How Does The Power Steering Rack Work?

Originally featured on our website.

As most people are aware, your car’s steering wheel is used to direct the car in different directions. Cars today are greatly assisted by power assisted steering systems that allow drivers to turn the car without needing to apply an equal amount of force. But how can a simple turn of the wheel get a two thousand pound car to change direction? This is because of the power steering rack in your car.

What is a Power Steering Rack?

A steering rack is probably the most important component of your car’s wheel system. The rack directs pressure towards your car’s two front wheels and allows for the car to turn without excessive force by the driver. It is designed to move in a straight line back and forth between the tires so that the car is never thrown of its axis and maintains forward energy. The steering rack connects to a tire rod which attaches the rack to the wheel base.

The rotation of the steering wheel communicates with the steering rack thanks to the car’s pinion. A pinion is a rotating gear that moves along another geared component to allow for movement back and forth. A long metal rod called the steering column attaches the gear of the pinion to the steering wheel.

When the steering wheel is turned, the pinion rotates along the geared part of the power steering rack, which pushes the rack side to side. These sideways movements by the steering rack are what push your car’s wheels to turn left or right.

In order for the steering rack and pinion system to work properly, they must turn either wheel at a specific angle. When your car in turning, you might think the two front wheels are still parallel to eachother.

Contrary to this belief, the two front wheels do not share the same angle when turning. This is due to the fractional force between the road and the tires. If the front two wheels of a turning car were actually facing the same angle, the tires would slip of its path. The perpendicular angles of each front wheel eventually meet on the axis of your back set of wheels so a circular turn can be made.

How Electric Power Steering Works

In order to completely remove the required force to turn your car’s steering wheel, modern cars utilize what is called electric power steering. This works due to a brushless motor attached to the car’s steering column.

By receiving inputs such as your car’s speed and the torque applied to the steering wheel, the motor assists in the rotation of the steering column. Thanks to this motor and its gear system, The effort needed to turn the steering wheel is lessened because most of the work is being handled by the power steering electric control unit.

Signs of a Bad Steering Rack

Since steering is such an important aspect of driving, it is crucial to notice if something seems wrong with your power steering rack. The most common symptom of a bad steering rack is a loose or firm steering wheel. If you notice your steering wheel is rotating much to easily or that it will barely budge, there’s a chance the connection from your steering wheel to the steering rack is broken.

Another common sign is a shaking steering wheel. If you are driving at higher speeds and notice your wheel or car is shaking, there’s a chance the steering rack is not properly balanced. It is also possible that your wheels are not properly aligned.

You may not notice any changes in the sound your car makes if the steering rack is damaged. This is converse to when a power steering pump is failing as those will make a whining or groaning noise.

Power Steering Rack Replacement Cost

If you realize that your car needs some work and you’re wondering how to replace a steering rack, it is a rather complicated task. Due to the tools needed and raised access to the car, it will be hard to handle this project if you’re not a mechanic or lack a car lift.

Replacing the steering rack involves accessing the car’s engine bay and undercarriage. Since the steering rack and pinion are connecting so many components, a lot of labor is required to take everything apart. If the problem lies with the steering wheel, the steering column, or the pinion then it is possible to access these parts through the wheel well opening.

The cost to replace a power steering rack will range between $600 — $1000, which consists equally of parts and labor expense. Depending on the make and model of your car or how difficult it is to access the steering rack, the replacement cost will vary.