Uneven pad wear. let's look at the front and rear

Uneven wear on a car's pads sometimes occurs on cars with both drum and disc brakes. As a rule, the reasons for this phenomenon are typical - improper operation of the guides, the piston is not fully retracted, damage to the protective rubber seal, rust on the caliper bracket and some others. Usually, eliminating the causes of uneven brake pad wear does not take much effort.

Most often, a lot of time and attention is spent on diagnosis and directly searching for the cause. Therefore, we will consider a number of cases, both general and specific, where it is worth looking for the cause of uneven wear of brake pads.

Uneven wear of the vehicle on one axis

The true cause of uneven wear of brake parts can be determined using diagnostics, which is carried out in a professional car service center.

The main problem is the uneven wear of the inner and outer brake pads of disc brakes, which occurs for several reasons:

• the piston moves with deviations from the design stroke - it does not retract completely due to damage to the rubber seal;
• the appearance of rust on the caliper bracket, leading to “sticking” of the brake caliper;
• The guide seal is damaged (dirt gets in), which prevents the vehicle from returning to its normal position after the end of braking.

Deterioration in the performance of one or another vehicle on one wheel is only one of the reasons for incorrect braking. Another fairly common situation is uneven wear of the brake pads on one axle: the right and left front (rear) wheels.

More intense wear on one of the wheels may be caused by:

• exit from standing one of the guides;
• problems with hydraulics that prevent the TC from being pressed with the required force;
• damage to the hose;
• ABS malfunctions;
• disc deformations.

Sometimes a situation arises when the rear brake pads, contrary to generally accepted practice, wear out faster than the front ones. In this case, with almost one hundred percent probability, the problem is that the parking brake cable is overtightened or jammed due to contamination or improper adjustment.

Uneven wear of the rear brake pads working with the drums is often associated with jamming of one of the cylinders, resulting in asynchronous braking of the wheels, accompanied by a skid of the car.

Among the most common reasons for the development of such a problem are the following malfunctions:

• Excessive wear of the caliper piston;
• Problems with guides;
• Violation of the integrity of the anthers;
• Souring of the caliper.

When particles of debris and dirt, moisture and other substances get on the guides, chips and scratches form in them. As a rule, this leads to jamming of the guides, which causes uneven wear of the pads in the future. To prevent this from happening, the guides must be lubricated with a special lubricant.

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Torn anthers usually lead to failure of the brake system very quickly. Sometimes a car doesn’t last even a month without breaking down. To prevent this unpleasant incident from happening, the anthers must be periodically inspected and replaced. Otherwise, it will not be possible to do without expensive repairs of brake system elements.

Wedge wear

We are talking about partial abrasion of the surface of the linings. This phenomenon is most often associated with errors made during brake assembly or other types of maintenance. As a result, the clamping force is unevenly distributed, the maximum pressure falls only on a small area of ​​the pad. In this case, it is necessary to replace the guides.

It is important to understand that not all cases of uneven wedge-shaped pad wear are abnormal. This may be due to the use of multi-piston calipers.

But at the same time, it is also important to remember that normally wedge-shaped wear of the pads is not significant. If the abrasion is too pronounced, it is necessary to look for other reasons.

Heading

: Technical science

: 17.05.2016 2016-05-17

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1933 times

Bibliographic description:

Klishchenko F. Yu., Poluektov M. V. Causes and consequences of uneven wear of car brake pads // Young scientist. 2022. No. 10. pp. 234-236. URL https://moluch.ru/archive/114/30187/ (access date: 08/02/2019).

The article discusses the possible causes and consequences of uneven wear of the internal and external brake pads, one brake mechanism.

Key words: uneven wear, brake pads, disc brakes.

When carrying out maintenance and checking the condition of the brake system, the phenomenon of uneven wear of the brake pads of one brake mechanism is often observed. Statistics show that in some cases the internal brake pad wears out much faster than the external one.

Human factor

The most common reason for brake pads to wear out too quickly is human error. The pads wear out quickly on cars driven by drivers who use both feet (the left one is on the brake pedal, the right one is on the accelerator) when operating the car. The left foot of such drivers is constantly in contact with the brake pedal.

Any pressure on the pedal activates the brake mechanisms. Even a small force applied to the edge of the pedal causes the pads to contact the brake disc on a moving vehicle. This contributes to rapid wear of the brake pads.

This process is also accompanied by overheating of the brake discs, which can be easily identified by bluish marks of tarnish on the surface of the disc.

