After I published the article, questions about the remaining nodes rained down on my blog. Namely, how to determine a particular malfunction. And now several people are asking a question about the wheel bearing, namely how to understand that it is faulty. Today I will also try to explain simply and clearly how to determine the breakdown with my own hands ...

The wheel bearing is a very important element, without it the wheel of the car would not spin. It experiences really high loads, and therefore must be made of wear-resistant high-quality materials. However, from time to time, from high mileage or simply improper operation of the car, this part can fail. You need to change it - MANDATORY, otherwise you can provoke a big accident.

Causes of failure

To be honest, the bearing is a very strong part of the hub. And to "kill" him you need to try! Most likely, all kinds of racks, rubber bushings and other attachments will fail, but if you “try” you can also disable this element.

1) high mileage . No matter how trite it may sound, but the high mileage of the car wears out all the components, and the bearing is no exception. This is the main cause of the malfunction, the rest are secondary. After about 70 - 120,000 kilometers, different manufacturers have different ways. You will hear a characteristic crunch. He says that this part needs to be changed.

2) Loss of tightness . The bearing has a little grease, which is covered with special casings made of rubber or plastic. If they are destroyed, then the lubricant comes out and wear becomes much greater. After a couple of thousand kilometers, you can hear a characteristic hum, which indicates a malfunction.

3) Sloppy driving . If you constantly fly into holes at high speeds, this will also wear out this knot a little. Although, as I wrote above, other suspension elements will fail faster.

4) Wrong pressing . This is a secondary reason; during repairs, a new bearing may be pressed incorrectly, for example, obliquely. Thus, when driving, it will not stand correctly, which will wear it out quite quickly, after about a couple - three thousand kilometers it will again need to be changed.

5) If too tight . This happened especially on our domestic cars, the bearing was overtightened during replacement, so it heated up more than usual, which also helps to reduce the resource and subsequent breakdown. So you need to take into account the twisting force, usually it is indicated in the instructions.

These are all the main reasons, however, as you can see, the last two are the “crooked hands” of a car service. So we change only at proven stations that give a guarantee for work. Sometimes it is more profitable to look at the official stations.

Breakage symptoms

Here is the most interesting thing - how to determine the malfunction, there are several one hundred percent methods.

1) "Dry" crunch . When a wheel bearing fails, it makes a sort of crunching sound when driving. These are rolled spherical elements. They broke the clip in which they were and now they are not evenly spaced. You will not confuse this sound with anything, believe me, this sound is perfectly heard in the cabin. This is the very first symptom - as such a sound appeared, we immediately go to the service station.

2) Vibration . If the bearing is already well worn, then vibration should appear, both in the steering wheel and in the body. This suggests that the spherical elements have already worn out the bearing race well, a little more and a “wedge” may come. Change urgently.

3) The car pulls to the side . It is also possible that the part with the defective element does not work normally - so to speak, it stalls a little, and therefore the car will pull in one direction or another, as with an incorrect one.

What happens if you don't change

Many motorists ride with faulty wheel bearings, and even accelerate to 100 or more kilometers per hour - guys, this is very dangerous, remember this is the connecting element of the wheel, which is responsible for its rotation. If it is broken, then at any moment it can jam. And this is a sharp stop of one of the front wheels. Now imagine if you have a speed of 100 km / h - at such a speed you just fly out to the side of the road, this is at best, but you can also fly into the “oncoming lane”, and here it’s not far from the accident. There have been times when cars have overturned. So guys, the hub bearing is very dangerous, if you don’t want to change it, drive at low speeds, up to 40 km / h, otherwise everything can end very badly.

We determine the malfunction ourselves (at home)

In general, in addition to the crunch that you will constantly hear when driving. You can identify by the signs yourself literally near the house.

1) We put the car on a flat, preferably paved area.

2) You need to check the play on the vertical axis. To do this, we take the wheel at the top point and try our best to swing it. If you hear clicks and there is play, then this is definitely a “hub”.

3) To be sure, you can jack up the wheel and rotate it. If a crunch is heard - a malfunction.

4) There is another method (only works on front-wheel drive), but it is advisable to do it on a lift. We need to raise the car, start it, turn on the gear and accelerate the wheels, then turn off the engine and listen. The side that will make noise, crunch and vibrate is faulty.

Now a small video version of the article

About replacement

What I want to say is to change the bearing correctly, it is quite difficult to do it yourself. You need at least a couple of pullers, as well as knowledge of the car's suspension. No wonder many automakers change the entire wheel hub.

When replacing it is important:

1) The bearing can be pressed in only with special even clips (it is ideal to use the housing from the old one). Pressing with "rolling bodies" is not allowed.

