A car with faulty brakes is a dangerous weapon that can lead to mass destruction. Various technical problems can bring the vehicle to a state of uncontrollability. At the same time, only a collision that has occurred with any other car, the nearest structure or pillars can stop a car for which everything has failed. In such a situation, even falling into a ditch cannot be ruled out. Although, if the driver is experienced and he is attentive to each malfunction, he will immediately notice such a defect as a soft brake pedal and take all the necessary measures to avoid the most unpleasant fatal accident.
Perfect brake performance is essential when driving.
If you do not pay attention to such a significant lack of the braking system, the car owner may soon face bleak prospects - you can either become a victim of an accident yourself or be the culprit. And all just because of their own inattention or laziness. The timely diagnostics will allow you to remove all defects and replace the brake fluid, if necessary. A car enthusiast should feel the state of the brake pedal and react clearly to any deviation, since a working device will provide a quiet ride.
The brake pedal “went to the floor” - what to do?
If the brake pedal has become soft, that is, it began to fall significantly, - you should immediately check the entire brake system of the machine. Most likely, you will need diagnostics at a service center and its further repair.
The main thing is to contact the service center in time It is important to remember that all malfunctions of this kind are fraught with their consequences. Defective brakes can fail while driving, probably, this can happen on a busy avenue, only a collision with some other vehicle or structure can stop such a car even at an average speed. If the brake pedal is easily depressed, there may be several reasons:
- the brake cylinder is not able to retain fluid and the corresponding pressure, there may be significant wear on the cuffs and rubber gaskets;
- the wrong fluid has been added to the brake tank;
- there are malfunctions with pads or discs;
- defects are traced in the operation of the vacuum pump;
- the traction pedals may rust.
Problems with the braking system are clearly indicated by the presence of vibration, hissing and tapping on the pedal when it is pressed.
Solving the soft pedal problem
So, the most common problem is a bad, low-quality fluid, since it may not be suitable for a certain car model, hoses may gradually corrode. Rubber elements are not able to withstand such a liquid, they delaminate, increase in diameter, which leads to a loss of tightness. If the brake pedal has become soft, it is best to go through a diagnosis of the entire brake system, and defective elements.
The second reason is rust in the rods. There is only one way out - their complete replacement. It is possible to determine such a malfunction by holding the brake pedal, if it stays at the bottom and has to be “lifted” with improvised tools - there is definitely a problem in the rods.
The incorrect clearance that is located between the pedal and the cylinder is also determined by pressing the pedal. If pressing immediately occurs easily and smoothly, and at the end the applied force has to be doubled - most likely, the gap is incorrectly adjusted, the pressure present does not allow normal lowering and raising of the pedal. We'll have to adjust and bleed the brakes.
Air locks are also troublesome due to wear and tear on the hoses, causing breakdowns in the vacuum pump. The brake cylinders lose some of the pressure, the pads do not move apart, and therefore cannot be pressed against the disc. You should check the pads for the degree of availability.
Stiff brake pedal - what to do?
There may be several reasons why the brake pedal has become firm. It is worth noting that there are traditional malfunctions characteristic of most cars, and specific ones that can occur only in some models of the brake system.
A hard brake pedal may appear due to the following reasons:
- a blockage in the air filter. The malfunction disappears after replacing the filter;
- valve sticking. You can fix everything by replacing the amplifier;
- damage to the diaphragm. The firm brake pedal will disappear after replacing the booster;
- malfunction of the tip in the vacuum amplifier. The tip will need to be replaced;
- poor-quality functioning of the check valve, you will have to change the valve;
- leakage, which causes the flow of fuel;
- defects in the hose from the amplifier to the manifold. It is best to replace the hose. The condition of the hose should be checked regularly. It functions normally only in a cold state, any overheating makes it flexible and elastic, which may cause delamination in the future. They reduce throughput and cause brake problems.
- loosening the fastening of the rubber hose on the fitting. It is treated by tightening the fastening clamp.
A tight brake pedal can result from swollen o-rings in the cylinders. Such a defect occurs after fuels and lubricants begin to ooze onto the surface. In this case, you will have to repair the brake cylinders and.
