Q: Noise when turning the steering wheel.

Hello. Noises when you turn the wheel can be caused by many things. A few common causes are worn steering or suspension components, or as you stated a problem with the power steering pump or system. The steering and suspension systems have various moving parts that can produce noise if they wear out or dry up. If the ball joints have already been replaced then a few other things I would look at are the inner and outer tie rod ends, the sway bar links, and the control arms. If the joints or bushings to any of these components wear out or dry up they can cause produce a squealing noise from the steering. It may also be possible that there is an issue with the power steering system. If the system runs low on fluid, or the pump fails, it may produce a squealing sound when the steering wheel is turned. This will usually come accompanied with a change in steering wheel tension, often time an increase in required effort to turn the wheel. Checking the power steering fluid and turning the wheel with the hood open may help determine if this is the case. If you are unsure I would recommend having a professional technician, such as one from YourMechanic, come to your location to diagnose the cause of your steering wheel noises.