Power steering: what it is, how it works and when repairs are required

Power steering is one of the key components of a modern car that many drivers take for granted until it fails. Without this system, driving your car turns into hard physical work: imagine having to turn the steering wheel with both hands, even when parking or maneuvering at low speeds. This is especially acute on large SUVs or commercial vehicles, where the weight of the front axle can exceed 1 ton.

Today, power steering is found in three main variations: hydraulic (power steering), electric (EUR) and combined electrohydraulic (EGUR). Each system has its own advantages, disadvantages and “diseases” that every car owner should know about. For example, hydraulics is famous for its reliability, but requires regular monitoring of the fluid level, and electrician more economical, but sensitive to overheating. In this article, we will look at how the power steering works, what signs can be used to determine its malfunction, and what to do if the steering wheel has become “stiff” or extraneous sounds appear.

What is power steering and why is it needed?

Power steering is a mechanism that reduces effortrequired by the driver to turn the wheels. Without it, driving a car would be extremely difficult, especially at low speeds or when maneuvering. Imagine that you need to park in a narrow place while turning the steering wheel with force 15–20 kg - this is exactly how much is required to turn the wheels of an average sedan without a power booster.

Main functions of the system:

🔄 Ease of management — reduces the load on the driver’s hands, especially during long trips.
⚡ Increased security — allows you to quickly react to a traffic situation (for example, when avoiding an obstacle).
🚗 Driving comfort — minimizes vibrations and shocks from road unevenness transmitted to the steering wheel.
📉 Reduced fatigue - critical for truckers and drivers who spend more than 4-5 hours a day behind the wheel.

Interestingly, the first power steering appeared in 1920s on trucks, and they began to be installed on passenger cars only in 1950s. Today, even budget models are equipped with at least electric amplifier, and premium brands (Mercedes-Benz, BMW, Audi) offer adaptive systems that adapt to driving style and road conditions.

Types of power steering: comparison of power steering, electric power steering and power steering

All power steering is divided into three main types, each of which has unique features. The choice of system depends on the design of the car, its class and year of manufacture. For example, hydraulic boosters still found on many cars 2000–2010s, whereas electric became standard for models after 2015.

Amplifier type	Operating principle	Benefits	Disadvantages	Typical faults
Power steering (hydraulic)	It works due to the fluid pressure created by a pump, which is driven by a belt from the engine.	✅ Reliability ✅ Smooth operation ✅ Suitable for heavy vehicles	❌ Requires maintenance (fluid replacement) ❌ Engine power loss ❌ Sensitive to leaks	🔧 Liquid leak 🔧 Pump wear 🔧 Damage to hoses
EUR (electric)	Uses an electric motor, which directly or through a gearbox helps rotate the steering column. Controlled by ECU.	✅ Energy efficiency ✅ Does not require liquid ✅ Easily adjustable to driving modes	❌ Sensitive to overheating ❌ Difficult repair ❌ High replacement cost	🔧 Sensor failure 🔧 Wear of engine brushes 🔧 Problems with the ECU
EGUR (electrohydraulic)	Hybrid system: The pump is driven by an electric motor rather than by a belt from the engine.	✅ Keeps power steering smooth ✅ Less load on the engine ✅ Compactness	❌ Expensive service ❌ Sensitive to liquid quality ❌ Complex diagnostics	🔧 Hydraulic leaks 🔧 Pump electric drive failure 🔧 Fluid contamination

Electric amplifiers (EAS) today lead in prevalence: they are installed on 70% of new cars (2023 data). This is due to stricter environmental regulations (for example, Euro 6/7), where every horsepower lost in the power steering pump drive affects fuel consumption and CO₂ emissions. However hydraulics still remains the preferred choice for SUVs and commercial vehicles due to its reliability under extreme loads.

How power steering works: from turning the steering wheel to turning the wheels

The principle of operation of power steering depends on its type, but the general scheme remains similar: the driver turns the steering wheel, the system “understands” his intention and helps turn the wheels with minimal effort. Let's look at the process using an example hydraulic booster, as the most obvious:

Turn the steering wheel → The steering wheel transmits force through the shaft to spool valve (valve that determines the direction of fluid movement).
Pump activation → The power steering pump, rotated by a belt from the engine, creates pressure in the system (usually 80–150 bar).
Moving Fluid → Under pressure, liquid enters one of the cavities power cylinder, helping to move the rack or steering knuckle.
Turning wheels → The force from the cylinder is added to the mechanical force of the driver, and the wheels turn.