2) Avoid pressing with sharp tools, which may damage the O-ring, which will then lead to grease leakage.

Those car owners who, taking care of their "iron horse", try to regularly diagnose its various components and parts, often ask themselves: how to determine the malfunction of a wheel bearing? It was to him that it was decided to dedicate today's article.

Signs of a failing wheel bearing.

I would like to immediately warn all those who hope to read the universal wheel bearing diagnostic instructions - you will not find it here, or rather you will find it, but not in the form in which you wanted.

The fact is that the main way to determine a faulty bearing is while driving by ear, therefore, it is quite possible that you yourself, without suspecting it, have long diagnosed the named node.

Doubt? Then remember how your car has been behaving lately on the road: have you been alarmed by anything? Were there any strange body vibrations? Was there some kind of incomprehensible rumble (or crunch) heard - another, not the same, then the rubber emits when moving, but louder and more unpleasant, somewhat reminiscent of the sound of an airplane taking off. Have you noticed anything like this? So, most likely, everything is in order with the wheel bearings in your car. But let's not rush to conclusions, let's check everything again.

1. Choose a road that is free from traffic.
2. Accelerate the car on it to 40-60 km per hour.
3. Now, as if drawing a snake with the trajectory of your movement, alternately turn the steering wheel left and right - slightly, an amplitude of 20 degrees will be enough.
4. Listen for an unusual hum that accompanies you. If it accompanies, note when it intensifies, when turning right or left. In the first case, the left front bearing will be faulty, in the latter, the right front bearing.

How to determine the malfunction of the wheel bearing with your own hands?

At service stations for diagnosing wheel bearings, there are special devices that, through vibration monitoring, easily diagnose the condition and degree of wear of bearings.

However, not every one of us pays money for the fact that his wheel is simply fairly spun and shaken. We can do it ourselves.

1. Lightly jack up the car so that the wheel being checked, and preferably two at once (front or rear), are in limbo.
2. With one hand, take the wheel at the extreme top point, with the other - at the extreme bottom.
3. Now try to alternately tilt these points towards you and away from you. With a faulty wheel bearing, you will be good at this - a "healthy" bearing will not allow this.
4. If we are talking not just about the wheels, but about the front drive wheels, then they are checked not only for vertical deviation, but also for horizontal. To do this, the hands are moved to the extreme side points and alternately move their hands - towards themselves and away from themselves. The resulting noise is most often a sign of a faulty bearing, although it is quite possible that the problem is not in it, but in the steering rack.

Video.

The hub is the main link between the car body and the road through the wheel, and it is she who experiences the greatest loads, both in motion and at rest.

At the same time, not only the driving and speed characteristics of the car, but also safety depend on the serviceability of the hub.

Causes of wheel hub failure

If you do not repair or replace the failed hub in time, then it is likely you could get into a serious accident. - either due to wheel jamming at speed, or due to separation of the disk from the shaft.

Besides, defective hub gets very hot , and thus has a negative impact on the normal operation of the brake system of the wheel.

The hub never fails at the same time , if there was no strong blow from driving at speed into a pit, curb or bump. It is destroyed gradually, and usually its malfunction is accompanied by an unpleasant sound, vibration of the body, sensations of rolling and weak jolts.

The main causes of wheel hub failures are:

• Rough driving on rough roads.
• Car overload.
• Repeated falling under the "belly" into the mud slurry or sand.
• Aggressive driving with sudden braking and acceleration, the so-called "drifting".

Depending on the above, the hub housing may be deformed, the outer or inner rim of the bearing may split, the lubricant may “dry”, as a result of sand, moisture and dirt getting inside the rotating parts.

Very rarely, rollers or bearing balls are destroyed. , the causes of breakdowns of which, rather, depend not on the quality of the ride, but on factory defects.

All these faults at the initial stage it is very difficult and almost impossible to determine without special diagnostic equipment until a large wheel play is detected, or a characteristic sound appears, reminiscent of the rumble of an aircraft, and sometimes accompanied by a crunch and rattle.

How to identify a faulty wheel hub?