Uneven wear of pairs of pads on one axis

If the front pads wear unevenly, there may be several reasons. Most often the problem occurs due to “fingers”

Since the caliper runs on guides, it is important that they are well lubricated. If the lubricant has dried out, the seal has been lost or failed, the operation of the system is disrupted, which leads to uneven wear of the pads

To avoid this, change the seals on time, check the guides for foreign impurities and contaminants, and lubricate them with special compounds. You cannot use pad lubricant for the “fingers” - they have different performance characteristics. The lubricant on the guides must be special.

The second common cause of malfunction is damage to the brake hose. It is located in such a way that it is regularly exposed to external influences, for example, impacts from stones flying from under the wheels. As a result, the tightness of the brake system decreases, its operation is disrupted, and the intensity of pressing the pad to the disc during braking changes. Plus, if the hose is damaged, brake fluid leaks. The hose needs to be changed.

Problems with hydraulics also affect natural wear and tear - braking occurs abnormally. Water lock is a common problem. The piston stops moving as expected, the pads are not pressed against the disc with the proper force, and the load is distributed unevenly.

An additional symptom of a hydraulic lock is that the car pulls to the side after pressing the brake pedal. To fix the problem, you need to take the car to a service station.

Unusual wear can occur when the brake disc is warped. This most often happens during heavy braking, when the system cools sharply (for example, a car drives through a puddle of cold water). A sharp temperature change - and the disk becomes deformed. This usually only happens on one side.

As a result of imbalance and uneven pressure, the pads also wear differently. An additional symptom of this problem is a wobbly steering wheel. The situation can be corrected by replacing the disk and related parts.

Wedging the guide supports

This problem occurs in several different stages of difficulty. Some people's calipers jam so much that the brakes continue to work quite intensely even when they are not required to do so. For others, the pads, although effortlessly, are still in constant contact with the discs. It is clear that all this leads to chronic heating of the brake system parts, and a hum will be heard when pressing the pedal under normal load.

In most cases, jamming of guide supports can be easily “treated” with your own hands. To do this you need:

1. Make sure the anthers are intact.
2. Carefully inspect the guides for clogging or corrosion.
3. If the last two are present, clean them.
4. Lubricate the guides.

As a matter of fact, due to the not entirely comfortable conditions in which these parts of the brake system are constantly located, jamming is a common cause of buzzing. The anthers collapse, crack, and slide off. The lubricant is washed out with water. Dust and dirt accumulate on the “mirror” of the guides. Next comes corrosion and the corresponding consequences. Therefore, if the repair is successful in this direction, do not forget to periodically check the guides for the integrity of the anthers and the presence of lubricant. After all, problems can be even worse than some kind of brake noise.

Attention! Very often, when manipulating the brakes, car enthusiasts use the well-known WD-40 or analogues. Yes, it helps a lot in developing soured parts

But it also “loves” to get on the brake discs, which subsequently completely deprives the car of brakes for some time.

What determines brake pad wear?

1. Operation process.

Under normal operating conditions, brake system pads wear out after 15-30 thousand kilometers or more. However, these are not reference values. Wear can occur later or earlier, especially if the emergency braking is abused. Here a lot depends on the driving style and the quality of the pads themselves.

2. Manufacturer, model of the brake system and quality of friction linings.

Each specific case has its own estimated wear time. They are usually indicated by the manufacturer on the part itself.

3. Technical faults.

The reason for uneven wear of brake pads, as well as shortened service life, is a malfunction of the brake cylinders, which also leads to damage to the brake disc.

Torn anthers

Another reason that leads to uneven wear of brake pads and problems in the operation of the brake system as a whole is anthers. The amount of dirt, sand, stones and other debris that gets onto the mechanical parts of the car’s braking system depends on how solid they are.

If the boot is torn, the brake system does not last for a month without breaking down. Because of this, it is important to monitor the integrity of the boots, and if they are damaged, replace them immediately to avoid damage to more expensive elements of the brake system.

Drum pad wear

Finally, a little about the drum mechanisms that are used on the rear axle. There are cases when the pads of these mechanisms wear out faster than disc ones.

In addition to their main function, drum mechanisms are also an integral part of the parking brake. And it is the handbrake that usually causes accelerated wear.

Moreover, because of it, they can be intensively erased both on both mechanisms at once, and on just one.

If accelerated wear is observed on two mechanisms, you should check the condition of the handbrake drive.

