Working condition brake pads essential for safe ride. Therefore, when buying a used car, you need to know how to check the health of these parts, as well as determine the need for a timely replacement.
What affects brake pad life?
The brake block has two components: the body; friction lining. The latter accounts for the main load during braking, so this part of the part is erased over time. According to the rules of control technical condition brake pads, they should be changed after 10 thousand km. run. But this is only an approximate indicator, since there are other factors that affect the service life:
- brake pad quality. Pressing technology and composition different manufacturers differ, which affects the maximum possible period of operation;
- character of driving. City driving and constant hard braking lead to premature wear of the pads;
- problems in the operation of the brake cylinders entail uneven wear of the brake pads and malfunctions in the brake disc.
Signs of brake pad wear
When choosing a used car, you need to pay attention to the signs of brake pad wear, which you can determine yourself:
- the handbrake is fixed in the far position. If the lever needs to be retracted very far, or the car on the handbrake moves down an inclined surface, this indicates wear. rear pads;
- too long braking distances;
- weak and inefficient braking at maximum pedal pressure;
- too sharp braking and the presence of a metal friction sound can also indicate severe wear. This means that the friction lining has worn off, and the pad body rubs against the disc;
- squealing of the car during a stop indicates wear of the friction lining. For this, an indicator is specially mounted. When the pad is significantly worn out, the indicator begins to cling to the brake disc, as a result of which unpleasant sound;
- vibration during hard braking. It occurs due to uneven wear of the brake pads;
- level reduction brake fluid;
- a dark coating on the wheel means that there is still a friction lining, but metal inclusions indicate a worn lining, since the pad body is already scratching the disc;
- if there is a brake pad sensor, the indicator on the control panel will light up when the minimum lining thickness is reached.
Brake pads must be changed when the friction lining is less than 5 mm. For greater confidence in the satisfactory condition of these parts, it is recommended to show the car to a specialist at the service station.
Recommendations for the operation and replacement of brake pads
To protect the brake pads from premature wear and to ensure their serviceability, the following recommendations should be followed:
- calm driving style, lack of frequent hard braking significantly increase the service life of the pads;
- replacement must be carried out either on the axle or on the entire vehicle. Replacement on one side only is unacceptable, as this will lead to serious problems with braking;
- be careful when driving with new pads. The first couple of tens of kilometers, the brakes will work worse, because they need time to get used;
- inspect the pads during the replacement of tires from summer to winter and vice versa;
- when changing pads, you also need to assess the condition and the need to replace discs and drums;
- carry out regular diagnostics of the condition of the car at the service station.
Careful inspection of brake pads before buying a used car, as well as their timely replacement keep you safe from danger while driving. Therefore, do not forget to periodically inspect the condition of the car, which guarantees you long term his service.
Pad linings play a huge role in the brake system. Failure to replace them promptly may result in complete failure brakes during emergency braking. The article outlines the main signs of wear brake pads.
Linings are tightly attached to the metal base of the brake pads - due to which the braking process takes place. The condition of the brake linings directly affects the safe braking of the car. Brake pads use friction force in their work. When the car brakes, this part interacts with a metal drum and absorbs kinetic energy vehicle. As a result, it is converted into thermal energy and dissipated in the air.
The main signs of brake pad wear are:
1. Most brake bars are equipped with an electronic or mechanical indicator. The panel displays the degree of wear of the pads and the need to replace them.2. An important indicator wear and tear is lining thickness. With a thickness of less than 5 mm, they definitely need to be changed. If this is not done, the piston brake cylinder will constantly appear from the anther. This will lead to the formation of rust on the piston mirror. After replacing the pads, rust will get on the sealing gland brake piston. As a result, a leak will appear from the cylinder. It will also need to be changed. In addition, you will need to bleed the brakes.
3. Noises, knocks, vibrations when braking also indicates wear on the linings.
4. For rear pads, the actual pad wear indicator is increased lever travel hand brake . This requires a mandatory check of the pads.