1. The easiest and most reliable way to identify a broken hub is to foot tapping on tires . If any of the tires staggers, there is excessive play, then the hub is probably out of order. Moreover, the backlash can be found long before the appearance of extraneous sounds that are not audible at low speeds, or are similar to the noise of the tread on asphalt.
2. Another way to determine that a hub needs replacement is − aurally, but this is possible only when the wear of the hub - or rather, the ball bearings in them - has reached a critical point, and the operation of the car has already become dangerous.
   • Front wheel hub failure , thanks to the steering system, it is quite easy to determine. To do this, you need to accelerate to a speed when the rumble begins to appear (usually 40-60 km / h and above), and wiggle a little. If the sound increases when turning to the right, then the left bearing “flew off”, if vice versa, then the right one ().
   • Determine the faulty hub on the rear wheels a little more difficult. It happens that it buzzes on one side, and the breakdown, in fact, turns out to be on the other. Therefore, in order to accurately identify a failed part, it is necessary to raise the stern of the machine. Then, on weight, rotate and shake the wheel in one direction and the other. If you feel play and vibration of the wheel, and sometimes crackles and crunches are heard, then the hub is out of order.
3. Finally, the third recommended method. Without certain skills and the appropriate tools, replacing the hub on your own will not work. At the slightest suspicion of extraneous sounds coming from the area of ​​​​a wheel, or the detection of play, immediately contact a specialized car service .

If you once heard some strange and suspicious rumble during a trip, then most likely you will have to check the wheel bearings. Such noises will undoubtedly cause concern to any conscientious driver, because inaction can be much more expensive. As already mentioned, the problem may be in the wheel bearings. It is because of their wear that various kinds of noise can appear, which must be urgently disposed of.

Rear wheel bearing functions

The hub is a very important part of any car. It has a hole that is created in order to fit the part onto the shaft or axle. The main function of the hub is to transmit torque from the crankshaft to the wheel, due to which the latter rotates, that is, the car moves. The wheel bearing plays an equally important role in the running gear of the car. It is available as a single row or double row ball bearing. They are linked together so that all safety precautions while riding are observed. Therefore, it is clear that any bearing failure is fraught with the fact that driving a car becomes unsafe.

Such a part has a special look, since it is the wheel bearings that are responsible for the reliable fixation of various nodes, but at the same time they can still rotate. The most important function, both rear and front, is to ensure reliable fixation and smooth rotation of the wheels.

The difference between front and rear hub bearings is only in design, but the functions performed are completely the same. The rear hub of the independent suspension is designed in much the same way as the front hubs, but the only difference will be in the steering knuckle. The rear wheels, depending on the design of the chassis, may have the following types of bearings:

1) Radial ball or roller in case of dependent suspension;

2) Conical in case of independent suspension.

Any type of rear hub bearing is subject to wear, and the reasons can be very different.

Rear wheel bearing problems

The main problem that can occur with rear wheel bearings is wear. There are several prerequisites for such a phenomenon, and they are very different - excessive load, low sealing efficiency, too small a gap due to a large interference fit.

A third of a car's bearings are damaged due to the normal fatigue process. Another third breaks due to improper or poor-quality lubrication. The rest of the bearings fail due to contamination, improper operation or incorrect installation. The specifics of the operation of machines is such that it allows us to identify several reasons why rear wheel bearings can fail and fail:

1) Poor lubrication of nodes. Lubricants can "degrade" due to excessive heat in the bearings, damaged seals, use of the wrong oil, or poor quality material to lubricate the wheel bearing assembly.

2) Bad seals. A similar problem is fraught with water and dirt getting into the bearings, as a result of which an abrasive mixture is formed.

3) Natural wear and tear. The first signs of fatigue damage depend on the magnitude of the load, the speed of the element, the purity of the lubricant and the effectiveness of its application. Wear can appear and develop due to variable shifts in the upper layers of the raceways, causing cracks to appear that go towards the surface. The rolling elements roll over cracks, which causes chipping of metal particles from which the bearing is made. Initially, this process, which is called "peeling" or "chipping", practically does not appear. But "peeling" is constantly developing and intensifying due to edge stresses, as well as due to the presence of wear products that are applied by the lubricant.

The process of fatigue “peeling” of bearing elements develops rather slowly, and is accompanied by an increase in the level of vibration and noise during operation. It is thanks to these signs that you can notice a similar problem and replace the bearings in time before they are completely destroyed. Keep in mind that due to too much lubricant in relation to the amount of surface roughness, almost no damage occurs. But due to the excessive load that falls on the bearing, after some time, quite natural fatigue failure will begin to develop.

How to check rear wheel bearing

It has already been said earlier that the presence of a faulty bearing can be determined by the excess noise that appears while driving. You can more accurately determine the state of the rear wheel bearings by turning to the right and left. When turning left, body roll is transferred to the right side. That is, the load is transferred from the left wheel to the right and vice versa. If at a speed of 10-15 km / h you turn the steering wheel sharply to the left, after which this extraneous noise disappears, it means that the noise comes from the left wheel, or rather, from its hub bearing. If the noise disappears when turning to the right, then you will have to change the bearing on the right wheel.

