The most important organ in any car is the brake system. She must be in perfect condition Because our life depends on it. One of the main indicators of the effectiveness of this unit is the pedal, which must always be distinguished by the usual state of pressing for the foot. This rule must not be neglected, and at the slightest change, adjustment or repair must be carried out immediately. Below we will look at what needs to be done when the brake pedal becomes hard, does not press at all, or seizes at the very end of the stroke. We will also pay attention to self diagnosis and study all the causes of failure this mechanism.

Causes of brake pedal failure

Changes in the degree of effort to press the pedal occur due to a number of design violations, which can be both universal for all types of cars, and flaws in only certain models or series. We will consider a list of the main problems that can be called typical for modern and Soviet cars. As a rule, the failure of the brake pedal is a consequence of a malfunction of the VU ( vacuum booster) or GTZ (brake master cylinder). A detailed analysis of the performance and changes in the brake system will reveal the true source of:

blockage air filter VU. This element is not cleared. If a significant amount of foreign substances gets inside, which affects the performance, it is necessary to replace the amplifier with a new analogue.

Mechanical damage to the VU valve body. With minor defects, the mechanism begins to seize, which affects the force of pressing the pedal. Such a breakdown, unfortunately, cannot be repaired, but requires the replacement of the amplifier.

Diaphragm damage. A sign of the presence of this defect may be extraneous sounds when the braking system is activated. The failure is corrected by replacing the amplifier.

WU tip defective. This cause can also cause the brake pedal to grab at the end of the stroke. To fix the problem, unlike previous breakdowns, the replacement of the main element is not required. It is enough to install only a new tip.

The check valve does not work or sticks - it is eliminated by replacing this mechanism. The depressurization of this segment leads to the fact that fuel enters the cavity of the amplifier. In the future, this disables the entire node. As a result, you need to change the VU complete with a check valve.

Damage or loosening of the fastening of the hose connecting the VU with intake manifold. In the first case, the rubber tube must be replaced, and in the second case, the fastening clamps will have to be tightened or replaced if damaged. This reason is the most common and requires regular monitoring and inspection of fastening reliability. The condition of the hose must be checked regularly. It is made of a special polymer that becomes rigid when cooled, after turning on the engine and warming up, the material becomes flexible. Because of this, its throughput is reduced. As a result of this problem, there are malfunctions in the operation of the brake pedal. In order not to encounter this malfunction, you need to purchase high-quality parts, with specific thermal parameters.

Swelling of sealing rings in cylinders. If the brake pedal is not pressed, you should immediately check the condition of the elastic seals. Most often this happens due to the ingress of gasoline and oils into the components or the use of low-quality brake fluid. Depending on the degree of damage, the seals and low-quality brake fluid are replaced with an analogue recommended by the manufacturer.

Video - Why the brake pedal does not work

Diagnostics of the brake pedal

The correct state of pressing for the foot can be considered from different aspects. However, there can only be one answer. In an efficient and fully functional system, the pressing force always remains the same, there are no exceptions to this rule. It should be understood that uncharacteristic sounds are also a sign of failure. They arise in the process of mechanical action on the lever, while the pressing force can be unchanged. In such cases, you need to contact specialists or perform self repair.

Methods for diagnosing faults without special equipment

Start the power unit, this will create a vacuum in the brake system. Then step on the pedal. If it is still stiff, the booster or hose is faulty.

Stop the engine and without pressing the brake, wait 4-6 minutes. After the time has passed, press the pedal. If the lever has not lost its rigidity, most likely the VU valve is faulty.

With the engine off, depress the pedal several times. These actions will remove the vacuum in the brake system. Hold the pedal in the extreme position and start the engine. If the pedal goes down a little, then there is no problem with the WU. The latter method allows you to most effectively check the performance of the amplifier.
Diagnosing depressurization is very simple. A sign of this problem is the unstable operation of the engine, as they say, it “troit”. The reason for this is air getting into the intake manifold. In the process of depressurization, it sharply depletes air-fuel mixture. If the pedal does not press through with the car running, first of all, check the reliability of the connections. A sign of this breakdown is also a characteristic hiss from the vacuum booster on a running engine.

The above information will help in solving the problem with the "hardening" of the brake pedal. If any changes are found, do not delay the repair and fix the breakdown as soon as possible. You must always remember that efficiency brake system the safety of all road users depends.

Without brakes, as you know, neither in life nor in a car can you go far, because, in addition to acceleration, you also need to stop in time, prevent a collision with an obstacle, etc.