Of equal concern is the malfunctioning of the vacuum booster. It should be checked regularly, for this, before starting the power unit, press the pedal, if the brake pedal is pressed tightly, there is a malfunction in the amplifier or hose.
In order to more specifically identify a place with a malfunction, press the pedal again 5 minutes after turning off the engine. If the brake pedal becomes tight a second time, the booster valve is faulty.
Conclusion
Many problems that a tight or soft brake pedal brings to the car owner can be solved by yourself. However, this will require a "baggage" of certain knowledge and skills, if there is uncertainty in one's own abilities, it is better to send the car for a full diagnosis to a service center.
If the brakes still fail, then the hope for engine braking Even despite the seeming foresight and serviceability of the car, the braking system can fail while driving, you can get out of this situation by braking with the engine. After a complete stop, you need to call a tow truck, as a faulty braking system can present new surprises.
Uninterrupted functioning of the vehicle's braking system (TC) is a guarantee of the safety of the driver and the people around him on the road. Any abnormal behavior of the brake (main or parking) is a reason for immediate repair. It is advisable to repair the vehicle in a car service, since only experienced "pros" can say with precision what really happened to it. After all, the reasons for the same malfunction in different cars are completely different.
An example is a situation where the brake pedal has become so firm that it is necessary to exert unnecessary force to move it and apply the braking action.
Such a malfunction is no less dangerous than the weakening of the pedal, as a result of which it fails. After all, both of them make the car practically uncontrollable in extreme conditions on the track. TS is a complex device, and its unsatisfactory operation can be caused by various reasons, the most common of them are given below:
- malfunctions of the vacuum booster;
- swelling of the rings;
- damage to the pedal.
Malfunctions of the "vacuum cleaner".
The vacuum brake booster (VUT), or simply "vacuum cleaner", creates the pressure in the vehicle vehicle necessary for their correct operation.
If the amplifier does not work well, the pedal simply does not push through. Since a vacuum booster is a rather complex part, consisting of many components, a failure of any of them can lead to this situation. And since the breakdown of the amplifier component, as a rule, requires its replacement, correct diagnostics will help save the car owner not only time, but also money.
If the filter element of the "vacuum cleaner" is clogged, it is enough to replace it only for the amplifier to function normally again. This also applies to a damaged diaphragm of the vacuum amplifier, and malfunctions with the tip or check valve. It is enough to replace one damaged component, and the vehicle will act like new again. It is important to accurately diagnose what exactly needs to be changed.
Sometimes no major replacements are required at all. For example, in a situation when the vehicle is depressurized. The sealing can be broken in two cases: either the hose between the "vacuum cleaner" and the intake manifold is damaged, or the clamps are loosened. And if in the first case it is still necessary to replace the hose, then in the second it is enough to tighten the clamps. This can be done in a car service, but the owner of the car is quite capable of dealing with such a problem on his own.
But it happens that the unsuitability of only one component completely renders the CWF unusable. This is most likely to happen in a situation where vehicle malfunctions are ignored for a long time. As a result, the heavily damaged valve moves to such a position that disables the "vacuum cleaner" entirely. An example is damage when a valve gets stuck in an amplifier and the latter has to be replaced completely. This is one of the most expensive types of vehicle repair.
Swelling of rings in cylinders.
The condition of the brakes largely depends on what kind of brake fluid is used during operation. If it is a product of a well-established company, the vehicle is rarely damaged or out of order. But if the fluid is of poor quality, one or more of the cylinders may not function well due to the swelling of the O-rings on them. The same thing happens when fuel and lubricant gets on the ring.
Earlier, especially in the era of the Soviet automotive industry, the car owner sooner or later had to sort out the working cylinders. Such a task was long and burdensome, even for professionals. But now hardly anyone will do it in the event of a vehicle malfunction. From the point of view of saving time, it is much easier to change them, and at the same time the brake fluid. However, you can avoid unnecessary financial costs if you use a high-quality, albeit expensive, fluid from the very beginning, since repair costs are always higher.
Pedal damage.