An overtightened cable causes the lever installed inside the mechanism to constantly keep the pads in a relaxed state, and they come into contact with the drum, rubbing against it.

If there is wear on the elements on only one side, you need to check the adjustment of the release mechanism. If this mechanism is not adjusted correctly, it will press them against the drum.

Well, don’t forget that the cause of wear on one side can be problems with the drive - airing of the line, its blockage, damage to the cuffs of the working cylinder.

Why do the rear pads wear out faster than the front ones?

According to the laws of physics, everything should be the other way around - when braking, the maximum load falls on the front part of the car, since the rear part seems to roll over it. Therefore, the front brakes are subject to much more stress than the rear brakes. This is due to the rare replacement of the rear elements of the brake system - for one replacement of the rear pads there are 2-3 replacements of the front ones.

But exactly the opposite happens.

If the rear ones are worn out faster than the front ones, there can be two reasons - the parking brake is incorrectly adjusted (the belt is too tight) or the cable entry point has become heavily contaminated, causing the cable to jam.

So we talked about the main reasons for atypical pad wear. Timely maintenance, installation of high-quality spare parts and regular diagnostics will eliminate the typical problems of uneven wear of brake system components. But if you have already encountered a problem, do not delay repairs - otherwise the problems will grow like a snowball!

Often, car owners, when carrying out maintenance of the brake system, notice that uneven wear of the pads occurs.

Moreover, this problem can be expressed in different ways - only one specific element is erased, wear can be more severe only on a certain mechanism (right or left, front or rear).

In general, there are a lot of variations, but in any case, this signals a problem in the operation of the brake or drive, which must be eliminated.

Main signs of brake pad wear

Let's look at how to determine brake pad wear:

1. Strange behavior of the braking system.

If you begin to notice that the braking has become too harsh or weak, and the brake pedal drops lower than usual, then this is a signal coming from a worn-out pad.

2. Beating during hard braking.

The noise and sensation of beating indicate one of two possible causes. The first is pad wear. The noise occurs due to chips and cracks on the part that appear as a result of uneven abrasion of the surface of the product, the service life of which is already nearing the end, and the part itself requires urgent replacement. The second possible reason is brake disc wear. In this case, it is necessary to replace the spare part or sharpen it.

3. Metal shavings on rims.

This method of checking is only possible if you do not have ventilated brakes or alloy wheels. The check is as follows: under the wheel cap, you need to check for metal inclusions in the brake dust. If they are present, this indicates damage to the lining, causing the disc to be scratched by the pad. If they are absent (the color is charcoal and uniform), then everything is in order with the overlay.

4. Reduced brake fluid level in the reservoir.

Indicates possible problems with the brake pads or discs.

5. Sensor signal (if available).

The sensor is mounted in the friction lining. Wearing the pads to a minimum causes the circuit to close, which triggers the activation of a signal about the need to replace them on the car control panel. However, you should not completely rely on the sensor, because... the wire may corrode due to contact with water, which will disable the alarm system.

One of the most effective ways to detect faults is to diagnose the brake system in a car service due to the fact that not all problems are clearly visible. In addition, the level of pad wear and the time until it needs to be replaced is best determined by expert analysis. Here you can select and install a replacement for a worn-out part on favorable terms.

Braking of a car occurs as a result of friction between the brake pads of its wheels and the discs. This happens at the moment when the driver presses the corresponding pedal

Often we don’t even think about their condition, and only when problems begin do we pay attention to them. Over time, these elements wear out, this is quite normal, because the pad is specially made of a softer material than the disc so that wear is present on it

However, such “erasing” does not bring anything good; you need to clearly understand and “see” the signs of the main elements of braking, otherwise traffic safety decreases...

What to do if you’ve already “got it”?

My verdict is clear - remove the damaged disks, throw them in the nearest trash can, buy and install new ones. But let me explain why I think so. Many at this point thought: “What a fool, you can save money and just sharpen the curved discs that have begun to “beat!” No matter how it is.

Grooving brake discs without removing them from the car. Quick and easy, as long as you leave the station quickly and leave the money. It is advisable to come again later. However, this is relevant

The grooving machine can really maintain the flatness of the plane with an accuracy of 0.0005 mm, and the discs will indeed be almost perfectly flat after grooving. But do not forget that they are most often driven by overheating, albeit due to various technical reasons. Brake discs are made of cast iron, which does not like overheating and quickly changes its properties as a result. The grooving will remove the surface layer of the metal, but literally 1-2 good braking times and the discs can again be removed and taken for grooving. Is it worth it?

