How to change front brake pads. How to replace brake pads. How does the braking system of a car work?

On a note!

In modern cars, things are a little more complicated. Electronic system brake distribution The EDC checks (using speed sensors) whether more brake force should be applied to the front or rear axle. Depending on which ones have the best grip at the moment.

The ABS system, if one of the wheels slips, reduces the pressure of the brake fluid directed to its clip and activates impulse braking, preventing it from blocking.

Important!

Brake pads are the executive element of the brake system. If they are heavily used, braking will be ineffective.

How are brake pads arranged?

The basis of their design is a steel base (tablet), on which the manufacturer's marking, date of manufacture and other information are placed.

The second main element is the friction layer, that is, the working surface. Between the friction layer and the steel base there is a bonding layer and an insulating damping layer.

On a note!

As mentioned earlier, brake pads are also responsible for driving comfort. Therefore, in blocks designed for premium cars, additional damping elements are used.

This can be a damping film between the base of the block and the clamp, or a damping sheet (metal layer covered with rubber and silicone paper) used between the block and the clamp, or optionally between the friction material and the base of the block.

The third solution (not excluding the use of the previous ones) is a forklift attached to the base of the block, the task of which is to change the vibration frequency of the block during braking, which as a result calms its work.

The friction material of the pad consists of a mixture of metals (eg steel wool), fillers (eg iron oxide), release agents (eg coke powder) and organic materials (eg resins). Proportions are the secret of every manufacturer.

What is the durability of brake pads?

It depends on a number of factors such as:

The quality of the friction material from which the block is made.
How does the cooperation between brake disc and brake pad work.
The condition of the brake disc - for example, a warped disc will cause rapid damage to the block.
The way you drive. Sporty, aggressive driving, frequent mountain driving, frequent city driving - all this causes accelerated wear of the blocks.

You can assume that good, branded brake pads, when correct use, can withstand up to 70,000 km, of course. The cheapest can withstand from 20 to 30 thousand. km, of course.

On a note!

Symptoms of damaged brake pads are, of course, poor braking performance and all sorts of noise during movement and braking. This can be caused by wear sensors on the acoustic linings (metal inserts), which are designed to warn of insufficient thickness of the friction layer.

Premium cars use electronic brake pad thickness sensors. They warn you that the block is too small with the help of a backlight on the dashboard. The blocks are replaced when the friction lining thickness is less than 3 mm. Also, when the shell is cracked, chipped, or unevenly worn (for example, beveled on one side).

How to replace brake pads in a car?

Blocks are always replaced in pairs on one axle (front or rear) or on both axles of the vehicle. They are chosen for specific model, year of manufacture and version of the car engine.

On a note!

High-quality pads extend the life brake discs. The cheapest ones, if their shell is hard, can cut them effectively.

Repair begins with loosening the bolts securing the rims to the hubs.
The car must be immobilized and raised. In the workshop - on the lift. At home - raise the chassis with a jack (place it in the place intended for support - it is marked on it).
The wheel(s) must be unscrewed and removed.
The next step is to unscrew the brake calipers. Unscrewing the bolts can be inconvenient due to their formwork. To facilitate the disassembly of the screws, special tools and penetrating lubricants.

After disassembling the clamp, it must not be “hung” on the brake line so as not to damage the cable.

This is a good opportunity to check the condition of the flexible brake hoses.

The next step in the repair is to check the condition of the brake pistons. Seals most often break in them, and the metal pistons themselves can corrode. The reason is the untimely replacement of the brake fluid.
The next step is to insert the pistons and install the brake pads into the clamps and assemble them. In premium cars, sensors must be installed to measure the thickness of the blocks.
The pad guides should be lubricated with high temperature copper grease and the terminal slots should be cleaned. The terminals themselves must be cleaned of corrosion, for example with a wire brush.

They can also be thoroughly cleaned, degreased and painted. This good protection from rust.

The next steps are to install the clamp, screw in the wheel and lower the car.
After replacing all brake pads, check the brake fluid level as well as the system.

After assembling the blocks, it is worth remembering that the first few hundred kilometers should not be braked quickly, because the blocks must be correctly positioned.

On a note!

Any deviations from the standard, such as the car pulling during braking, poor braking performance or noise, are the result of improper assembly of the blocks. You must repeat this as soon as possible.

Replacing brake pads - do it yourself or in a workshop?

How much does it cost to replace brake pads? The average price in the workshop is 2000-3000 thousand rubles. In professional workshops, such an exchange lasts up to an hour. At the request of the client, mechanics can independently order and purchase brake pads for a specific car model.

