Power steering has revolutionised the driving experience, making it easier to manoeuvre vehicles of all sizes. This crucial system reduces the effort required to turn the steering wheel, enhancing driver control and safety. Understanding how power steering works and knowing what to do if it fails can be vital for every driver.
Modern vehicles employ either hydraulic or electric power steering systems, each with its unique components and functionality. As automotive technology advances, electric power steering is becoming increasingly prevalent due to its efficiency and reduced maintenance requirements.
Hydraulic power steering systems: components and functionality
Hydraulic power steering systems have been the standard for decades, utilising fluid pressure to assist in turning the wheels. The main components of a hydraulic system include the power steering pump, reservoir, hoses, and the steering gear.
The power steering pump, driven by the engine via a belt, pressurises the hydraulic fluid. This pressurised fluid flows through hoses to the steering gear, which translates the hydraulic pressure into mechanical force to assist in turning the wheels.
When you turn the steering wheel, a valve in the steering gear opens, allowing pressurised fluid to flow to the appropriate side of the steering mechanism. This fluid pressure reduces the effort required to turn the wheels, making steering smoother and easier, especially at low speeds.
Hydraulic power steering systems can generate up to 1,500 psi of pressure, providing significant assistance to the driver.
One of the advantages of hydraulic systems is their robust nature and ability to handle high loads. However, they require regular maintenance, including fluid checks and replacements, to ensure optimal performance.
Electric power steering: modern advancements and efficiency
Electric power steering (EPS) systems have gained popularity in recent years due to their efficiency and reduced maintenance requirements. Unlike hydraulic systems, EPS uses an electric motor to assist steering, eliminating the need for hydraulic fluid and associated components.
The core components of an EPS system include an electric motor, a torque sensor, and an electronic control unit (ECU). The torque sensor detects the driver’s steering input, and the ECU processes this information along with vehicle speed data to determine the appropriate level of assistance.
There are three main types of electric power steering systems:
Rack-assisted electric power steering (REPS)
In REPS, the electric motor is mounted directly on the steering rack. This configuration provides precise control and is commonly used in larger vehicles due to its ability to handle higher loads.
Column-assisted electric power steering (CEPS)
CEPS systems have the electric motor mounted on the steering column. This design is more compact and is often found in smaller vehicles where space is at a premium.
Direct drive electric power steering
This system uses a high-output electric motor directly connected to the steering gear. It offers the most precise control and is typically found in high-performance vehicles.
Electric power steering systems offer several advantages over hydraulic systems, including improved fuel efficiency, as they only draw power when assistance is needed, and reduced maintenance requirements due to the absence of hydraulic fluid.
Power steering fluid: types, maintenance, and replacement
While electric power steering systems don’t require fluid, hydraulic systems rely on power steering fluid to function correctly. This fluid acts as a hydraulic medium and lubricant, protecting the system’s components from wear and corrosion.
There are several types of power steering fluid, including:
- Mineral oil-based fluids
- Synthetic-based fluids
- Automatic transmission fluid (ATF)
It’s crucial to use the type of fluid specified by your vehicle’s manufacturer. Using the wrong fluid can lead to seal damage and system failure.
Regular maintenance of your power steering fluid is essential for the longevity of the system. This includes checking the fluid level and condition, as well as replacing it at the intervals recommended by your vehicle’s manufacturer.
On average, power steering fluid should be replaced every 50,000 to 100,000 miles, but always consult your vehicle’s manual for specific recommendations.
When replacing power steering fluid, it’s important to bleed the system to remove any air bubbles that could cause erratic steering behaviour. This process typically involves turning the steering wheel from lock to lock several times while the engine is running.
Common power steering failures and diagnostic techniques
Despite their reliability, power steering systems can experience failures. Recognising the symptoms and understanding diagnostic techniques can help you address issues before they become severe.
Pump failure: symptoms and causes
A failing power steering pump often manifests as a whining or groaning noise when turning the steering wheel. This noise may be accompanied by difficulty in steering, especially at low speeds. Common causes of pump failure include:
- Wear and tear over time
- Low fluid levels causing internal damage
- Contaminated fluid leading to increased friction
Diagnosing pump issues often involves checking fluid levels, inspecting the drive belt for wear, and listening for unusual noises during operation.
Steering rack leaks and wear
The steering rack is a critical component in both hydraulic and electric systems. In hydraulic systems, rack leaks can lead to fluid loss and reduced steering assistance. Signs of rack issues include:
- Fluid puddles under the vehicle
- Stiff or inconsistent steering
- Clicking noises when turning
Diagnosing rack problems typically involves a visual inspection for leaks and checking for excessive play in the steering system.
Electric motor and sensor malfunctions
In electric power steering systems, issues with the electric motor or sensors can lead to steering problems. Symptoms may include:
- Intermittent loss of power assist
- Steering that feels too light or too heavy
- Warning lights on the dashboard
Diagnosing these issues often requires specialised diagnostic equipment to read error codes from the vehicle’s ECU.
Belt and pulley system issues
In hydraulic systems, the power steering pump is driven by a belt connected to the engine. Problems with this belt or pulley system can affect power steering performance. Signs of belt issues include:
- Squealing noises, especially when starting the engine
- Intermittent loss of power steering assistance
- Visible wear or cracks on the belt
Regular visual inspections of the belt and pulley system can help prevent unexpected failures.
Emergency procedures for power steering failure
Knowing how to react in the event of power steering failure can be crucial for maintaining control of your vehicle and ensuring safety on the road.
Safely manoeuvring with manual steering
If you experience a sudden loss of power steering while driving:
- Remain calm and maintain a firm grip on the steering wheel
- Gradually reduce your speed and activate your hazard lights
- Look for a safe place to pull over, avoiding sharp turns if possible
- Be prepared to use significantly more force to steer the vehicle
Remember that while steering will be more difficult, it is still possible to control the vehicle manually. Avoid panic braking or sudden movements that could destabilise the car.
Roadside troubleshooting steps
Once you’ve safely pulled over, you can attempt some basic troubleshooting:
- Check the power steering fluid level (for hydraulic systems)
- Inspect the drive belt for signs of damage or slippage
- Look for any visible leaks or damage to steering components
- If safe to do so, restart the engine to see if the problem persists
If the issue appears to be a simple fluid loss in a hydraulic system, topping up the fluid may provide temporary relief. However, this is not a permanent solution, and the underlying cause should be addressed promptly.
When to call for professional assistance
If you’re unable to identify or resolve the issue, or if you’re uncomfortable driving the vehicle, it’s best to call for professional assistance. This is particularly important if:
- There are visible leaks or damage to steering components
- The steering feels unusually heavy or unresponsive
- You hear unusual noises when attempting to steer
- Warning lights related to the power steering or electrical system are illuminated
Professional mechanics have the tools and expertise to diagnose and repair power steering issues safely and effectively.
Preventative maintenance and power steering longevity
Regular maintenance is key to ensuring the longevity and reliability of your power steering system. By following these preventative measures, you can reduce the likelihood of unexpected failures and maintain optimal steering performance:
- Regular fluid checks and replacements (for hydraulic systems)
- Inspection of belts and hoses for wear or damage
- Addressing unusual noises or steering behaviour promptly
- Following manufacturer-recommended service intervals
For electric power steering systems, while they require less maintenance, it’s still important to have them inspected regularly as part of your vehicle’s overall maintenance schedule.
By understanding how your power steering system works and being proactive about its maintenance, you can ensure safer, more comfortable driving and potentially avoid costly repairs down the road. Remember, when in doubt about any aspect of your vehicle’s steering system, it’s always best to consult with a qualified automotive professional.