Power steering: how it works and works in modern cars

What is power steering and why is it needed?

Imagine: you are trying to turn the steering wheel in place without an engine - the wheels barely budge, and your hands are shaking from the load. It solves this problem power steering (RU). This is a system that multiplies physical effort of the driver, making steering turns easy even when maneuvering in a parking lot or at low speed. Without it, driving a modern car - especially a heavy crossover or minibus - would turn into a grueling workout.

The first amplifiers appeared in 1920s on trucks, and to 1950s they began to be installed on passenger cars. Today more than 98% of new cars are equipped with power steering - this is the standard for safety and comfort. But how exactly does this system work? Why is the steering wheel in some cars “tight”, while in others it turns “with one finger”? And what happens if the amplifier suddenly fails? Let's sort it out in order.

Three types of power steering: which is better?

Modern cars are equipped with one of three types of amplifiers. Each has its own pros, cons and pitfalls in operation. The choice of type depends on the class of the car, its price and even environmental standards (for example, EUR more energy efficient power steering, which is important for hybrids).

Let's consider all three options:

• 🔧 Hydraulic booster (power steering) - a classic that runs on oil pressure. Reliable, but requires maintenance (fluid replacement every 60–100 thousand km).
• ⚡ Electric amplifier (EUR) - compact, economical, but sensitive to overheating. Often installed on budget models (Renault Logan, Hyundai Solaris).
• 🔄 Electrohydraulic booster (EGUR) - a hybrid of the first two. Retains power steering smoothness, but the pump is driven by an electric motor rather than a belt from the engine.

Which one is better? There is no clear answer. For example, power steering indispensable for heavy SUVs (Toyota Land Cruiser, Nissan Patrol), where maximum reliability under extreme loads is needed. A EUR ideal for city babes (Volkswagen Polo, Kia Rio), where fuel economy and simplicity of design are important.

How does hydraulic power steering (power steering) work?

Operating principle power steering based on the laws of hydraulics: the fluid pressure created by the pump helps turn the wheels. Let's break down the process step by step:

1. Pump (driven by a belt from the engine) creates oil pressure in the system (~80–150 bar).
2. When turning the steering wheel spool valve opens the fluid channel in the desired direction.
3. Oil enters under pressure power cylinder, which turns the wheels.
4. The more you turn the steering wheel, the more the distributor opens - and the more actively the hydraulics “help”.

The key element of the system is power steering fluid. It not only transmits pressure, but also lubricates parts, preventing corrosion. Special oils are used (for example, ATF Dexron II/III or PSF), which cannot be mixed with conventional transmission fluids - this will lead to seal failure.

Power steering component	Purpose	Typical faults
Pump	Creates oil pressure	Wear of blades, oil seal leakage, noise
Distributor (spool)	Directs fluid flow	Jamming, play, uneven operation
Power cylinder	Converts pressure into mechanical force	Leaking seals, rod corrosion
Hoses and pipes	Transporting liquids	Cracks, breaks, blockages

⚠️ Attention: If you hear when turning the steering wheel creaking or squealing, this could mean the power steering fluid level is low or the pump drive belt is worn. Ignoring the problem will lead to pump jamming and expensive repairs.

Electric power steering (EPS): pros and cons

EUR - This is a completely electronic system, where the role of an “assistant” is played by an electric motor, not hydraulics. Its main advantage is energy efficiency: the engine turns on only when you turn the steering wheel, saving fuel (up to 0.3 l/100 km in the city). In addition, EUR Maintenance-free: no fluid to change, no belts or hoses to leak.

But there are also disadvantages:

• 🔌 Sensitivity to overheating — during prolonged operation (for example, off-road), the motor may turn off for cooling.
• 🛠️ Difficulty of repair — electronic units are often beyond repair; the entire unit must be replaced.
• 🎛️ "Artificial" steering feel - some drivers complain about the lack of “feedback” from the road.

Interesting fact: in EUR often used brushless electric motor (like in drones or electric bicycles) which is controlled ECU (electronic control unit). This allows you to adjust the “heaviness” of the steering wheel depending on the speed. For example, on Volkswagen Golf or Skoda Octavia The steering becomes lighter in parking lots and heavier on the highway for better stability.

Why can the EUR turn off while driving?

The electric power steering is protected against overheating. If you maneuver for a long time (for example, in a parking lot in the heat), the engine may reach a critical temperature (usually >85°C), and the ECU will temporarily turn it off. The steering will remain functional, but will become heavier. To return to normal operation, just let the system cool for 5–10 minutes.

Electrohydraulic power steering (EGUR): the golden mean?

EGUR combines advantages power steering and EUR: there is a hydraulic part (cylinder, liquid), but the pump is not driven by a belt from the engine, but separate electric motor. This solution is popular on premium cars (Audi A6, BMW 5-series) and some crossovers (Toyota RAV4).

Benefits EGUR:

• ⚡ Economical - the pump only works when the steering wheel is turned (as in EUR).
• 🔧 Reliability — hydraulics can withstand loads better than pure electronics.
• 🎯 Accuracy - smooth operation like power steering, but without loss of engine power.

However EGUR more difficult to repair than power steering, and more expensive than EUR. For example, replacing a pump with an electric motor with Mercedes-Benz E-Class may cost 40–60 thousand rubles (against 15–20 thousand for a regular pump power steering).