A groove can also remove grooves and correct wear on one side. But there is another question - how much metal will have to be “cut off” and how much of it will remain after cutting? How many kilometers can you drive after such a repair? Maybe it’s better not to try to save money?

In addition, if you have obviously low-quality disks installed, this is an excellent reason to change them. Yes, the pleasure is not cheap, but it is better to buy the experience in this way than to later get into a serious accident.

Problems with guides

As you know, when working, the caliper “walks” along guides, which are often called “fingers”. If dirt, moisture gets on them, they rust, chips, scratches or other mechanical damage appear on them, then a problem arises with their jamming. The problem is similar to the situation with caliper wear - the friction part on one side may be excessively compressed, which is why uneven wear of the pads will occur.

To prevent such a situation from arising, you should not only monitor the brake fluid and change it in a timely manner, but also be sure to lubricate them with a special lubricant when installing the pins

Please note that a common mistake is to use pad lubricant on the guides. This is wrong, there is a special lubricant for them with the necessary properties

Caliper wedge due to souring

Perhaps the last reason that is important to pay attention to in this article is caliper souring. It can occur due to various problems - from drying out of the lubricant on the guides when the car is idle for a long time to water ingress or simply poor-quality workmanship of the part.

If the caliper becomes wedged due to souring (or any other reason), the brake system will not work properly, and uneven wear of the brake pads may occur.

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How to determine brake disc wear

Checking the wear of brake discs is not quite difficult; the main thing is to have a caliper or micrometer on hand, and if you don’t have such tools, then, as a last resort, you can use a ruler or a coin (more on this below). The thickness of the disc is measured at 5...8 points around the circle, and if it changes, it means that in addition to wear on the braking area, there is curvature or uneven abrasion. Therefore, it will be necessary not only to change it at the limit, but also to find out the reason due to which uneven wear of the brake disc occurs.

At the service, the thickness of the disks is measured with a special device - this is a caliper, only it has smaller dimensions, and also on its measuring lips there are special sides that allow you to cover the disk without resting against the side along the edge of the disk.

How is it checked?

In order to find out the degree of wear, it is best to dismantle the wheel, since the thickness of the disk cannot be measured otherwise, and if you need to check the wear of the rear brake drums, you will have to completely remove the entire brake mechanism. When carrying out further inspection, it is necessary to take into account that the discs wear out on both sides - external and internal. And not always evenly, so you need to find out the degree of wear of the disk on both sides of the disk, but more on that below.

Before checking, you definitely need to know information about the thickness of the new brake disc for a particular car. You can find it in the technical documentation or on the disk itself.

Brake disc wear limit

The value of the maximum permissible wear will depend on the initial size of the disc and the power of the car engine. Typically, the total wear of the entire disc for passenger cars is about 3...4 mm. And for specific planes (internal and external) about 1.5...2 mm. With such wear and tear, they need to be replaced. For brake discs consisting of one plane (usually installed on rear brakes), the procedure will be similar.

Checking the wear of brake discs involves checking the thickness of both planes of the disc, the size of the flange, and then comparing this data with the nominal value that a new disc should have, or recommended parameters. Also evaluate the general nature of abrasion of the working area of ​​the disk, namely, uniformity, the presence of grooves and cracks (the size of cracks should not be more than 0.01 mm).

During a routine inspection, it is necessary to look at the size of the excavation grooves and their structure. Small regular grooves are normal wear. It is recommended to replace discs paired with pads if there are deep irregular grooves. If the brake disc wears conically, it is necessary to change it and check the brake caliper. If the disc shows cracks or other corrosion and discoloration, it is usually due to thermal phenomena resulting from frequent and excessive changes in the temperature of the disc. They cause noise when braking and reduce braking efficiency. Therefore, it is also advisable to replace the disk and install better ones with improved heat dissipation.

Please note that when the disc wears around its circumference, a certain edge is formed (the pads do not rub on it). Therefore, when measuring, you need to measure the working surface. It is easier to do this with a micrometer, since its “clasping” working elements allow you not to touch it. If you use a caliper, you need to place some objects under its gauges, the thickness of which coincides with the wear of the pads (for example, pieces of tin, metal coins, etc.).

If the thickness of the disk as a whole or any of its planes is below the permissible value, the disk must be replaced with a new one. Do not use a worn brake disc!