5. Squealing when stopping the car means that the friction material of the pads has worn down to the metal itself.
6. Decreased brake fluid level.
7. Vibration around the wheels indicates uneven wear. This may result in the need to replace the wheel drum or discs.
8. Unusual brake pedal behavior.
9. Appearance brake dust on discs.
10. Increase in stopping distance and time to stop the car. This indicator indicates the complete or uneven wear of the linings.
Service life of brake pads
→ Wear of the brake shoe lining can also be determined by examining the condition of the brakes through a special window in the drum. It is the regular inspection of the brake linings that allows you to understand the need to replace them. You can also correctly determine the state of the friction layer using a caliper.→ Manufacturers usually indicate the number of kilometers to determine the wear of the pads in the pads. They also always provide data on the minimum allowable thickness, which is indicated on the packaging.
According to the wear standards, the brake pad linings or the pads themselves need to be changed approximately every 15 thousand km. run. However, this indicator is conditional. A lot depends on how you drive. Yes, it significantly reduces the life of the pads. permanent use regime emergency braking. Due to a malfunction of the brake system, pad adjustments can fail prematurely.
The wear time largely depends on the mass of the vehicle. On a machine weighing more than 1800 kg, the replacement of the pads will need to be done earlier compared to a small car.
→ The service life of brake linings largely depends on the material from which they are made. Poor composition can lead to early wear of parts.
Replacement of brake pads
When the brake lining is worn, you can change the pads, or you can replace the linings themselves. As a rule, the replacement of brake linings is possible in drum brake mechanisms. As for disk brake mechanisms, then in them the pads to the pads are glued in the factory and cannot be replaced separately from the pads.
To replace the brake pads, you can purchase a special repair kit, which includes drilled and bored parts. It does not require any special skills or special equipment to carry out this work. The driver only needs a hammer and a chisel. With this set, you can install new brake linings in any conditions. At the same time, boring the pads for a certain size of the drum or drilling them is no longer needed. This saves time and money.
Every zealous owner of his car regularly inspects it before leaving, checking the level of oil, brake and coolant. But many car owners do not even think about periodically checking such a “little thing” as brake pads (slats), but in vain. In question accident-free driving there can be no trifles, because safety, and in some cases the life of people, directly depends on their condition.
It is clear that it makes no sense to dismantle the wheel every time to check the condition of the slats, there are certain signs that tell the driver about the approaching timing of their replacement. In this article, we will look at how to determine brake pad wear. And also what type of straps are there, which of them often have to be changed: front or rear. How many thousands of kilometers they can go and what in general you need to pay attention to.
The main working material responsible for the process of stopping the car is the friction layer attached to the metal part of the block. The perfect combination materials used in their production have not yet been achieved. Four types of brake bars are currently produced:
- Pads with a semi-metallic friction layer applied to them, in which up to 65% of copper, steel wire or iron powder components are found, mixed with graphite for better friction. Their plus is high heat transfer, and the minuses are quick wear and noise.
- Planks with glued to them material from organic components: high-temperature resin, rubber, glass, kevlar and carbon. To their positive qualities less noisy operation and softness can be attributed, and the negative ones are a shorter service life and enough the dust they emit.
- Pads with a low content of metal elements, not more than 30%, with the addition of organic (described above) substances. Which contributes to good heat transfer, but affects their noise.
- Ceramic slats counted on this moment the best option. Their friction layer is made of ceramic fibers with the addition of a filler that includes a small amount of copper. Lightweight, these pads last longer and produce less noise.
Factors Affecting Pad Wear
Let's take a look at the factors that affect how often brake bars will be replaced. There are few of them, but they directly affect such indicators as: how long this will happen, and how many kilometers the car will drive before the corresponding indicator on the instrument panel works. Here are some of them:
- Travel mode. When the car is moving in the city, it is often necessary to stop at short intervals, which contributes to rapid wear slats.