Why choose a replacement workshop?

The cost of the service is low and the repair time is short.
Brake pads are a guarantee of safe driving, so improper assembly plays a role in the safety of you and others.
During replacement, the mechanic can check the condition of the remaining parts of the brake system and, if necessary, repair or replace them. This mainly applies to flexible brake hoses and pistons.
The use of specialized workshop tools and equipment (e.g. an elevator) facilitates and speeds up repairs.

What are the risks of changing brake pads yourself?

This is especially inconvenient without a lift.
You need to have a range of tools.
The hobbyist must devote a lot of time to replacing and may run into problems that can outgrow his skills.
Improper assembly of the blocks will cause the car to steer during braking, or it will be due to low braking performance, resulting in a decrease in safety.
In some vehicle models, changing blocks requires the vehicle to be connected to a diagnostic computer so that the brake piston can be retracted.

The brake system is one of those that is used more often than others, and therefore, even at the design stage, it is given the closest attention. Manufacturers do their best to make it last as long as possible. But still, there comes a time when the brake pads need to be replaced. The wear rate depends on many factors: the type of gearbox, operating conditions, manufacturer, driving style, etc. The main thing is to remember that in no case should you hesitate. Not only your own life depends on it, but also the lives of those around you.

When to change?

Before you ask yourself how to replace or rear, you should determine for sure that this moment has come. How to do it? Yes, very simple. As a rule, they are equipped with a special wear sensor that starts to emit a nasty metallic screech when braking, which is almost impossible not to hear. In any case, it is necessary to carry out a periodic visual inspection of the brake pads. If their thickness has become less than 3 mm, and there is no screeching, you can safely proceed with the replacement.

Which ones to choose?

Before replacing brake pads, you need to decide on their choice. It is advisable to buy original parts, choosing them from special catalogs depending on the brand of car, year of manufacture, body type, etc., or purchase goods from well-known manufacturers. Otherwise, you can easily run into a fake.

The safety of the driver and passengers depends on the condition of the pads. The car owner must know when to change the brake pads. Of course, the service life of these Supplies largely depend on the quality, driving style and conditions. But to maintain braking efficiency, they need to be closely monitored. Let's look at what affects the life of the pads, how to replace them yourself.

Resource brake pads

The wear rate of these elements largely depends on the material from which they are made, as well as on the quality of the friction linings, the condition of the brake system cylinders, and driving style. Experienced mechanics in car services, as well as car enthusiasts, know how long pads can be used. Well, as for the resource, it is approximately determined by the mileage of the car. How much to change the pads can also be found in the documentation for the car. Lining wear also depends on the type of brake. For example, for disk systems, the average resource can be from 50 to 80 thousand kilometers.

Interestingly, for the resource is about the same, although the load on the rear axle is lower. The service life also depends on the conditions in which the car is used, on the driving style, as well as on the experience of the driver. If you accelerate intensively and often brake, then such driving greatly reduces the resource. Often, guys and girls who have just got behind the wheel of their car forget about it and can drive with the handbrake on. This does not have the best effect on the resource of parts of the brake system. Long braking on long descents does not have a very good effect on the state of the pads. How often to change pads? You can replace according to the level of wear. But it is better to carry out the installation as recommended by the manufacturer of a particular car. IN this procedure should be made on a run of 60 thousand kilometers. In practice, it turns out that on this run the pads can be either already worn out or still in normal technical condition.

We diagnose the condition

In service stations, diagnostics are performed by measuring the thickness of the friction lining.

To do this, the car is installed on a flat floor. One of the sides of the car is raised with a jack, or the car is immediately placed on a lift. Then the wheel is dismantled, and with the help of a caliper, the thickness of the lining and disc is measured. If the thickness of the pads is less than 2 mm, then replacement is necessary. Also during the diagnostics, the condition of the disk or drum is checked. If the thickness is less than a certain level, then the part must also be replaced.

Diagnostics without service stations and measuring instruments

To understand when to change the brake pads, you can do without a trip to the service. You can understand that the time has come, and the lining has become unusable, using a visual inspection. By the highlighted marks, you can easily understand that the friction lining is already very worn out. Also, experts recommend monitoring the level of brake fluid in the expansion tank. If it has decreased significantly, or the block has worn out and requires urgent replacement. Do not delay with repairs - this is your safety. You can check when to change the brake pads and in a different way.