In order to carry out a more accurate diagnosis, you need to raise the car using a lift or jack. After that, start the engine, "accelerate" the car to a speed of 70-80 km / h in fourth gear, depress the clutch and turn off the gear. After that, you will need to determine by ear which wheel the noise is coming from. If the wheel is not driving, then you can spin it with your hands.

After the wheel stops, you need to take hold of the upper part with one hand, and the lower part with the other. Try to swing the wheel in a vertical plane. If there is even the slightest play, then be sure that the bearing will have to be changed. Similarly, try to loosen the wheel in a horizontal plane. To do this, you need to take the wheel by the left and right parts, and then try to swing it.

It happens that the backlash appears due to malfunctions of the suspension elements or due to the wear of the steering system. Ask someone to press the brake pedal with force, and at this moment try to swing the wheel vertically. If the backlash has not disappeared, then you need to look for the cause in. If the play still disappeared, then the reason is probably in the wheel bearing.

Remember one principle - if the wheel bearing is in good condition, then there should be no play. After you find out what the reason is, you can drive the car for service to specialists or replace the bearing yourself. When you work, be sure to keep clean, be sure to set the gap during installation of the tapered type bearing, and it is also advisable not to use sharp tools that can damage the seals.

To maximize the life of bearings, you must strictly follow the rules of installation and maintenance. The operating time of these parts also depends on the rule for choosing the element itself and on using the right tool for its installation. Never drop the bearing into mud or water, it must be properly lubricated and installed. Please observe the following guidelines during installation:

1) Take the bearing out of the package right before installation.

2) Keep it clean: cover the parts of the car that the bearing will be placed on, cover with a film, wax paper or a clean, dry cloth a new bearing that you have not yet installed.

3) Do not install bearings near machines that cut metal, or near devices that create pollution.

4) Do not hit the bearing.

5) Use a special sleeve to press in the bearing.

6) Choose the right lubricant. Apply it in the right amount. Lubricate bearings promptly.

7) Use special hydraulic or heating tools.

Rolling bearings are widely used in machine mechanisms, even in the most difficult conditions they are distinguished by a high degree of reliability. Premature failures are extremely rare. Failures of rolling bearings are primarily noticeable by the unusual behavior of the bearing during operation.

When examining damaged bearings, all sorts of signs can be identified.

As a rule, only a visual inspection of the bearing is not enough to determine the cause of the failure; including the condition of adjacent parts, lubrication and seals, as well as operating conditions.

Systematic actions in the investigation of a malfunction facilitate the search for its causes.

Causes of malfunctions

The service life of wheel bearings is calculated on average for a run of up to 1,000,000 km. However, the real picture is very different from the calculated one. Some unnatural conditions can lead to premature failure of the wheel bearing and shorten its life.

– In 70% of cases, the cause of the failure is improper lubrication: excessive, insufficient or inappropriate lubrication.

– In 18% of cases, it is contamination: moisture or solid material gets inside the bearing. Therefore, seals are important, as if the seals are damaged, grease can escape and contaminants can get inside.

– In 10% of cases, the cause is incorrect installation: excessive force, overheating, incorrect adjustment and gap, too tight conical bushing, etc.

Worn or damaged wheel bearings or hubs are a hazard to your customers. At the very least, this can lead to an untimely and costly breakdown on the road.

It is best to replace the wheel bearings or hub assembly before they fail. But how can you know when it should be done?

The chart (fig. 1), created from millions of data on bearing replacement statistics, shows that the actual mileage

car, when you probably need to replace the bearings - is between 130,000 and 190,000 km.

Therefore, for maximum safety and reliability, bearing manufacturers recommend that you check your wheel bearings every time you change your brake pads, regardless of the age of the vehicle. And you should always pay attention to the first signs of bearing wear, such as noise when driving or unusual braking when turning the steering wheel.

Common Forms of Rolling Bearing Faults

– Overheating.

– Destruction of the outer ring.

- Skew.

- Too tight fit.

– Material fatigue.

– Dents in the rolling elements.

– Pollution.

– Incorrect lubrication.

– Corrosion.

– Damage to the edges of the bearing.

- Badass.

– Wrong load vector.

Experience has shown that most "defective" parts returned to distributors are actually not. Usually, their premature failure is due to other factors, from damage caused by adjacent components and systems, failures in their operation, to improper installation.

Let's try to understand these damages and the reasons that caused them.