Let's consider how the VAZ 2110 brake system works, what malfunctions are the most common, and what improvements are possible in order to improve the brakes.

Scheme of the hydraulic drive of the brakes

Device

Installed on the machine and, in general, operate reliably hydraulic brakes. They are two-circuit, have a diagonal distribution. That is, if one part suddenly failed, then braking by another circuit is possible. For the sake of safety, the VAZ 2110 brakes work diagonally, one circuit is the right front and left rear wheels, the other also diagonally.

Such a device allows you to brake qualitatively (without skidding and other troubles) even in the event of a malfunction, if the brakes in one of the circuits have disappeared.

Consider the device of the braking system. The hydraulic drive includes a vacuum booster, as well as a dual-circuit regulator that creates pressure in the rear brakes.

The brake caliper device is described in this article:

In addition, the hydraulic drive is equipped with pipelines divided into two circuits, hoses and brake mechanisms that provide braking of the front and rear mechanisms.

Activates the hydraulic pedal located in the passenger compartment (middle). Here are the main components of the hydraulic drive:

1. vacuum booster. It is designed in such a way that it creates pressure on the piston of the master cylinder, and thus causes braking;

   Vacuum brake booster

2. Pressure regulator drive. It is through it that the working brake fluid enters the rear brake mechanisms;

   Brake pressure regulator drive

3. The pressure regulator itself. Already by the name it is clear that this device is responsible for the force of pressure, its decrease or increase. He does this depending on how loaded rear axle cars;

   pressure regulator

4. Master cylinder with pistons, equipped with a reservoir. The filler neck of the tank is equipped with an emergency TJ level sensor;

   Master brake cylinder

5. Brake mechanism for front wheel. Its main parts are the disc, pads and wheel cylinders. The mechanism also has a signaling device to prevent complete wear and malfunction of the linings;

   Front wheel brake

6. Brake mechanism for the rear wheel. Unlike the front, disc brakes, the rear ones are drum brakes. This is the factory set. However, many car owners believe that their device does not provide high-quality braking, and change them to disc ones.

Brakes require attention. Without waiting for the control light to light up, signaling a critical level of TJ or wear of the linings, and even more so, without bringing the brakes to disappear altogether, it is necessary to carry out preventive checks.

Particular attention is paid to all connections and hoses, since the “escaping” brake fluid will not make it possible to brake, and from here it is not far from the tragedy.

Alarms

The following symptoms are quite unsafe, please note:

1. If the brakes are completely gone, then definitely - you can’t go further, even to the service station! If self-repair on the spot is beyond your strength, or simply impossible, you need to call a tow truck;
2. When braking strong vibration, especially felt in the steering column. You press the pedal, and it's just hard to keep the steering wheel in your hands. There can be several reasons for vibration:
   Many argue that vibration can occur due to the fact that there are non-ventilated discs. Their device is such that they really do not like it when braking occurs in the rain, or even right in a puddle. No repair will help here - you need to replace the disks with ventilated ones;
   Vibration is also possible if there is a malfunction in the rear drums. If during inspection you find dark spots on the working surface, then this indicates uneven wear. In this case, the vibration is usually very strong. Such drums need urgent repair, and possibly a replacement for disc brakes;
   Check the front brake discs for deformation. At the same time, vibration is also observed.
3. The brake pedal is too hard. There may also be several reasons for this:
   A clogged air filter for the vacuum booster can cause the pedal to become tight;
   Check the vacuum booster itself. His possible faults- destruction of the diaphragm, tip, jamming of the check valve, damage to the hose connecting the intake manifold to the amplifier. In all these cases, hard pedal syndrome may be observed, and repair of any of the indicated malfunctions is needed;
   Also the pedal can get tighter as the pads wear, check those too.
4. Hissing when pressing the brake. If it hisses exactly at the moment you press the pedal, you need to urgently check the vacuum booster, and then decide what it needs - repair or replacement. But if it hisses when you release the brake, then this phenomenon is from the category of ordinary ones. Unless, of course, hissing is not too obvious.

Help with self-replacement rear brake pads given material:

Refinement

Many, believing that the brakes are bad, and repairs do not help them, decide on significant alterations and tuning. For example, tuning the VAZ 2110 brake system may include replacing the rear drum mechanisms with disc ones.

Here it is especially important to know that braking rear wheels should be softer and come on a little later than the front ones to prevent skidding.

Another possible tuning idea is to replace the vacuum booster as well. Instead of regular ones, they are installed from Lada Priora. This usually helps, first of all, in that there is no vibration felt, and the pedal works with optimal effort.

