What is power steering? Arguably, one of the best innovations in vehicles since the wheel. Vehicles have not always been equipped with power steering. In fact, this improvement has only been around for about 50 years or so and in the beginning was only used in luxury vehicles. Through the years, however, this modern-day application has gradually been implemented into all vehicles and has improved greatly since its inception.
The Power Steering Wheel
Simply put, power steering is what helps you turn the steering wheel with ease. Sure, without it, your arms would rival those of a Greek god, but there’s more than meets the eye when it comes to power steering. Power steering systems today change the ease of steering to enhance the feel for the driver. The act of steering the vehicle is actually achieved between the steering wheel and a gear system. You may have heard the term rack and pinion when referring to power steering at some point. This is because rack and pinion is the most common steering gear system in most cars and trucks today. The rack is a linear gear that, instead of being round, is long and flat with prongs on one side. The rack is attached to the steering spindles by the tie rods. The pinion is a circular gear that attaches to the steering shaft attached to the steering wheel. When the wheel is turned, the pinion gear rotates, moving the rack back and forth making the wheels turn either left or right.
Hydraulic & Electric Power Steering
Hydraulic, or HPS (high pressure steering), consists of a recirculating ball steering gear or the rack and pinion gear. Both are considered power steering assist systems, allowing the driver to steer the vehicle if the engine, which powers the power steering pump, isn’t running and thus not supplying fluid to the steering gear. Hydraulic systems use the power of the engine with the use of a belt attached to the pump to circulate power steering fluid throughout the system.
What does power steering fluid do? This mighty fluid actually transmits the power in power steering. The power steering pump circulates the fluid under pressure, enabling the hydraulic piston in the steering gear to move, greatly reducing the effort needed to turn the steering wheel. The rotary control valve sends pressure to a piston, based on the direction you wish to turn, while releasing it from the opposing side. As the pressure builds, the piston moves making the wheels turn left or right. Because of the improvements in modern vehicles, the systems of today are able to sense the speed of the vehicle and slow the input from the steering wheel to the steering gear to reduce the sensitivity at higher speeds for safety.
Over time, dirt, and debris along with weakened power steering components, may contaminate power steering fluid. That’s why it’s important to have the power steering fluid flushed every 30,000 miles. Avoiding this service, could cause the pump to work harder and wear out prematurely. In between flushes, be sure to check the fluid level. Not sure how to check power steering fluid? Use our quick and easy guide and reference your owner’s manual for specific details for your vehicle:
- Check the fluid after the car has been running and warmed up. The vehicle is normally checked with the vehicle shut off.
- Locate the power steering reservoir (usually indicated in the owner’s manual) and identifying the label on the reservoir cap.
- Remove the cap.
- If the reservoir is made of clear plastic, identify the full and low indicator lines on the outside of the tank to determine the fluid level. If the reservoir is metal or obscure, using the dipstick, wipe the fluid on the dipstick off with a clean rag. Then, dip the dipstick back into the reservoir and check the level. The dipstick will indicate the fluid level remaining in the tank.
EPS, or electric power steering is a bit simpler as the vehicle’s computer is responsible for easing the steering process. The EPS system is most often equipped with a small electric motor that is either placed at the base of the steering column or directly on the steering rack. Unlike the hydraulic system, EPS does not use the power of the engine, which increases fuel economy. When a driver wants to turn, the computer is able to translate the turning of the steering wheel to an electric motor that assists in moving the rack and pinion back and forth. Similar to HPS, the electric system varies the sensitivity at higher speeds for increased safety. Because the only fluid that this system uses is in the rack and pinion, it is not a serviceable unit and does not require fluid flushes.
When To See an Expert
When turning becomes a difficult process, a fluid leak or component failure may be to blame. If the vehicle is hard to control or has too much “free play” and wanders, it’s time to take your vehicle to a certified repair center. Did you know that improperly mounted or balanced tires can also affect the system?
A technician will inspect the vehicle and provide a detailed explanation on what is needed to resolve your vehicle’s steering issues. A simple flush or even a tire balance may be all your vehicle needs to alleviate the difficulties in the power steering system. Who can you turn to when you need an expert for your power steering troubles? Sun Auto Service! Visit our locations page to find a service center you can trust for all your automotive needs.