When diagnosing problems with automotive components, look for signs such as scratches, dents, streaks, cracks, discoloration, overly smooth surfaces, etc. In many cases, these signs will immediately help to establish the cause of the failure of the part. When diagnosing malfunctions in the operating mode of the car, you should pay attention to noise. A bearing in good condition makes a smooth, almost indistinguishable sound. If you hear a crunch, rattle or other unusual sound, then you need to establish its cause.

Unusual bearing behavior during operation indicates a failure (table 1). Bearing failures are usually manifested by deterioration in performance. Sudden failure is less common, such as improper installation or lack of lubrication, resulting in rapid failure. Depending on the operating conditions, it may take some time from the moment of damage to the actual failure of the bearing, under certain circumstances - several months.

Operating behavior	Possible reasons	Result
Uneven stroke	Damage to rings and rolling elements	Increasing wheel vibration; increased backlash; vibrations in the steering mechanism
	Pollution	Rising vibration
	Too much bearing clearance	Increasing blows
Unusual noise during rotation (hum or whistle)	Too little clearance in the bearing
Unusual noise during rotation (rumble or uneven knocking)	Too much clearance in the bearing; rolling surface damage; pollution; improper lubrication
Gradual change in noise during rotation	Changing the clearance in the bearing due to temperature effects; raceway damage

Diagnosis of malfunction of wheel bearings

"Oval deformation"

1. Remove the wheel bearing from the mounting hole.
2. Check if there is a dark spot on two opposite sides of the top surface of the outer ring. Make sure both surfaces that are at 90° to the dark spots are undamaged. If this is the case, then the mounting hole is deformed and the steering knuckle needs to be replaced.
3. To make sure there is no wear in the outer ring raceways, take the wheel bearing apart. In this case, first remove the seal (for example, with special pliers), and then dismantle the assembly consisting of the outer ring, inner ring, cage and balls.
4. Clean the raceways of the outer ring and check for any "holes" that match the location of the dark spots on the outer side of the outer ring. The presence of such "shells" indicates "oval deformation" of the steering knuckle.

This defect is one of the most common, therefore, in the process of diagnostics and repair, we recommend using the recommendations presented in Table 2.

Problem	Cause	elimination
After installation and start of operation, the bearing makes a loud noise (hum).	One of the inner rings is damaged: 1. Inconsistency of the tightening torque with the nominal value.	Replace hub and bearing.
	2. Installing inner race on hub misaligned - wrong tool - wedge or bushing between driver and contact side of bearing ring not parallel.	Replace entire wheel bearing.
	3. Too much oval deformation of the mounting hole, due to which the radial clearance of the wheel bearing is severely limited in narrow zones of “oval deformation”.
	4. The landing hole in the steering knuckle is damaged.
	5. Deep scratches or burrs caused by improper dismantling, both on the contact surface of the hub and on the wheel bearing itself.	Repair small defects in the hub (e.g. by polishing) or replace the hub and bearing.
The wheel bearing starts to make noise after a certain mileage (500 - 3000 km)	The knuckle mounting hole has a medium “oval deformation” sufficient to limit the radial clearance in the bearing and cause the damage described in the previous paragraph.	Replace steering knuckle and wheel bearing.
Excessive heat generation at the beginning of operation	1. The axial clearance in the bearing between the hub and the steering knuckle is very limited. Incorrect positioning or mounting.	Check the positioning of the steering knuckle and hub, repeat if necessary.
	2. Due to improper mounting of the wheel bearing in the mounting hole (there are no thrust rings in the mounting sockets), the axial displacement of the bearing and the hub gradually occurs. The rotating hub touches the fixed bearing housing. Due to the high friction, the temperature in the area of ​​the wheel bearing rises. This burns out the lubricant, which leads to bearing failure.	Remove the wheel bearing and check the presence of thrust rings. Replace the wheel bearing if necessary.

Raceway damage

This can happen due to several reasons:

Impact on the inner ring during bearing mounting (Fig. 2).

Ingress of a foreign body into the bearing (Fig. 3).

The entry of a foreign body into the bearing, which caused wear and subsequent chipping of the ring surface (Fig. 4).

Exceeding the static load capacity of the bearing.

Falling bearing or mounted assembly.

As a result, dents in the rolling elements appear as depressions in the raceways, which increase the vibration of the bearing (hum). Severe dents can lead to premature bearing failure.

In order to avoid such a problem, the mechanic must mount and dismantle the bearing only with a special tool, which we will discuss later. And apply the pressing force on the tight-fitting ring.

Darkening of the surface of the outer ring of the bearing (Fig. 5)

Full text of the article: see "Archive" of the magazine "Avtomaster" No. 1-2 2008 Sergey Uktusov, full version with drawings.