And do not forget - after each intervention in the operation of the brakes, they need to be pumped.

You can read more about replacing the vacuum brake booster in this material:

The braking system is the basis for the safe behavior of the car on any road. With her abnormal behavior, at least the main one, at least the parking one ( hand brake), it is recommended to correct the problem immediately. This is directly stated in the traffic rules, and this section of the rules must be taken into account. Malfunctions can manifest themselves in different ways. For example, the brake pedal has become hard - there may be various reasons for this. But until you understand what's wrong and fix the problem, you can't go anywhere.

Repair of the brake system is not a very expensive or very complicated car repair, if there is a lift or overpass. But the problems that may arise in real life traffic situation can have the most tragic consequences. Most inexperienced drivers who are accustomed to stable brake performance simply get lost when the car does not brake under normal effort, or the pedal suddenly drops. Only a special training on the circuit will allow you to properly brake the engine. And the last "line of defense" is a hand brake, so it must be in good working order.

Principal device of the brake system

• The brake pedal and the levers going from it to the amplifier.
• Vacuum booster (VU) - uses rarefied air from the engine to facilitate pedal operation.
• The main brake cylinder - evenly distributes the force received from the VU to each wheel. Brake fluid is used to transmit pressure.
• Metal tubes and rubber hoses - through them the fluid is pumped from the main brake cylinder to the working ones.
• Working brake cylinders and brake pads mounted on all four wheels, they provide inhibitory action per brake disc or drum.

If the pedal is not pushed

The force on the pedal is facilitated by a vacuum booster.

Too tight brake pedal - check the vacuum booster.

This means that if the pedal has become hard, or is pressed too tightly, the reason is related to it. It can be a corny disconnected or cracked rubber tube coming from the engine exhaust manifold. Or a breakdown of the VU itself, most often associated with its depressurization.

In rare cases, breakage or separation of the levers may occur - this will be associated with characteristic sounds when you press the pedal. Sometimes a foreign object or a bent part of the rug gets under the pedal.

Dips when pressing the pedal

High-quality and clean brake fluid is the key to the normal operation of the brakes. Due to its high density, braking force quickly transferred to the wheels. Over time, it deteriorates its properties, air bubbles form in it, moisture accumulates.

If the brake pedal is either soft or hard, check the brake fluid level.

If a slight depressurization occurs in any area, the liquid flows out, and air will get in its place. As a result, the brake pedal is either soft or hard. A few soft strokes cause pressure to build up in an insufficiently dense liquid. Then it is already working, and there is an effort.

First of all, you need to check the presence of liquid in expansion tank brake system, it is located on the master brake cylinder. If there is no liquid in it, you can’t go, a simple replenishment will not solve the problem. If you are planning an independent repair, you will have to find a leak - it can be any of the cylinders or some kind of tube.

Brake operation with the engine off

The pressure force on the pedal is connected to the vacuum booster. And the VU itself can only work with the engine on. With a long stop, the pressure in the vacuum chamber becomes atmospheric - the amplifier does not work. When you press the pedal, the force is transmitted directly from the levers to the master brake cylinder. The resistance on the pedal increases by 3-5 times.

A firm brake pedal after parking is normal.

If you start the engine while holding the pedal, it should fall slightly. You can safely go.

Control of technical condition a car is a conscious need for any driver who wants to ensure the safety of himself and others.

Hissing when pressing the brake pedal is one of the most common problems that occur in the operation of both domestic and foreign-made cars.

The thing is that most drivers react sensitively to various sounds that accompany the operation of car mechanisms. An exception is not the case when a hiss is heard when you press the brake pedal.

But it is far from always worth panicking - especially in cases where the hiss of the brake pedal when it is pressed does not affect the efficiency of the brake system in any way. In order to understand the nature of this sound, let's take a closer look at the operation of the vacuum brake booster.

Brakes are one of the main components of any car. And if, when you press the brake pedal, you hear hissing, creaking, the structure itself fails or, conversely, is too hard, you need to urgently correct the situation, do not tighten it and do not shelve it. possible repair. Or at least diagnose the causes of trouble. Knowledge and understanding of the problem accompanies its fastest resolution, and timely correction can save you from unforeseen situations on the road.

Hissing when pressing the brake pedal - the main causes

And so, why do the brakes still hiss when you press the pedal? In fact, there are not many reasons for this problem - only two:

1. Vacuum booster failed
2. Air brake system

We will talk about these problems and how to solve them in our today's article.