B electrical amplifiers Instead of liquid, an electric motor operates, which receives signals from sensors:

📶 Torque sensor — determines with what force the driver rotates the steering wheel.
📊 Steering position sensor — fixes the rotation angle.
🚗 Speed sensor — adjusts the force depending on the speed (at high speeds the steering wheel becomes “tighter” for safety).

The ECU analyzes this data and sends a command to the electric motor, which through a gearbox or helps rotate the steering shaft.

Why does the steering feel stiff at high speed?

This is provided by the amplifier design for safety reasons. At speeds above 100 km/h, the system artificially increases steering resistance to prevent sudden maneuvers that could lead to loss of control. In the electric steering system this is regulated by software, in the power steering - due to the design of the distributor.

Signs of a faulty power steering: when is it time to diagnose

Any power steering system will wear out sooner or later. The main thing is not to miss the first “bells” in order to avoid expensive repairs. Here top 7 symptomsthat talk about problems:

🔊 Extraneous sounds — a hum, creaking or howling when turning the steering wheel (for power steering this often indicates pump wear, for electric power steering it indicates problems with the motor bearings).
💪 Increased force — the steering wheel has become “stiff”, especially at low speeds or when parked.
🌀 Jerks or dips — the steering wheel “twitches” or turns unevenly.
🩹 Fluid leaks (for power steering/electric steering) - puddles under the car are red or brown (the color of the power steering fluid).
🔥 Steering rack overheating — after a long ride, the rack becomes hot to the touch.
🚨 Amplifier icon lights up on the dashboard (steering wheel light with an exclamation mark).
🔄 Spontaneous turning of the steering wheel — the wheels “steer” to the side without driver intervention.

Critical faultwhich is often ignored: gradual decrease in the fluid level in the power steering without visible leaks. This may indicate internal wear of the oil seals or seals of the pump, which will lead to its complete failure. In the EUR, a similar symptom is the “jamming” of the motor due to wear of the brushes or bearings.

⚠️ Attention: If the power steering has completely failed (the steering wheel rotates with enormous force), don't continue driving - it's dangerous! This is especially critical at high speeds, where loss of control can lead to an accident. Call a tow truck or tow the car with the front axle hanging up.

Power steering diagnostics: what you can do yourself

Some problems with power steering can be identified without visiting a service station. Let's start with visual inspection:

Checking power steering fluid:
- Open the hood and locate the fluid reservoir (usually marked with a cap that says PSF or Steering).
- The level should be between the marks MIN and MAX. The color of the liquid is red or amber (if it is dark or with flakes, replacement is required).
Inspection of the power steering belt:
- Check the belt tension (when pressing with a finger, the deflection should be 10–15 mm).
- Look for cracks, delamination or signs of wear.

Leak test:

Start the engine and turn the steering wheel all the way left and right. Have a helper inspect the hoses and connections for leaks.

For electric amplifier Diagnosis is more difficult, but you can check:

🔌 Fuses — find in the fuse block the one that is responsible for the electric power steering (indicated in the manual).
🔧 Connectors — inspect the contacts on the amplifier motor (they often oxidize).
📱 Diagnostic scanner - even inexpensive devices (for example, ELM327) may show errors on the EUR (codes C1010–C1099 for most brands).

⚠️ Attention: If you hear when turning the steering wheel metal grinding, this may indicate critical wear worm pair in the rack or shaft bearings. In this case, further operation of the vehicle prohibited — urgent replacement of the unit is required!

💡

When checking the power steering fluid level, always clear any dirt from the dipstick or reservoir cap to prevent debris from entering the system. Even small particles can damage the pump or distributor.

Repair or replacement: what to do if the power steering breaks down

The cost of power steering repair depends on the type of system and the nature of the problem. In some cases it is enough prevention (for example, replacing fluid or belt), in others it will be necessary major renovation or complete replacement of the unit. Let's look at typical scenarios:

Malfunction	power steering	EUR	Repair cost (average)
Liquid leak	Replacing pump/rack hoses or seals	Not applicable	from 3,000 to 15,000 ₽
Pump wear	Pump repair or replacement	Not applicable	from 8,000 to 25,000 ₽
Electric motor failure	Not applicable	Replacing the motor or control unit	from 15,000 to 40,000 ₽
Steering rack wear	Rail repair or replacement	Rail repair or replacement	from 20,000 to 60,000 ₽
Problems with the ECU	Not applicable	Reflashing or replacing the block	from 10,000 to 30,000 ₽

Important nuance: steering rack repair - it's always a lottery. Even after restoration, the node can last from 20,000 km up to 100,000 km, depending on the quality of spare parts and the skill of the mechanic. For example, on Volkswagen Passat B6 or Ford Focus 2 slats often “leak” after repair due to poor-quality seals. In such cases, it is more appropriate to set contract rail (used in good condition) or new.

