You can drive with a broken power steering pulley but you won't get far until the belt breaks and or the pulley comes off the shaft and you lose power steering.
If your power steering pulley is broken or is bad or the power steering pump is out you can drive but only for a short distance and it will be hard to steer.
It's best to replace the broken power steering pulley and pump before you drive and have it towed if needed instead.
If your power steering pulley is loose it could be that the pulley has developed cracks inside where the shaft fits or the shaft has gone bad on the power steering pump or if you put an old pulley on the new power steering pump it could be that the power steering pulley shaft hole is spread out too far and not able to fit again.
It's always best to use a new power steering pulley with the new power steering pump as they are pressed fit and require a tight fit using a special tool to install properly.
A power steering pump pulley is not supposed to be loose although the shaft should spin freely but the pulley should fit tight on the power steering pump shaft when pressed on fully.
If the power steering pump pulley is loose it will eventually fall off and it means that something is wrong with the power or the shaft of the power steering pump.
The tool that is needed to remove and install a power steering pump pulley is a power steering pump pulley remover and installer tool.
You can buy the power steering pump pulley installer and removal tool on eBay, Amazon or at an auto parts store.
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.