- Driving style. A non-aggressive driving style puts less stress on the brakes and increases the amount of time you need to change pads.
- The nature of the loading of the machine. With constant loading of the trunk, the load on the front brake bars decreases, respectively, and they will need to be changed less often.
Replacement timing and signs
Based on the model of the brake mechanism and the friction material of the slats, manufacturers indicate how many thousands of kilometers the pads can go. Manufacturers also recommend when to change the bars, focusing on the remaining minimum allowable friction layer.
All this is described in the instructions for the car, but there are average standards, the value of which ranges from 20 to 30 thousand km, for the front bars in disc brakes. And for the pads rear brakes drum, as well as disk type, this mileage interval in km must be multiplied by two.
Also of great importance, on the wear rate, is the mass of the machine. The above figures are relevant for small passenger cars weighing up to 1300 kg. If we consider big sedans weighing about 1600 kg, then the wear of the slats will occur one and a half times faster. For cars with a curb weight of 1800 kg or more, the replacement of the pads will need to be done after they cover a distance two times less than a small car can drive.
If the car was bought second-hand, there is often no way to find out when the pads were last changed, and what is their mileage. To understand that the time has come to replace them, some signs will help:
- The brake pad wear warning light on the instrument panel came on. Some brake slats have an electronic or mechanical indicator that gives a signal when the friction material wears out to a minimum limit and it is time to change them.
- There was a sound when the car stopped. This sound occurs when the friction material wears to a certain percentage when it wears down to metal.
- When stopping abruptly, a sound is heard and a beating is felt in the area of \u200b\u200bthe wheels. The reason for this is uneven pad wear or cracks and chips that may occur on the disc or friction layer. In this case, even the indicator, if present, may not work. Uneven wear of the friction layer is dangerous because after a certain number of kilometers it will be necessary to change not only the bars, but also the disk or wheel drum.
(Caution! Loud sound.)
- The braking distance and the time taken to stop the car have increased. This happens when uneven or complete wear of the slats occurs, in which case it is urgent to change them.
- Skidding due to uneven brake response, when one of the wheels seizes faster, and the second, on which the pads are worn out, is slower.
The most accurate way to know that it's time to change the brake bars is to regularly visually inspect them after the car's mileage has exceeded the generally accepted 30,000 km. In this case, a ruler or caliper will help to correctly determine the state of the friction layer. At the same time, its permissible residue should not be less than 1.5 or 2 mm, depending on the brand of car.
All of the above wear factors apply to rear brakes, regardless of their type. The only difference is that in the rear disc brakes, the methods of checking are similar to the front ones. The only difference that is relevant for the pads of drum mechanisms is that their wear can also be determined by the operation of the hand brake. If, when the handbrake is pressed on a slope, the slats do not keep the car from rolling, then it's time to replace them.
Also at visual inspection state of the brakes of the drum mechanism, in some models of machines a window is provided in the drum. Looking into it, you can determine the degree of wear of the friction layer of the pads.
Do not allow complete wear on the friction layer pads, set for yourself, depending on the driving style and other factors, the optimal mileage for your car, after which it will be time to take care of checking their condition.
The quality of braking directly depends on the reliability and serviceability of the brake system as a whole, and the condition of the discs and pads in particular. You cannot drive a vehicle with faulty brakes- this is rule number 1, which every driver remembers. In this regard, it is necessary to know how to determine the wear of the brake pads.
The problem is that they are subjected to a very high load. Therefore, over time, there is a natural need to replace them.
Now there are certain rules for monitoring the technical condition of the vehicle. According to them, the pads must be changed approximately after every 10 thousand kilometers. In addition, from time to time, you should simply carry out a diagnostic inspection, which will allow you to identify malfunctions.
Reasons for wear
As already mentioned, the pads and discs are under enormous stress, since they actually extinguish all the kinetic energy of a moving car.
Not only the distance traveled determines the degree of wear. Driving style has a huge impact.