For electrical amplifiers repair usually comes down to replacing:

🔄 Electric motor (if the windings or brushes are burnt out).
📱 Control unit (in case of software failures or failure of microcircuits).
🔌 Sensors (torque, steering wheel position).

Please note: on many vehicles (eg Hyundai Solaris, Kia Rio) The EUR is assembled with the steering column, and its replacement costs 30 000–50 000 ₽.

💡

When choosing between repairing and replacing the power steering, focus on the mileage of the car. If the car is older than 10 years or the mileage exceeds 200,000 km, it is more advisable to invest in a new part rather than repair the old one.

Prevention and care: how to extend the life of your power steering

The service life of the power steering directly depends on your driving style and regular maintenance. Here 5 rulesthat will help avoid breakdowns:

🔄 Do not hold the steering wheel in the extreme position for more than 5 seconds — this creates a maximum load on the power steering pump or electric power steering motor. It is especially dangerous at high engine speeds.
🛢️ Change power steering fluid every 60,000–80,000 km (or once every 2 years). Use only the fluid recommended by the manufacturer (for example, Pentosin CHF 11S for BMW or Toyota PSF for Japanese cars).
🚗 Avoid driving through deep puddles — water that gets on a heated rail can cause corrosion or damage to the anthers.
⚡ Monitor the on-board voltage — voltage surges (for example, due to a faulty generator) can damage the power steering control unit.
🔧 Check the crankcase protection and rack — a damaged boot or lack of protection will lead to dirt getting in and premature wear.

For electrical amplifiers It is especially important to avoid:

🔥 Overheating — do not leave the car in the sun with the ignition on (for example, when washing).
💧 Moisture ingress - Even a small leak through the seals can cause corrosion of the contacts.
🛠️ Self-repair without diagnostics — errors when replacing sensors or motors can lead to incorrect operation of the system.

Interesting fact: on some models (Tesla, premium audi) power steering can study according to your driving style. For example, if you often drive off-road, the system adapts and makes the steering “lighter” at low speeds. However, after replacing the ECU or motor, this “memory” must be reset through diagnostic equipment.

FAQ: Frequently asked questions about power steering

Is it possible to drive without power steering if it is broken?

Technically yes, but it is extremely dangerous and uncomfortable. Without power steering, the steering becomes very stiff, especially at low speeds. At high speeds, control becomes more difficult due to the lack of feedback. We recommend that you immediately contact service or call a tow truck.

Which power steering is better: power steering, electric power steering or electric power steering?

Each type has pros and cons:

power steering - reliable, but requires maintenance and “steals” power from the engine.
EUR - economical, but expensive to repair and sensitive to overheating.
EGUR - the golden mean, but difficult to diagnose.

Optimal for the city and small cars EUR, for SUVs and trucks - power steering or EGUR.

Why does the power steering pump hum when cold?

This is a typical problem with hydraulic boosters. Reasons:

Thickened liquid (needs to be replaced with a more frost-resistant one, for example, ATF Dexron VI).
Worn pump bearing (needs repair or replacement).
Air entering the system (power steering needs to be bled).

If the hum does not disappear after warming up, diagnose the pump.

Is it possible to fill the power steering with transmission oil instead of a special fluid?

Absolutely not! Power steering fluids have special additives that protect rubber seals and prevent foaming. Gear oil (eg. ATF) can only be used as a last resort and for a short period of time, if this is expressly permitted by the manufacturer (indicated in the manual).

How long does power steering last?

The service life depends on the type and operating conditions:

power steering — 150,000–250,000 km (with regular fluid changes).
EUR — 200,000–300,000 km (but the electronics may fail sooner).
EGUR — 180,000–250,000 km.

In practice, the resource may be reduced due to aggressive driving, lack of maintenance or an accident.

Power steering: device, principle of operation and fault diagnosis