To do this, you need to accelerate the car to about 80 km / h, and then perform emergency braking. The beating on the pedals will tell you about the wear of the elements of the brake system. But here the disk is worn out. A signal that the consumables of the brake system need to be replaced soon may be a change in the braking process and the behavior of the pedal. For example, if the car slows down more sharply or slower than usual, then it is worth considering. Characteristic dust with chips may form on the surface of the discs. If, in the process of reducing the speed, the grinding of metal on metal is clearly audible, then it is recommended to pay attention to the thickness of the installed lining and the very presence of the friction layer.

Pad condition monitoring system

Many modern cars have electronic systems.

They take full care of the owner. Special sensors will tell the computer how much to change the brake pads, and he will display this information to the driver. On various models, they may simply indicate that wear is critical and replacement is needed right away.

The device and principle of operation of the sensor

The element is very simple - there is a soft metal core in the overlay. If the level of wear approaches critical, then it becomes the initiator of the circuit. The corresponding signal will be sent to the instrument panel. But even if the sensor is installed, one nuance must be taken into account. It doesn't work correctly every time. Sometimes there are crashes and false positives. This situation is due to the fact that the brakes are often in contact with moisture. The result is corrosion. And because of it, the sensors fail. It is important to know when to change the brake pads by visual inspection - this is much safer.

Before replacement

When installing the pads, it is necessary to diagnose the condition of all mechanisms and components in the system.

Be sure to check the condition of the brake disc. It is enough to measure its thickness with a caliper. It will also not be superfluous to make sure that there are no damages on the surface of the disk, and the element itself is not deformed.

Replacement process

To change the pads at the front, you will need a jack or any support with a lifting function. You also need a wheel wrench and a set of tools. Next - they hang out the front of the car, dismantle the wheel from the right side, take out the brake hose. Then press the piston with a balloon wrench. Do not forget that this will increase the level of the brake fluid. It is necessary to monitor the expansion tank.

How to change rear brake pads

Everything is not complicated here - the algorithm is almost the same for different models and brands of cars. The car is raised with a jack and the desired wheel is dismantled. Then the pins are unscrewed, the drum is dismantled from the hub. This is best done by tapping on the drum with a hammer.

Next, the spring is disengaged from the shoe, and the first step is to remove the upper spring. Only after that the bottom. Then remove the front block and the spacer bar along with it. Next, removing the clamping spring from the rear, lower it. After that, the block lever is removed from the hole for the tip. Then the cotter pin is pulled out of the hole, the washer and finger are removed. The next step is to install new pads. The mechanism is assembled in the reverse order. To mount the pressure spring and pads, use the lower spring. She clings to the hook. Then the spring is pulled with a screwdriver and its hook is inserted into the hole on the block. The pistons are moved to the center of the cylinder by bringing the front and rear linings together with mounting blades. Here's how to change the rear pads - it's really easy. Even beginners can handle it.

When moving. The main task of this system is a partial slowdown of the car, as well as its complete stop. The traffic rules state that it is completely forbidden to operate a car with a faulty brake system.

The elements of the braking system must be carefully monitored

Design and principle of operation of brake mechanisms

These mechanisms are installed on the wheel hubs and are an intermediate link between the hub and the wheel, due to which the possibility of slowing down is realized.

Often, disc mechanisms are installed on the front axle, and drum mechanisms, since they are also used as a parking brake, on the rear. Although there are many cars that have disc brakes on both axles.

The principle of operation of the drum mechanism is as follows: the drum with the wheel fixed on it rotates freely around the axis of the hub, the brake pads inside the drum are in a compressed state. The pads are compressed by two springs. The lower part of the pads is installed in the mounting grooves of the hub, and top part- into the grooves of the pistons of the working brake cylinder.

When exposed to the pedal, the fluid under the action of force presses on the pistons, they begin to exit the cylinder, pushing the pads and overcoming the force of the coupling springs. The pads are unclenched and come into contact with the drum. The friction that occurs between them slows down the rotation of the drum, and with it the wheels. The more force the liquid transmits, the more the pads will be pressed against the drum, and the braking will be more intense.

Removing the caliper from disc brakes when replacing pads

Disc mechanisms have a slightly different design and principle of operation. Brake pads are installed in a caliper, which has a U-shape. The caliper itself can move longitudinally on its mounting bolts. On one side, usually internal, a brake piston is installed in the caliper, and the caliper itself plays the role of a working cylinder. The piston rests against one of the pads.

The mechanism works like this: a disc placed between the pads, if braking is not performed, rotates freely. When force is transferred, the piston exits the cylinder and begins to press the pad against the disc. The force created by the fluid on the caliper piston not only presses one pad, it also forces the caliper itself to move along the axis, and the pad located on the other side of the disc also begins to press against it. This ensures the two-way impact of the pads on the disc.