When replacing a brake disc, you always need to change the brake pads, regardless of their wear and technical condition! Using old pads with a new disc is strictly prohibited!

If you don’t have a micrometer at hand, and it’s inconvenient to check with a caliper due to the presence of a side, then you can use a metal coin. For example, according to the official Central Bank of Russia, the thickness of a coin with a face value of 50 kopecks and 1 ruble is 1.50 mm. For other countries, relevant information can be found on the official websites of the central banks of the respective countries.

To check the thickness of the brake disc using a coin, you need to attach it to the working surface of the disc. In most cases, critical wear of one surface of the disk is within 1.5...2 mm. Using a caliper, you can thus find out the wear thickness of both one half of the disk and the total thickness of the entire disk. If the side is not worn out, you can measure directly from it.

The principle of operation of the brake mechanism and types of uneven wear

It is not easy to understand why brake pads wear unevenly if you do not have an idea of ​​the operation of the mechanism as a whole. The operating principle does not have complex elements. The entire mechanism is shown in the figure below.

It includes: a brake disc, above which a U-shaped caliper is installed, containing a working cylinder piston. The caliper holds two pads, between which the disc rotates. By pressing the brake pedal, the driver activates the hydraulic mechanism. The fluid in the system pushes out the piston, which presses the first pad against the disc. The counterforce moves the caliper along the guides, after which the second pad is pressed.

Drum brakes, which are installed on the rear wheels, work on a different principle. There are two pistons in the brake wheel cylinder. When you press the pedal, the pistons press the pads against the walls of the drum. The car slows down. By releasing the pedal, the driver starts the reverse process, in which the springs attract the elements to the center of the drum.

Features of operation

To begin with, we will briefly consider the principle of operation of the mechanisms, so that in the future it will be clearer why uneven wear occurs.

Disc brakes are becoming more common and many cars are being produced that have this type installed on all wheels.

The operating principle of these mechanisms is quite simple. Above the brake disc mounted on the hub is a U-shaped caliper.

Its design includes a working cylinder piston. There are two pads located between the caliper lugs and the disc.

When you press the brake pedal, the fluid squeezes out the piston, and it begins to press one pad.

In this case, a counteracting force appears, which forces the caliper to move along the guides. Due to this movement, the second pad is pressed.

Drum mechanisms are now used less and less and are installed only on the rear axle.

Here the principle of operation is even simpler: the working cylinder has two pistons, which, when exiting the cylinder, each press its own shoe against the drum.

It is worth noting that one type of uneven wear on brake pads is constantly present and is considered normal.

The point is that elements on the front axle wear out more intensively than on the rear axle.

And if you take a car that has drum brakes installed at the rear, the difference in wear rate is very significant.

The faster wear of the pads installed on the front axle is due to the fact that the load on them is higher, since when braking the mass of the car shifts forward.

As a result, they are the ones who do the main work, but because of this, their erasure is stronger.

Proof of this is the fact that the rear pads are changed two or even three times less often than the front ones.

Brake fluid as the root cause of uneven pad wear

Brake fluid is an important component of a vehicle's hydraulic brake system. It must be changed in a timely manner so that problems do not arise with the brake system components.

At the same time, it is important to use exactly the brake fluid that is suitable for your car, while many of its variations can be found on sale, classified according to the DOT system

As such, brake fluid does not affect uneven pad wear, but it does cause damage to parts that lead to the problem in question. Let's look at this issue in more detail below.

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What is the wear on brake discs?

Any car owner should know what wear of brake discs is acceptable, at which they can still be used safely, and what wear is already limiting, and it is worth changing the discs.

The fact is that if the maximum wear of the brake discs is exceeded, there is a possibility of an emergency situation. So, depending on the design of the brake system, the brake piston may either jam, or it may simply fall out of its seat. And if this happens at high speed, it is very dangerous!

Permissible wear of brake discs

So, what is the acceptable wear for brake discs? Each manufacturer prescribes brake disc wear standards. These parameters depend on the car engine power, size and type of brake discs. Wear limits will vary for different types of discs.

For example, the thickness of a new brake disc for the popular Chevrolet Aveo is 26 mm, and critical wear occurs when the corresponding value decreases to 23 mm. Accordingly, the permissible wear of the brake disc is 24 mm (one unit on each side). In turn, disc manufacturers apply information about the wear limit directly to the working surface of the disc.

