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One of the most important driving aids in modern vehicles is the power assisted steering system,and power steering relies on a specific type of fluid in order to operate.



What is Power Steering Fluid?

  • Power steering fluid is a crucial component in making the driver’s job easier and safer. It provides hydraulic assistance to the steering system when the driver turns the steering wheel. The nature of the hydraulic system allows the effort applied by the driver to be multiplied many times to help turn the wheels. Without this assistance, the tires would encounter considerable resistance from the pavement underneath and require extra (and sometimes significant) effort from the driver.

    How Does Power Steering Fluid Work?

    • A pump is attached to the vehicle’s engine and operated by a belt, which circulates the hydraulic fluid within the system to apply a force multiplier to the wheels. When the steering wheel is activated, valves spring into operation to control the flow of liquid through a hydraulic cylinder, which in turn will apply force to the steering gear. As the driver turns the wheel even further, additional fluid is released and pumped through the cylinder, so that extra force is applied to the wheels. Often, a detection device known as a torsion bar is fitted to the bottom of the steering column, which will twist proportionately to the torque being applied. This bar in turn controls the valve, which allows the fluid to enter the cylinder.

    How Is Power Steering Fluid Made?

    • Some manufacturers recommend the use of transmission fluid to operate power steering systems, but most are silicon or mineral oil derivatives. Additives can be included to help reduce friction, corrosion, and wear.

    How Does Power Steering Fluid Fail?

    • It can degrade and lose its efficiency.
    • It can leak from seals or pipes.
    • It can become contaminated.

    What Are the Symptoms of Failure?

    • High-pitched "squealing noises" especially when driving slowly.
    • Bubbles or foam within the fluid, indicating air or water in the system.

    What Are the Consequences of Failure?

    • The power steering pump will break down and make steering operation more difficult.

    Hydraulically-assisted power steering is a relatively new invention, and while it is not necessary to actually operate the car, it makes driving easier and safer. Today, the tendency is to replace hydraulic systems with electrically assisted versions.

    If you have questions or concerns about power steering fluid or any of your vehicle's components, come into your local Pep Boys where we can answer any question, help you find any part, or perform any vehicle service you might need.