The steering wheel makes unusual noises and feels particularly heavy. Could the power steering be broken?

When we are driving, we often encounter various problems, and abnormal steering noises are one of the more frequently asked questions on forums.

But I believe that when we talk about cars and car repairs, the steering system is a system we often overlook. Today, let's talk about an important component of the steering system: the power steering.

Before talking about the power steering pump, we first need to have a basic understanding of it. In fact, many people know about the power steering pump and know that it is used for assistance.

Simply put, whether the steering system in a car is a rack-and-pinion type or another form, turning the steering wheel directly would feel very 'heavy.' The power steering pump is a component that helps make steering easier.

If we were to categorize them, the power steering systems equipped on our cars can roughly be divided into three types according to Baidu Encyclopedia: 'mechanical hydraulic power steering system, electro-hydraulic power steering system, and electric power steering system.' 

These three types of power steering systems, however, each have their own differences. Let's talk about this further below.
 

Mechanical hydraulic power assistance is the most common type of power steering pump operation. It has existed since 1902 and can be considered a 'century-old establishment' in the field of power steering.
 

The main components of this device basically include the hydraulic pump, oil pipes, pressure and flow control valve body, V-belt drive, and oil reservoir, among others. 

To briefly explain the working principle, its core principle is to divert a portion of the engine's power, convert it into hydraulic oil pressure through the power steering pump, and then use this pressure to drive the hydraulic cylinder to generate force, assisting us in steering.

The advantage of this type of power steering is that it is particularly mature and low-cost. However, its disadvantage is also very obvious: in vehicles equipped with this kind of power steering, regardless of whether you are turning the wheel or not, the power steering pump is always operating.Especially in the segmented type of hydraulic power systems: the constant-pressure hydraulic power steering system, it always ensures that the pressure in the lines remains high at all times.

Although keeping high pressure is not a problem, don’t forget one thing: increasing the hydraulic pressure consumes engine power. If the system is working without steering, the engine power is wasted, which naturally leads to higher fuel consumption. Moreover, during critical stages such as starting or climbing when the engine power is already strained, this main method may cause the steering wheel to feel heavier due to insufficient power, affecting our driving experience.
 

In fact, the structure of the electro-hydraulic power assist system is quite similar to that of the mechanical hydraulic power assist, and the principle is also almost the same. The only difference is that its power source is provided by a motor instead of directly from the engine.How should this be understood? As we mentioned earlier, the mechanical hydraulic power assist does not operate all the time, consuming engine power and increasing fuel consumption, right?

Then let's try a different approach: instead of having the engine provide power to the power steering pump to pressurize the steering fluid, we directly convert it into an electric power steering pump, using the vehicle's electricity to pressurize the fluid and start operating.
 

What are the benefits of this? Unlike mechanical structures, motors can be controlled by an electronic control system to turn on or off, and even the amount of force they provide can be regulated.

In this way, a car equipped with an electronic hydraulic power-assist system can not only shut off the power pump when not in use, saving fuel, but the system can also control the level of assistance based on the car's speed and usage.

For example, when moving the car slowly, the electric power steering pump can operate at full power, making the steering wheel lighter. At high speeds, the pump can operate at a lower output, making the steering heavier and the vehicle more stable.Because it offers better performance and is more energy-efficient, more and more cars are now using this type of steering assistance. However, if we compare efficiency, there are options that are even higher.

In addition to what we mentioned earlier, there is another type of electric power steering system. The EPS we sometimes see on certain vehicles (mainly microvans) is this type of assistance.

Its principle is even simpler, and we can understand it like this: it directly places a motor on the steering mechanism, letting the motor help us apply force. However, if we look at it in detail, its installation position can vary a lot.

Since this system no longer has a hydraulic system, it eliminates the energy conversion from the motor to hydraulic pressure and from hydraulic pressure to power assist. With fewer conversions, the efficiency naturally improves. Therefore, in theory, it is less likely to break down and is more efficient.

Of course, just like the entire vehicle, even the best power steering system won't perform well without maintenance and care. So, what should be paid attention to when using these types of power steering systems?
 

In simple terms, mechanical hydraulic power steering relies on the power steering fluid within its system to function, so during normal use, it is important to ensure that the fluid level in the reservoir is never low. Additionally, since the internal fluid is under high pressure, we should avoid turning the steering wheel to the end for extended periods of time.

As for electronic hydraulic power steering, the points to watch out for are basically similar to those of mechanical hydraulic power steering.

Regarding the EPS electronic power steering system, because its structure is very simple but highly electronic, generally we only need to pay attention to whether there are any fault codes or abnormal sensations.

Of course, aside from the issues mentioned above, if one day you suddenly find that your car's steering wheel has become heavier or there are unusual noises when steering, be sure to check the steering system immediately.

Since we mentioned malfunctions, let's take this opportunity to talk about the common causes of failures in the hydraulic power steering system. This way, when we encounter problems in the future, we can prioritize checking these issues first:1. Insufficient hydraulic oilThe direct feedback of insufficient hydraulic oil is difficulty in steering and a heavier steering wheel. In addition to this, a lack of oil can also prevent the components from getting proper lubrication and heat dissipation, which may lead to abnormal noises and excessive wear.
 

2. Hydraulic oil deterioration or contaminationApart from insufficient hydraulic oil, if the hydraulic oil has been used for too long, it may deteriorate, causing increased viscosity and poor flow, which in turn can lead to abnormally high pressure, making the steering wheel heavier. In severe cases, the power steering pump may also be damaged.Contaminants, and even air, can also cause issues in the power steering system. Simply put, impurities in the oil can clog the pipelines or enter components, causing abnormal wear on the power steering pump. Air, on the other hand, can cause unstable force transmission, making the steering effort sometimes strong, sometimes weak, or inconsistent.For this problem, first check the power steering oil filter. If it is clean, timely replacement of the power steering fluid may resolve the issue.

3. Power Steering Pump DamageIf your car suddenly has a very heavy steering wheel or strange noises while steering, and the above issues have all been ruled out, then you should consider whether there is a problem with the power steering pump itself. At this point, professional mechanics will need to perform testing.

● Editor's Note:In fact, the power steering system has developed many advanced technologies over time, such as variable steering ratios and collapsible steering columns. I remember the first time I encountered electronic power steering was during the era when the Santana 2000 was just released. At that time, in a certain car model, after turning the steering wheel, it not only felt like there was a slight delay in steering, but a motor noise could also be heard from under the steering wheel. However, today, electronic power steering in cars can achieve fast, precise responses and even provide road feel feedback. The progress has been remarkably quick.