This is done using one of two methods. The first is the direct inscription on the rim. For example, MIN. T.H. 4 mm. Another method is to mark a notch in the form of a notch on the end of the disk, but on the inside (so that the pad does not scratch against it). As practice shows, the second method is more convenient, since as wear increases to critical levels, the disc begins to brake jerkily, which will be clearly felt by the driver when braking.

The permissible wear of brake discs is considered to be such that it does not exceed 1-1.5 mm

, and reducing the thickness of the disk
by 2...3 mm
from the nominal thickness
will already be the limit!
As for drum brake discs, as they wear out, they do not decrease in size, but increase in their inner diameter. Therefore, in order to determine how much wear they have, you need to check the internal diameter and make sure that it does not exceed the permissible standards. The maximum permissible working diameter of the brake drum is stamped on its inner side. As a rule, it is 1-1.8 mm.

Many resources on the Internet and some car dealerships indicate that brake disc wear should not exceed 25%. In fact, wear is ALWAYS measured in absolute units, that is, in millimeters! As an example, we present a table similar to those given for various cars in their technical documentation.

Disc brakes

Disc brakes are most often found on mountain bikes, although recently, with the advent of budget models, they can be found even on road bikes, and they are finally being used on the road (braking on a carbon rim in the rain is even more fun).

Regardless of how many pistons you have, there are usually 2 pads in a disc brake, although there are all sorts of experiments, like the Magura MT7 with four pads.

To assess the degree of wear on disc brake pads, you will first have to remove them from the caliper; the title photo of this post once again confirms that it is better to inspect the pads when removed from the bicycle. Take a look at the photo below, it shows the difference between the worn and new pad.

You've probably noticed that the wear is also uneven; one part of the pad has worn out more. This happens with hydraulic brakes and may indicate that the piston is slightly distorted or the piston seal in the caliper is dirty. Before installing new pads, you will need to align the piston and lightly lubricate it. The best lubricant to use is not just any sprays or oils, but mineral fluid or DOT, depending on what is used in your brake. A couple of drops where the piston exits the caliper will be quite enough; the excess should be wiped off with a rag.

But let's get back to our pads. It's time to change them if the thickness of the working surface of the pad is less than 1 millimeter. Of course, such a block is “still good”, but don’t delay replacing it. If the abrasive wears off and the metal of the pads begins to rub against the brake disc, then most likely you will have to replace it too, or change the pads very often. Rotors with a damaged braking surface “eat up” the pads very quickly.

Severe wear on the caliper piston

Perhaps the most common cause of uneven pad wear. It often occurs precisely because of untimely replacement of brake fluid. As you know, brake fluid needs to be changed because it becomes saturated with moisture. The presence of moisture in it negatively affects the piston, which begins to rust from the inside and, as a result, does not work well.

When the driver presses the brake pedal, the piston compresses the brake pads. When you release the pedal, it should move away. But, if the piston is heavily rusted or worn, then when the pedal is released it may remain slightly (or significantly) pressed against the brake pad. Since there are two pistons on one axis, and one may be more worn than the other, the likelihood that they will both “jam” equally is extremely low. Hence it turns out that one pad wears out unnecessarily, but the second does not.

Please note that the first sign of such piston operation is a strong whistle and squeak during braking and acceleration.

Stages and features of diagnosis

The measuring stage of the test involves the use of a caliper, which will help make thickness measurements. At approximately 5-8 points, moving around the disk, measure the thickness. If it varies along the radius of the part, there are signs of curvature and uneven wear.

Check the information from the manufacturer to understand whether the wear limit has already reached or not. I cannot say which indicators are correct and which are not, since different discs have their own wear limits.

Then a visual inspection is carried out. The disc should be examined for cuts, chips, dents, scratches and other defects on its surfaces. If they are, the spare part will have to be replaced.

Do not forget about the rule of pairwise replacement on the same axis. That is, when the left front disc is changed, the front right one also changes at the same time.

If you want to assess the condition of the elements without removing the wheels, this can be done by checking while driving. With severe wear, characteristic signs appear:

• the car brakes jerkily;
• a grinding sound appears;
• there is a squeaking sound when you press the brake;
• other extraneous sounds are heard;
• the driver feels a beat on the steering wheel;
• the beating is also felt in the gas pedal;
• When the brake pedal is pressed, the braking system is locked.

I strongly do not recommend waiting for such symptoms to appear. It’s better to periodically do simple diagnostics in your garage through visual inspection and measurement. This is usually done every 10-15 thousand kilometers, if wear symptoms do not appear earlier.