If you prefer a quiet ride, devoid of sharp starts and braking, then the pads can remain in order even after 20 thousand kilometers. But if you often drive on dense city roads, and like to brake hard before every traffic light, then your pads may become unusable after 5 thousand kilometers traveled.
Characteristic features
The following symptoms indicate a malfunction:
Impacts during sudden braking;
Long braking distance;
Inadequate and strange behavior of the braking system;
The appearance of dust and metal chips on the pads and other elements.
Condition Diagnostics
Those. The main way to determine faults is the personal feelings of the driver. He, as a rule, knows very well how the car should behave on the road, so any deviations immediately make themselves felt.
The bottom line is that the pads wear out unevenly over time, which is why each wheel slows down with varying degrees efficiency. On the block that was subjected to a higher load, more cracks and chips form. As a result, it will make more noise and will start to knock harder when braking.
A striking example of the fact that brake pads need to be replaced is the decrease in the efficiency of the system as a whole. If you have to depress the pedal harder than usual when braking, then there is significant wear. In some cases, it happens that brake system works too sharply, this also indicates a poor condition of the pads.
After you have wound several thousand kilometers, you should regularly carry out visual inspection. In particular, it is necessary to look under the wheel cap. It is necessary to pay attention to the color of the plaque - if it is dark, then this indicates that the main lining is still preserved at the block. As soon as it is erased, metallic inclusions appear. The more of them, the more damaged the block.
Although it should be added that this diagnostic method is not suitable for ventilated brakes and alloy wheels.
During driving, the front brake pads are most stressed, as a result of which they have a much shorter life than the rear ones. In this regard, individual manufacturing companies even install special sensors that monitor the condition of the pads. If there is no such device, you must independently inspect and diagnose the condition.
The rear brake pads last about three times longer than the front ones, so there are much fewer problems with them.
However, you should not forget about them anyway. As soon as they become unusable, it is immediately necessary to carry out repairs.
If carried out regularly this procedure in accordance with all requirements, then the car will fully meet all established safety requirements. Thanks to this, you don't have to worry about something going wrong while driving. Even if you don't have time to do the repair yourself, you still need to know how to determine brake pad and disc wear. If necessary, you can simply drive the car to the nearest service center where the replacement will take place. Don't wait until the need technical inspection gets very sharp.
Video
Signs of worn brake pads in the following video:
The result of which should give an answer to the age-old question: is it worth paying for the original pads or can you put a cheap analogue, saving money and, maybe, health. Our experimental car ran 1,000 kilometers, and we decided to take intermediate measurements. I did not expect anything interesting from the numbers on the brake stand. As it turned out, in vain - they turned out to be impressive. But first, in a few words and three interjections, let us recall the essence of the experiment.
The idea of our experiment is as simple as the design of the Patriot. Remember the ad from the 90s, where half an egg is smeared with expensive toothpaste and then dipped in water, and the unprotected half of the shell becomes soft? For clarity, we did about the same thing: we put obviously “good” and “bad” pads on the car at the same time.
On right side car, we put pads from boxes with the inscription EGT. The Lithuanian company European General Technologies works with tens of thousands of manufacturers, packaging their products in boxes with their own logo. Cheaper than EGT, a set of pads could not be found. On the pads themselves there is also an inscription from three letters(Yes, yes, this is EGT), the packaging looks pretty decent, but it costs three times cheaper than those pads that we bought as original ones from catalogs by VIN code.
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Articles / Practice
Whether to save on braking: comparing expensive and cheap brake pads
What is the point? Brake pads have many characteristics by which they are checked by serious guys in white coats in laboratories on various stands and other high-tech devices. It turns out in general ...
