The hydraulic steering system in your car is comprised of a number of high-stress components that are exposed to extreme heat, chemicals, and pressure. The power steering pump is a critical component of this, forcing hydraulic fluid into the rack and pinion (or steering box), assisting the movement of the steering wheel. With age, a power steering pump will begin to make grinding or squealing noises at full lock, indicating bearing wear. Bad seals and leaks are also a common failure point of power steering pumps.