good YouTube video that explains how to use the power steering pulley puller.
https://www.youtube.com/watch?v=wTO1sXIbnkk&ab_channel=HowtoAutomotive
It can vary from tool to tool as some tools and pulleys are a bit different when it comes to pulling them off and installing them.
The special tools that are needed for a power steering pump removal is a power steering pump removal tool and installer which is a combination tool that comes in a kit and can be purchased at automotive stores or online.
You'll also need a couple of wrenches or a wrench and a racket and socket to put the power steering pump pulley on.
You cannot hammer on a power steering pulley as the power steering pulley is a pressed fit pulley and requires a power steering pulley installer and removal tool which pushes the pulley onto the power steering pump shaft.
You insert the bolt and tighten into the shaft of the power steering pump and then use the tool with a wrench to push the pulley on as you turn the wrench.
Hammering on a power steering pump pulley will damage the pump and could warp the pulley as well.
You can buy a power steering pump pulley removal tool and installer tool for around $20.00 on eBay which is where I got mine.
The life expectancy of a power steering pump is around 100,000 miles and sometimes longer or around 10 years or more depending on how much you drive.
The symptoms of a failing power steering pump are.
A squealing sound when you start the car.
Groaning noises when you turn the steering wheel.
Steering wheel that is slow to respond.
Stiff steering wheel.
Low power steering fluid and leaking power steering fluid.
And grey power steering fluid.
If your power steering pulley is not spinning then the power steering pump has likely seized up and needs replaced.
The power steering pump pulley should spin with a slight drag when spun by hand and if it's really tight or it won't spin at all then you need a new power steering pump.
A power steering pump should turn freely and the shaft should free spin easily in the housing.
If the power steering pump pulley is hard to turn or the power steering pump shaft is hard to spin then it could be a sign that the power steering pump is going bad.
The pulley on the power steering pump should fit tightly on the shaft and not spin around on the shaft or be loose.
Power steering pump pulleys are pressed on and require a power steering pump pulley installer tool and removal tool.
Never try to pry or hammer on the power steering pump as it can damage the power steering pump.
Also never use a jaw type puller such as a gear puller on a power steering pump pulley as it can damage it.
But if replacing the power steering pump you should always use a new pulley so that it presses on tightly.
Without the friction of the drive belt and the engine NOT running, all driven pulleys should turn freely without noise when spinning by hand.
The P/S pump and water pump pulley will have some drag (resistance) but still turn freely with little resistance when turned relatively slowly.