20088 4 19 11.11.2016
On the rear pads (article 5K0 698 451 A) Bosch is written, and on the front ones (article 5K0 698 151) it is simply VAG. Kit for our Skoda Yeti cost 10,000 rubles, and we put it on the left. Before installing them on the car, the pads were measured with a caliper. The front pads of both sets turned out to be the same, there was no variation in the thickness of each pad either - exactly 20 mm everywhere. The Bosch rear pads were 18mm thick, while the EGTs were a bit narrower at 17.5mm. And just like with the front ones, there is no variation in the thickness of the pads - over the entire area, both analogues and originals are absolutely the same thickness.
Immediately after the replacement, we stopped by brake stand. At first, the operation seemed pointless to us: we did not even wait for the required 200 kilometers of run required to grind the pads. But the stand showed interesting figures: the braking force on the right on both axles was 13% less than the left. The value is insignificant, but an equal value of 13% both in front and behind has already made me think a little. But here are a few weeks - and the first thousand kilometers are left behind, the pads have worked in place, so let's check how they feel.
Pedal to the floor
I arrived at the car service a little earlier than Ilya in Skoda, our volunteer tester, who agreed to risk his brake discs and safety in the name of the brake truth that we are going to convey to readers. I called Ilya and asked when to expect him.
I'm driving from the Gostilitsky Highway, already in front of Kronstadt, I'll be back in half an hour. By the way, your pads stink.Ilya test owner
Drive from there to Savushkina Street (we conduct our inhuman experiments here, at the Discount Auto Service ROLF service station) for 60 kilometers. That is, both the pads and the motor will have to work hard to get there in half an hour. Ilya arrived in 20 minutes and immediately shared his impressions of the behavior of the pads for this thousand kilometers.
Firstly, there really is a smell on the right, and it is felt even in the cabin. But the saddest thing is that when braking, the car still drags to the left. With careful driving, this is not very noticeable, but for the sake of interest, our driver braked “to the floor” from a speed of 150 km / h. Here the Yeti has to be kept on course by the steering wheel - the difference between expensive and cheap pads becomes very noticeable. But we are for objectivity, so we will stand on the brake stand.
Of course, we hoped that the difference of 13% that we had initially would become less after the break-in of the pads. But the MAHA booth shattered our expectations, and to smithereens. We look at the final table with the results.
On the front axle, the difference in maximum braking force was 33%, and the specific one differs by 43%. And this is after running in the pads. The result is at least unexpected - it is already dangerous to drive with such a difference. And you won’t be able to pass the inspection, unless, of course, you buy diagnostic card from insurers who don't care about braking forces. There is no data on the table, but the ones on the left - the original ones - became more effective. Now let's take the pads off and see how they feel after a thousand miles.
Dropped millimeters
We start from the right front wheel(EGT pads). We will not look at dust and dirt - these are natural things. It would be worth paying attention to dust only under one condition: if the wheel disk would be too dirty, which would indicate excessive softness of the lining material. But we don’t have anything like that, the disks are dirty in moderation, according to the weather, and the right and left are the same. We remove the pads and inspect them.
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There are peculiar wear marks here - a pronounced rim, clearly visible in the photograph. We take a caliper and measure both pads in several places. The thickness of one pad over the entire surface was the same and amounted to 19.2 mm. The second pad also has uniform wear, but a little less - 19.5 mm. The difference is insignificant, and the wear during this time is small - the thickness of the new ones was, as we remember, 20 mm.
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We put the pads back and remove the original from the left front wheel. At first it seemed to us that a piece of lining just fell off the original front pad, but in fact it is not: it's just caked dust and dirt. There are no signs of wear on the eye, no defects either. And no matter how hard I tried to find something interesting with the help of a measuring tool, nothing came of it - both pads at all points showed exactly 20 mm, that is, exactly as much as it was three weeks ago. Such "non-wear" pads may be not bad, but how will this affect the resource of the brake disc?
Now let's remove the rear pads. And let's start with the original. Their wear is also absolutely uniform, but different from the external and inner sides. The thickness of one pad is 17.0 mm, the other is 17.5 (before operation - 18 mm). And on one of the pads, for some unknown reason, the metal lining came off.