Sometimes the cause of damage to the vehicle is a malfunction of the brake pedal itself. Defects are different, but they are all associated exclusively with mechanical failures. Occasionally the levers on the brake pedals break or separate. An unmistakable sign of such damage is the characteristic sound that is heard when the pedal is pressed. Sometimes a pedal breakage is caused by a very simple reason - a foreign body that has got under it or a bent edge of the rug.
Self-diagnosis methods.
Depressurization of the vehicle can be determined immediately, if the engine is unstable - "troite". This is caused by air entering the intake manifold. The air-fuel mixture entering the cylinder is dramatically depleted during such a failure. A hissing sound is also a symptom of a vacuum booster malfunction. To concretize the breakdown, you should press the pedal a few minutes after the engine is turned off. If the stiffness of the pedal does not disappear, then, most likely, the check valve has broken.
If the vacuum booster is in good working order, the pedal “pumped” without starting the engine goes down when the engine starts to work.
Personal experience of car owners.
Alexey:
“I am a driver with little experience, so it was very difficult for me to independently determine the cause of the hardness of the pedal. I could not even figure out how to remove this or that part in order to diagnose specific problems. In the end, I drove my Audi A6 to a service station. The craftsmen working there determined the nature of the damage without even removing the units. Correct diagnostics helped me significantly save on repairs. "
Ivan:
“When my VAZ 2114 amplifier broke down, I made sure of its malfunction in a simple way. For this, the hose is removed, and the amplifier is muffled. The presence of a vacuum when starting the engine indicates that the "vacuum cleaner" is faulty. "
Novel:
“The vacuum booster and cylinders are very difficult to diagnose. The best vehicle diagnostics can be provided only by those car services where there are pressure gauges ”.
Video.
The most important organ in any car is the braking system. It should 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 differ in the state of pressing that is familiar to the foot. This rule cannot be neglected, and at the slightest change, adjustments or repairs must be carried out immediately. Below we will look at what to do when the brake pedal becomes firm, does not press at all or grasps at the very end of the stroke. We will also pay attention to the issues of self-diagnosis and study all the reasons for the failure of this mechanism.
Causes of brake pedal breakdowns
Changes in the degree of effort for pressing the pedal occur due to a number of design violations, which can be both universal for all types of cars, and flaws of 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, failure of the brake pedal is the result of a malfunction of the VU (vacuum booster) or GTZ (brake master cylinder). A detailed analysis of the performance and changes in the braking system will reveal the true source:
Clogged air filter WU. This item is not cleaned. 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 jam, which affects the force of pressing the pedal. Such a breakdown, unfortunately, cannot be repaired, but requires replacement of the amplifier.
Damage to the VU diaphragm. Extraneous sounds when the braking system is activated can serve as a sign of this defect. The breakdown is corrected by replacing the amplifier.
The VU tip is faulty. This cause can also cause the brake pedal to grasp at the end of travel. To eliminate 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 is stuck - it is eliminated by replacing this mechanism. Depressurization of this segment leads to the fact that fuel enters the amplifier cavity. In the future, this disables the entire unit. As a result, it is necessary to change the VU complete with a check valve.
Damage or loosening of the fastening of the hose connecting the VU to the 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 the fastening reliability. The condition of the hose must be checked regularly. It is made of a special polymer, which becomes rigid when cooled, and after the engine is turned on and warmed up, the material becomes flexible. Because of this, its throughput is reduced. This problem causes the brake pedal to malfunction. In order not to face this malfunction, you need to purchase high-quality parts with specific thermal parameters.
Swelling of the O-rings in the cylinders. If the brake pedal is not pressed, check the condition of the elastic seals immediately. 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 analog recommended by the manufacturer.
Video - Why the brake pedal does not work
Diagnostics of the brake pedal operation
The correct pressing state for the leg can be viewed from different aspects. However, there can be only one answer. In an efficient and fully functional system, the force of pressing always remains the same, there are no exceptions to this rule. At the same time, 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 a specialist or carry out an independent repair.
Troubleshooting methods 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 amplifier or hose is faulty.
Stop the engine and without applying the brake, wait 4-6 minutes. After the lapse of time, press the pedal. If the lever has not lost its rigidity, the VU valve is most likely faulty.
