Power steering pumps are belt-driven pumps that use pulley mechanisms attached directly to the pump housings. These pulley mechanisms, which are circular in shape and have small, open grooves machined onto their sides, are driven by rubberized belts that mesh securely with the pulley grooves. These belts are attached to other belt-driven engine components, and are ultimately powered by the spinning motion of the engine crankshaft. Power steering pumps are equipped with inner rotor mechanisms, components that spin rapidly and are responsible for pressurizing power steering pump fluid.
As the power steering belt turns, which ultimately turns the power steering pump pulley, the power steering pump rotor, which is attached directly to the pump pulley, starts to spin inside the power steering pump. The spinning action of this rotor mechanism is what pressurizes the power steering fluid, and propels it out of the power steering pump unit and into the rest of the power steering pump system. This pressurized power steering fluid provides the lubricating and heat-reducing properties needed to ensure adequate power steering system function, as well as the fluid pressure needed to turn the power steering gear located in the power steering gear box.
To ensure adequate power steering pump function, the power steering belt needs to be adjusted to ensure proper tension. A belt that is too loose can easily slip off the power steering pump pulley, thus rendering the power steering pump ineffective. A belt that is too tight can wear prematurely, make noise or break. Power steering belt tension is adjusted according to each individual vehicle's specifications. During normal vehicle maintenance inspections, power steering belts are normally inspected and checked for any signs of wear and/or breakage, and promptly replaced.