Rumble or vibration when turning the steering wheel|Fluid leaks from the reservoir|The steering wheel turns jerkily|The amplifier icon is lit on the panel (🚗 with an exclamation point)-->

Typical power steering malfunctions and their causes

Any system breaks down sooner or later - power steering is no exception. Signals of problems are usually noticeable immediately: the steering wheel becomes stiff, extraneous sounds or leaks appear under the hood. Let's look at the most common breakdowns for each type of amplifier.

Power steering: what breaks most often

• 💧 Liquid leak — hoses crack or pump seals wear out.
• 🔊 Pump noise - wear of bearings or blades (often due to old fluid).
• 🔄 Steering play - output in the distributor or rack.

EUR: weak points

• 🔌 Electric motor failure — winding burnout or brush wear.
• 📱 ECU failure — errors in the firmware or corrosion of contacts.
• 🔥 Overheating — blocking operation during prolonged load.

EGUR: combined problems

• ⚡💧 Leak + electrical - for example, a short circuit in the pump motor due to liquid ingress.
• 🛠️ Wear of the hydraulic part - as in power steering, but with the addition of electronics.

⚠️ Attention: If on the go Steering power is completely lost (the steering wheel has become “oaky”), pull over to the side of the road immediately! B power steering it could be a broken pump belt, EUR - engine failure. Driving a car without power assistance is dangerous, especially at high speed.

How to extend the life of your power steering: 7 practical tips

The service life of the amplifier depends not only on the quality of the parts, but also on driving style. Here's what you can do to avoid expensive repairs:

1. Do not hold the steering wheel in extreme position longer 5 seconds (especially in Power steering/EGUR) - this creates maximum pressure in the system and wears out the pump.
2. Check the fluid level (for Power steering/EGUR) every 10 thousand km. The optimal level is between the marks MIN and MAX on the tank.
3. Use only recommended oil. For example, for Hyundai/Kia — PSF-4, for VW/Audi — G 004 000.
4. Monitor the condition of the pump belt (in power steering). Cracks or slippage will result in loss of pressure.
5. Do not wash the engine with high pressure - water can get into the electronics EUR or corrode the seals power steering.
6. Periodically “bleed” the system (for Power steering/EGUR): With the engine off, turn the steering wheel all the way in both directions - this will remove air.
7. At the first sign of trouble (creaking, tight steering wheel, leaking) contact service. Repairs at an early stage are 2–3 times cheaper.

An interesting life hack: if in power steering appeared air (the steering wheel twitches, the fluid foams), you can try to remove the plug yourself. To do this:

1. Raise the front of the car on jacks (the wheels should be hanging).
2. Start the engine and turn the steering wheel all the way left and right several times.
3. Add fluid to the level and repeat the procedure.

If the problem persists, professional pumping is required.

FAQ: Frequently asked questions about power steering

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

Technically, yes, the steering will remain functional, but driving the car will become extremely difficult, especially at low speeds. For example, expand Toyota Camry Without an amplifier in a parking lot, only a trained person can do it. On the highway there is less risk, but maneuvering (overtaking, turning) will require significant effort.

Important: If the amplifier turns off due to a malfunction (for example, a broken belt power steering), eliminate the cause as soon as possible. Driving for a long time without oil power steering will lead to rack failure.

Which power steering is more reliable: power steering, electric power steering or electric power steering?

According to service center statistics:

• power steering - the most durable (resource 200–300 thousand km), but requires regular maintenance.
• EUR — reliable in the city, but afraid of overheating and moisture (resource 150–200 thousand km).
• EGUR - golden mean, but repairs are expensive (resource 250 thousand km+).

Definitely for SUVs and heavy vehicles power steering. For city babes - EUR. For premium sedans - EGUR.

What happens if you mix power steering fluids of different colors?

The color of the liquid (red, yellow, green) indicates its composition and compatibility. For example:

• Red (for example, Dexron) - mineral or synthetic, compatible with ATF for automatic transmission.
• Yellow - universal, often used in Mercedes-Benz.
• Green - only for hydraulic systems, incompatible with others!

Mixing incompatible liquids (for example, green and red) will lead to:

• Destruction of seals and seals.
• Foaming and loss of oil properties.
• Pump or distributor jammed.

If you don’t know what kind of liquid is poured - completely drain the old one and fill in the new one.

Why does the steering wheel become heavier in the cold?

B power steering and EGUR The liquid thickens in the cold, and it is more difficult for the pump to pump it. B EUR the problem may be:

• Low battery (motor lacks power).
• Thickened grease in the amplifier gearbox.
• Temperature sensor error (ECU limits assistance).

Solution: Use winter liquid for power steering (for example, Febi 32600 with freezing temperature -40°C), check the battery and warm up the car before driving.

Is it possible to repair the power steering yourself?

Depends on the type of fault:

• Power steering: Replacing fluid, pump belt or hoses is possible even for a beginner. Repairing a pump or rack is difficult and requires special tools.
• EUR: You can check the fuses and connectors yourself. Repair of the motor or ECU - only at the service center.
• EGUR: Most work (except for adding fluid) requires diagnostic equipment.

For diagnostics EUR/EGUR you need a scanner (for example, Launch X431) to read errors from the ECU. Without it, you will only guess the problem.