What is Power Steering?

Contel Bradford

Also known as power assisted steering, power steering is a mechanism that helps the driver of an automobile to steer the vehicle. In most automobiles, it relies on a hydraulic system to aid in turning the vehicle’s wheels. It is a standard feature in nearly every modern car and truck.

Power steering is a standard feature in nearly ever modern car and truck.
Power steering is a standard feature in nearly ever modern car and truck.

There are primarily two types of power steering systems, rack-and-pinion and the recirculating ball. Rack-and-pinion is the system found in most vehicles. The recirculating ball is largely known as one of the first systems to be implemented in automobiles. Although not as widespread, the recirculating ball is still used in some modern trucks.

Power steering relies on the vehicle's hydraulic system to aid the driving in turning the tires via the steering wheel.
Power steering relies on the vehicle's hydraulic system to aid the driving in turning the tires via the steering wheel.

A rack-and-pinion system is comprised of two main components: the rack-and-pinion itself and a power steering pump. Situated perpendicular behind the wheels of the vehicle, the rack-and-pinion is generally a piece of metal tubing that is roughly three inches in diameter and three feet in length. Inside the tube, there is a flat piece of metal that has been cut to include teeth on its top. In the center of the rack-and-pinion is a round seal that seals either side of the rack, one at a time.

In these systems, two high-pressure hoses from the steering mechanism are connected to both sides of the center seal. One directs high-pressure hydraulic fluid from the power steering pump to the steering mechanism, while the other allows fluid to flow back to the pump. When the steering wheel is turned left or right, the steering mechanism allows the hydraulic fluid to pass to that side of the rack. It is the pressure that gives the vehicle power an assist by pushing the seal and rack in one direction or the other.

The recirculating ball is a smaller power steering system attached to the vehicle frame on the driver’s side. This system is comprised of a threaded shaft about 12 inches long, in addition to an input shaft that connects to it and the steering column. Aside from the construction, the system works in nearly identical fashion to rack-and-pinion. Power steering fluid passes through the steering mechanism, which aids the driver in turning either left or right.

While new types of power steering have emerged, the core of most systems is the pump, complimented by a belt that is powered by the vehicle’s engine. Even the older recirculating ball system borrows the pump’s concept of moving high-pressure fluid back and forth. Due to the fact that the hoses moving the fluid are susceptible to developing leaks, drivers are encouraged to have them inspected by an auto mechanic during every oil change.

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Discussion Comments


Before my husband and I were married, he had an old beat up car. It was a big, very heavy car and it didn't have any power steering. It had it at one point, but something happened and he never got it fixed.

I didn't know what a big deal it was until I tried to drive it. I couldn't. I literally couldn't turn the steering wheel. I had no idea that power steering was so helpful! I don't know how my husband did it. He must have been very strong. Who ever thought that driving could be a work out?

Were the first cars made without power steering? If so, they must have been either very light, or very hard to drive.


My old van leaked power steering fluid. We didn't have the money to fix it right away, so we just kept putting more power steering fluid in it. I could always tell when it needed more, because it would get hard to turn the steering wheel. And when I did turn it, it made an awful noise. Each and every time it happened, we would pour more fluid in.

While it wasn't exactly cheap to buy power steering fluid all the time, it was a lot less than the repair would have cost. We did this for quite some time.

It turned out to be a bad idea. The problem got worse and worse until it led to more problems and I found myself broken down on the side of the road, with an over-heated van. Who would've thought a power steering problem could lead to that?

I should have just gotten the original problem fixed in the first place. I thought it was just an inconvenience to have to work harder to turn. I had no idea it could lead to way worse problems, and a lot more money spent on repairs.

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