When do you need to replace your brake pads? signs of wear

From the foregoing, it is clear that the main element of this mechanism are the pads. Their frequent interaction with the drum or disc leads to the abrasion of the friction linings, after which the replacement of the brake pads will be required. There are several signs that your brake pads need to be replaced:

Video: How to replace brake discs and pads

A screeching sound is heard when braking. The appearance of sound indicates the complete erasure of the friction linings and the metal part of the pad is already interacting with the drum / disc.
Braking is too slow or too fast. With severe wear of the friction linings, the gap between the shoe and the drum / disc increases. This gap affects the time required for full contact of the lining with the drum / disc, and also changes the stroke of the brake pedal, it is required to press the pedal more, and as a result, an increase in effort. Because of this, braking is slower. The absence of friction linings leads to the fact that during braking, the metal part of the pad and the disc / drum begin to interact with each other. The friction between them increases significantly - braking occurs faster than usual. In this case, the interaction of metal parts significantly damages the surface of the drum/disk;
. This happens due to uneven wear or damage to the friction lining. The appearance of a beating also indicates that the replacement of the brake pads is required.

If at least one of these signs appears, the brake pads are replaced.

Replacing the front brake pads

As already mentioned, disc mechanisms are installed on the front of the car, and since the design of such a mechanism is simpler, it is also easier to replace the front brake pads.

Replacing the front brake pads

To replace the front brake pads, the car must be installed on a flat area, put it on the parking brake and throw the wheel chocks under the wheels. Then the car is jacked up from the side where the front brake pads will be replaced, the wheel bolts are first loosened.

After jacking up, the wheel is completely removed from the hub. At this stage, you can visually assess the condition of the pads, if their strong wear is noticed, they change. To do this, unscrew one of the caliper mounting bolts. Next, the caliper is removed from the disk by turning it around the axis of the second mounting bolt. Then the worn pads are removed from the caliper.

Video: VW Passat front brake pad replacement video

Before you change the front brake pads, you will need to sink the piston into the brake cylinder, otherwise it will be impossible to install the caliper in place. You need to press it with effort, but carefully, since the caliper is made of aluminum and it is not difficult to damage it.

After the piston is pressed in, pads are installed in the caliper, it is put in place and fixed back with the mounting bolt. After that, the wheel is installed in place and the car is removed from the jack.

Replacing the rear brake pads, if they are disc, is done in the same way as in the front.

Replacing the rear brake pads

But if a drum mechanism is installed at the back, replacing the rear brake pads is more time-consuming, especially disc ones.

Replacing pads on rear drum brakes

Again, the wheel where the brake pads will be replaced is jacked up and removed from the car. To remove the drum, you will need to unlock the drum fastening nut and unscrew the nut itself. Then, carefully prying the drum from different sides, it is removed from the hub axis. When removing, it is important to follow the bearing that is installed in the drum. If there is a parking brake mechanism, then it is removed.

Before replacing the rear brake shoes, it will be necessary to drown the pistons in the working cylinder. After that, the pads are put in place. After that, they are fixed with clamps, coupling springs and a parking brake mechanism are installed on them. Then a drum with a bearing is installed in place and it is tightened with a nut, the nut itself is locked. After the wheel is installed. The rear brake pads of the drum mechanism have been replaced.

It is important to consider that the replacement of the pads is carried out at least in pairs, that is, if the pads on one front wheel are replaced, then they need to be changed on the second. And it is better to replace the pads at once on all wheels.

Welcome to our automotive portal! Nothing lasts forever in our world, and, alas, no matter how regrettable it may sound, it will be difficult to disagree with this. And if we talk about the details of the car, which are operated in a constant mode as extreme as possible, then this statement hits the bull's-eye like never before. These parts include brake pads, which, together with brake discs, work hard, ensuring the safety of all motorists. Let us especially pay your attention to the front brake pads, as they experience a significantly greater load during braking. It is they who take on the entire weight of the car, multiplied by its speed. Their main function is to quickly and most effectively stop this explosive mixture of various physical energies.

If the pad resource is close to the extreme point?

If you do not resort to the help of various equipment and do not carry out various kinds of measurements, then only with a visual inspection you will be able to understand when the brake pad resource is already at its extreme point or has already crossed even this line. How can this be done, you ask? We will answer that very simply:

1. Brake fluid level control. If the level of TK in the tank began to decrease significantly, then this is the first evidence that either the brake pads or discs, or both, have undergone wear.

2. If you make extreme braking at an average speed of about 80 km / h and feel the beat. This is a direct result of pad or brake disc wear.

