What Is Power Steering

How it works

Power steering is a mechanical device installed on a vehicle that reduces the effort needed to turn the steering wheel, which is making it easier for the vehicle to turn or maneuver at low speeds. There are three main types of power steering systems such as hydraulic power steering (HPS), electric power steering (EPS) and hydroelectric power steering (EPHS).

The most common power steering systems used today are HPS and EPS.

Hydraulic power steering

Using hydraulic pressure supplied by an engine-driven pump, or power steering pump, this pressure assists the motion of turning the steering wheel. The power steering pump is turned by a serpentine belt, or accessory drive, providing pressurized power steering fluid to the power steering hose and ultimately delivering it to the power steering control valve at the steering gear.

Power steering fluid is kept in a fluid reservoir that’s maintained by the low side power steering hose that returns fluid at low pressure.

HPS does have its drawbacks. Because the power-steering pump equipped on most vehicles runs constantly and pumps fluid all the time, it wastes horsepower. This wasted power translates into wasted fuel and higher emissions. Hydraulic power steering systems are also prone to leaks and noises and commonly result in failure due to a broken serpentine belt.

Electric power steering

In this system, an electric motor replaces the components that make up an HPS. The motor, which is separate from the vehicle engine, is installed on the steering rack or steering column. An electric power steering system is often the preferred system because of its efficient fuel economy and lower emissions.

Additionally, EPS is customizable by vehicle type, road speed, and even driver preference and it eliminates environmental hazards of leakage and disposal of hydraulic power steering fluid.

Finally, if the engine fails or stalls, electrical assistance continues to function.

Electric power steering VS Hydraulic power steering

Modern vehicles offer one of two distinct systems: electric power steering or hydraulic power steering. Both work to provide easier, more responsive steering control. However, the way they work is completely different. 

Electric power steering relies on an electric motor to assist drivers in turning the steering wheel. This system is highly efficient, only consuming power whenever assistance is needed. It provides improved fuel economy since the electric motor draws power from the vehicle’s electrical system, helping to reduce the engine load. Electric power steering systems are generally lighter and more compact, making the overall vehicle weight lighter. The system also offers greater flexibility and adjustability, easily integrating with other vehicle systems and features, including advanced driver-assistance systems. Electric systems also allow for various steering modes to create a customizable steering feel and responsiveness based on preferences or driving conditions. Hydraulic power steering uses hydraulic pressure that is generated by a pump to assist steering. These are usually more robust and capable of handling heavier loads than electric systems, which is why it’s more commonly used in larger vehicles, trucks, and SUVs, to offer more stability and control. Hydraulic systems maintain steering assistance even if the engine is off so the vehicle can still be maneuvered in an emergency. While these do offer some advantages, they are less efficient than electric systems because of the continuous power consumption required to operate they hydraulic pump. They, unfortunately, are prone to leaks and require periodic maintenance to check and refill the fluid. Hydraulic components are also more complex, meaning higher manufacturing costs and potentially higher repairs costs required if they fail. Which power steering system is better will ultimately depend on your vehicle’s size, intended use, fuel efficiency needs, and desired driving experience. However, most standard vehicles will include electric power steering unless you are purchasing a heavy-duty vehicle with high towing or load capacity.

How often does your power steering need maintenance

Your vehicle’s power steering system, although imperative to its performance, is a delicate system that requires a professional’s service to maintain correctly. You should perform a fluid check regularly to ensure it’s properly filled and your filter should be changed annually. When necessary, your steering system fluid will need to be flushed and replaced. 

If your power steering system is in need of service, there are some symptoms to look out for. These include:

1. Whining noises when turning the wheel

2. Difficulty or resistance turning the steering wheel

3. Leaking red liquid underneath the car