The level of hiss when you press the pedal - which is normal and which is not

There is a category of drivers who listen very carefully to every slightest creak or sound, and try to hear signs of breakdown in them. A car is a mechanical vehicle, in which there is a sufficient number of nodes and mechanisms that can create a small permissible noise level. You should not listen to this much and immediately go to service center, in which you, with great perseverance, will definitely find problems and offer to fix them. The brake pedal, when pressed, in most cases emits a slight hiss.

I must say that you need to check the brakes for the presence of various noises in the running state of the car. At the same time, windows and doors should be closed, and all devices that may emit additional noise should, if possible, be turned off. A slight noise level in the cabin may occur due to design feature brake system, which, as a rule, has two vacuum chambers. When you press the brake pedal, they different pressure, which causes a slight hiss. If it is minimal, and almost imperceptible, then there will be no problems during braking.

If at idle, when you press the pedal, you hear a loud, choking sound or a strong hiss, and it is pressed tightly, then you need to look for problems. First of all, the vacuum booster is checked. A tight pedal is not a sign of a breakdown of this part, especially in severe frost, but, coupled with a hiss, it indicates the need to check it.

The braking system is constantly used by the driver, so the elements of the system are under load. Whatever driving style the driver preaches, over time it is necessary to check the brakes for serviceability. This will ensure the safety of all road users.

The vacuum booster has a diaphragm, which over time, like any rubber material, begins to burst and crack. This does not allow full functional purpose- build up the required pressure. Intake vacuum can also get out of standing, but more often this is the first option.

Vacuum brake booster - how to diagnose a malfunction

Diagnosing a malfunction of the vacuum brake booster is not difficult, it becomes noticeable - brake pedal hard when pressed. But an indirect sign of a malfunction can also be changed turnovers idle move when the pedal is depressed . This is due to the depletion of the fuel mixture caused by the ingress of "excessive" air into the engine cylinders, which can even stall if the "choke" is too strong.

Most often this is due to damage to the brake booster diaphragm. Moreover, it is not at all necessary from old age - sometimes the sealing rings of the brake master cylinder let the brake fluid through, and it enters the booster housing.

Some car owners manage to sort out the brake booster on their own - on domestic cars They even sell kits. But, in general, this is a thankless task - the body of the “vacuum cleaner” is non-separable, and not everyone can neatly and tightly connect its parts.

In addition, the operation of the brake system is also affected by the adjustment of the protrusion of the "vacuum" rod from the housing - an incorrect setting can reduce the efficiency of the amplifier or cause incomplete "relaxation" of the workers brake cylinders. Among motorists, this method of checking the amplifier is common - start the engine, after depressing the brake. When starting the motor, the pedal should “go to the floor”.

The process of removing the vacuum brake booster

If the amplifier is faulty, then the brake pedal will still be "tight". In general, hissing associated with the operation of the vacuum brake booster is normal. But in the event that its volume increased for no apparent reason, get ready to replace the vacuum amplifier until it completely fails.

How to check the vacuum brake booster

The brake system of the car is constantly subjected to loads, and in the so-called aggressive driving style on city streets, these loads increase exorbitantly. In general, these kinds of impacts happen all the time, even if you prefer a loyal level of speed. Therefore, the brake system should be diagnosed with enviable regularity in order to provide the motorist with the maximum degree of safety. Malfunctions in the vacuum booster occur, as a rule, due to the loss of condition by the diaphragm located inside this assembly. It can burst or become covered with cracks, as well as the natural obsolescence of rubber and the loss of its qualities. What is the result? The diaphragm stops creating a vacuum. In some cases, the exhaust valve may also fail.

To check the performance of the vacuum amplifier, you need to resort to the following manipulations:

In general, each time you press the brake pedal, the engine speed will slightly decrease, however, if the difference becomes significant, it is worth visually diagnosing the hose connecting the amplifier with power unit. If it has any defects, then the collector will become leaky, respectively, you will not have to rely on normal mixture formation and the motor will work unstably. The solution is simple - we change the damaged hose.

Replacing the vacuum brake booster on a VAZ 2107 video

Air in the brakes how to fix the problem

Brake vacuum - most common cause Another thing is if the texture of the sound differs significantly by ear. That is, the hissing turns out to be quite loud and, as it were, choking.

At the same time, when pressing the brake pedal on a cold one, we feel excessive stiffness of its stroke. And also - the buoyancy of the engine speed (and sometimes it can stall). In such cases, close attention should be paid to the vacuum amplifier, as possible cause malfunctions.

Well, a tight pedal, of course, can also be from frost, for example, until the main one warms up. But here are the turns and a rather strong hiss - these are already direct indicators that you need to look under the hood! How to check it?