3. How does the brake pedal work? Braking that goes beyond the usual: sharp or vice versa slow, should make you wary.

4. The appearance of brake dust on discs with obvious deposits of metal chips. And if a rattle is still heard during braking, then you should definitely pay attention to the thickness of the brake pad or, in general, the presence of the friction lining itself. Although if it is absent, then you will immediately understand this sound.

5. Brake pad sensor alarm, if available. This sensor works according to the simplest principle. A soft metal core is mounted in the friction lining.

If the pad wear is critical, then an electrical short occurs and signals are sent through the indicator on the control panel, indicating to the driver that it is time to change Although, if there is such a sensor, consider one significant "but": it does not always work correctly, sometimes there are misfires. And this situation is connected with the fact that the wire is constantly in contact with a humid environment and due to the appearance of corrosion, it may lose its suitability. Here, the interpreted statement “Rely on the sensor, but don’t make a mistake yourself” will be very useful here. Even if a brake pad wear sensor is installed on the car, a visual inspection once again for suitability will not be redundant, and it will not take long at all. After all, this is the source of our security. Spending a little time to ensure that the brakes are always in good condition, this is quite a trifling matter.

How often to change brake pads?

The service life of both the front brake pads and, in principle, the rear brake pads depends on a combination of several factors. Influence on a significant part of them is in the power of car owners.

1. A company that manufactures brake pads. Let's take into account the fact that the elements of the brake mechanism are our safety and, choosing them, in no case be guided only by the price policy. Yes, of course, brake pads of world brands are quite expensive, but this does not mean that you can ignore your health and life safety. The game is not worth the candle.

2. The quality of brake pads and their degree of wear depends directly on the brand that produces them. We recommend that you buy this product only in branded stores. You will be sure that each product is properly certified.

3. Driving style. This factor, as already clear, depends entirely on you. Brake pads wear out many times faster if the driver moves through the city at a speed exceeding the necessary one. The desire to prove or show something to someone is simply inappropriate in the city traffic mode. For this, there are specialized autobahns and places where you can burn rubber. A clear example is jerking from a traffic light, followed by gaining the maximum possible speed and sharp emergency braking. For lovers of this style of driving, the need to replace the front brake pads comes many times faster than the manufacturer expects.

When to change brake pads?

Of course, manufacturers cannot name the exact mileage or time when it will be necessary to replace the pads. But for each car brand, there are certain parameters for the state of the brake pads, upon reaching which they need to be replaced. You can observe these values in the instructions for using the brake pads and in the manual for operating the car of your make and model. It is recommended to systematically monitor that when the specified thickness of the brake pad is reached, you replace it.

Replace the brake pads and, it is necessary according to a scheme similar to shock absorbers, that is, on two wheels of the same axle. There are no great difficulties in this task. But if you do not know how to properly replace the brake pads of a car, then we will be happy to help you with this.

How to change front brake pads?

Replacing brake pads on any car is almost identical. Well, of course, there are certain nuances that are associated with the designs of brake mechanisms or their types. The caliper on disc brakes differs from the standard brake system in its design.

When replacing the front brake pads, and in principle the same as the rear ones, do not forget about the diagnostics of parts, mechanisms and assemblies of the entire brake system. Be sure to check your brake disc. Just armed with a caliper, check its thickness. After measuring the thickness of the disc, make sure that there is no damage on the surface of the disc: chips, cracks, as well as its deformation.

When buying brake pads, try to choose them from the same lot. Why? And here's the thing. The material of friction linings in different batches of brake pads may vary in its features. The pads that came in one batch are minimized in the difference in the physical and mechanical properties of the material from which they were made.

We present to your attention the standard toolkit for replacing the front brake pads:

Support with the possibility of lifting;

balloon wrench;

Standard locksmith tools: hammer, wrenches, screwdrivers, etc.

1. We hang the front of the car with a jack on a lifting support.

2. Remove the front wheel and unscrew the steering wheel.

3. We estimate the amount of work to be done and check the condition of the entire brake mechanism.

5. We press the brake piston with a balloon wrench or a mount, whichever is more convenient for you. Do not forget that at the same time the level of the brake fluid begins to rise. Let's take a look at the expansion tank.

6. We remove the caliper by unscrewing the bolt holding it with the mounting bracket.

7. We change the column. We assemble the brake mechanism in the reverse order.

That's it, it's not all that complicated. We have successfully replaced the front brake pads. You will immediately need to test them, but without undue zeal. And remember one important point. Increasing the load on the front brake pads, systematically monitor their condition. This is your guarantee of safety.