power steering pump is part of the suspension of your vehicle. Its purpose is to make your steering easier and smoother. In addition they tend to make driving at high speed safer by helping to avoid over-correction accidents.
A power steering pump is a hydraulic pump consisting of small ports which allow the fluids into the steering gear box. This fluid is put under hydraulic pressure to turn a drive belt. The drive belt drives the steering shaft which in turn works on the steering rack. The latter allows you to move the car’s wheels from left to right.