The brake system of the car is subjected to constant loads, and with the so-called sporty style of driving around the city, it is also overloaded. This happens regularly, even with a measured and unhurried rhythm - you can’t get away from this problem. Therefore, this assembly must be subjected to regular testing in order to provide the driver and passengers with maximum driving safety. So it is with brake vacuum. As a rule, malfunctions in its operation occur due to the failure of a special diaphragm located inside the device.

It bursts, cracks, ceases to fulfill the duties assigned to it - to pump up a vacuum. Sometimes the exhaust valve also fails. Available to each driver, the vacuum performance test on their own is carried out in the following way. We start the engine and let it idle for some time so that it reaches;

1. We turn off the engine;
2. We press the brake;
3. The first press will not differ in any way from the usual, standard one when the unit is running.
4. The pedal must be squeezed out as much as possible: at the same time, the diaphragm is extended in the amplifier and a vacuum is created;

Release the pedal, press it again. If there is something wrong with the system, then during the second approach, the vacuum will not be able to be created, and you will tactilely observe the uncharacteristic small stroke of the pedal itself. These changes indicate a breakdown in the brake booster.

How to bleed the brakes in 5 minutes - video

Good day, dear motorists! Let's continue our research typical faults vehicle braking system. A brake control element such as a brake pedal has several states of its position.

The first one, which should be regular, when the pedal is pressed without tangible changes, without dips, jerks, without much effort, etc. The next two states of the pedal position are unpleasant for the driver, and cause some anxiety.

We are talking about when you have a tight brake pedal or vice versa, too soft brakes. In this state of affairs, when the brake pedal stops working in the normal, familiar mode for us, the driver's concern is justified. So, there were any malfunctions, and it is required. Without delay.

Why do you have a hard brake pedal

There may be several reasons why the brake pedal suddenly becomes tight, and they may not necessarily be traditional and characteristic of all types and models of brakes. Nevertheless, we will consider the main, most characteristic causes, and methods for their elimination.

Most of the malfunctions that cause the brake pedal to become soft are “to blame”: either the vacuum booster or.

So, the increase in effort when you press the brake pedal is due to:

• the vacuum booster air filter is clogged. In this case, the air filter must be replaced;
• seizes the valve body in the vacuum booster. Exit - replacement of the vacuum amplifier;
• the diaphragm of the vacuum amplifier is destroyed. Change the vacuum booster;
• the tip of the vacuum amplifier is faulty - the tip needs to be replaced;
• stuck or not working check valve in a vacuum booster, a check valve needs to be replaced;
• the check valve of the vacuum booster is faulty (leaky), which allows fuel to enter the cavity of the vacuum booster. It is necessary to change the vacuum booster assembly with a check valve;
• the hose connecting the vacuum booster to the intake manifold is damaged, the fastening of the hose on the fitting is loosened. Change the hose, or tighten the fastening clamp. Learn more about the vacuum brake booster hose. His condition must be monitored systematically. Especially in the cold season. As long as the hose is not warmed up, it remains stiff enough and the brakes work normally. After a short engine operation, the hose heats up, becomes more elastic, and if you do not notice its delamination, for example, then its throughput decreases. There may be a problem with the brake pedal.
• O-rings swelled in the working (wheel) cylinders. This can happen due to getting into them fuels and lubricants or use of poor quality brake fluid. Repair of working brake cylinders, replacement of brake fluid recommended by the manufacturer.

A couple of ways to check the performance of a vacuum amplifier

Start the engine. A vacuum is created in the system. Now hit the brake. A hard brake pedal means a faulty booster or hose. After turning off the engine, wait about 5 minutes without pressing the brake.

Let's specify the problem. Step on the pedal. If the pedal is still stiff, then the vacuum booster valve is most likely defective.

One more test. With the engine off, press the brake pedal several times to release the vacuum in the brake system. Without releasing the brake pedal, start the engine. If the pedal goes down a little, then everything is in order with the amplifier.

Why do I have soft brakes

A soft brake pedal can indicate several problems. Rather, there are several reasons why the brake pedal suddenly became soft. This effect can also be called:.

Soft brakes have traditional causes:

• "" brake system. Naturally, air removal is required, i.e. . The cause of "airing" may be: depressurization of the system or low in the expansion tank;
• brake master cylinder failure
• malfunction of the working cylinder, for example, as a result of piston jamming or boiling of brake fluid. The brake cylinders need to be repaired, or a new one.

Good luck with the correct diagnosis and timely maintenance of the brake system of the car. After all, the brakes are our safety.