With the engine off, depress the pedal several times. These actions will remove the vacuum in the brake system. Squeeze the pedal to the end position and start the engine. If the pedal drops down a little, then there is no problem with the VU. The latter method allows you to check the performance of the amplifier as efficiently as possible.
Depressurization is very easy to diagnose. Unstable operation of the engine, as they say, "troit", is a sign of this malfunction. The reason for this is that air has entered the intake manifold. In the process of depressurization, the air-fuel mixture is sharply depleted. If the pedal does not push through when the car is running, first of all, you should check the reliability of the connections. A symptom of this breakdown is also the characteristic hiss from the vacuum booster when the engine is running.
The above information will help in solving the problem of "hardening" of the brake pedal. If you find any changes, do not postpone the repair and repair the damage as soon as possible. You must always remember that the safety of all road users depends on the effectiveness of the braking system.
Today we will understand the reason that the brake pedal has become hard or, on the contrary, very soft . Car manufacturers provide for such a behavior of the pedal, when pressing it does not cause failures, no vibrations, and it is not required to apply great efforts to the pedal to activate the braking system.
However, there are times when her pressing behavior is disturbing. Either or vice versa, it becomes overly tight. Both of these options are unacceptable and indicate a technical problem with the brake system.
Before repairing, it is necessary to understand what exactly needs to be repaired or replaced. Below we will analyze the most probable causes of malfunctions and possible options for their elimination.
Is the brake pedal firm?
A vacuum booster is responsible for creating the necessary pressure in the brake system, respectively, if it does not work properly, the driver simply cannot push the pedal:
- Clogged air filter vacuum amplifier. The solution is to change the filter element;
- The valve body is stuck in the "vacuum cleaner". We'll have to assemble;
- Damage to the amplifier diaphragm, there is also nothing you can do about it, you will have to change it;
- Handpiece malfunction. Again, a replacement;
- Incorrect operation of the check valve... Solved by replacing it;
- Violation of the tightness of the system. Depressurization can occur due to damage to the hose connecting the intake manifold and the "vacuum cleaner", loosening of the clamps. In the worst case, it is solved by replacing the hose, at the best - by tightening the clamps;
- Swelling of the O-rings in one or more working cylinders. This happens due to the use of low-quality brake fluid, or contact with the rings of fuels and lubricants. It is unlikely that anyone is burdening themselves with the bulkhead of the working cylinders, it is easier to simply replace them together with the brake fluid.
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Vacuum booster diagnostics
Unstable engine operation (tripping) is often a sign of depressurization. This happens due to air entering the intake manifold. It sharply depletes the air-fuel mixture entering the cylinders. If the pedal does not press when the car is running, first of all check the reliability of the connections.In addition, when the system is depressurized with the engine running, a characteristic hiss is heard from the vacuum amplifier.
To concretize the malfunction, turn off the motor and wait a few minutes without pressing the pedal. If after this time the pedal remains stiff, the most likely cause is a breakdown of the check valve.
Correct operation of the vacuum booster it is very easy to diagnose... To do this, without starting the car, you should "pump" the pedal, then, while continuing to hold it, start the engine. If the "vacuum cleaner" is serviceable, the pedal will go down.
The brake pedal falls through
There are several probable causes of increased pedal softness, and the most common is air intrusion into the brake system. Air can enter due to insufficient brake fluid level. To bleed the air, the brakes must be properly bled.
Pedal softness it can also be caused by malfunctions of the main or working brake cylinders, for example, due to boiling of the brake fluid or wedging of the pistons.
Regardless of whether the brake pedal has become hard or soft, this should immediately alarm any driver, to continue driving such a car means endangering not only yourself, but also those around you. And if it is not possible to fix the breakdown on the spot, it will be correct to contact the nearest car service.
The braking system is the basis for the safe behavior of the car on any road. In case of its abnormal behavior, even though the main one, even the parking brake (handbrake), it is recommended to immediately eliminate the malfunction. This is directly stated in the SDA, 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 firm - there may be various reasons for this. But until you understand what the matter is and do not fix the problem, you cannot go anywhere.
Repairing the brake system is not a very expensive or very difficult car repair, if there is a lift or overpass. But the problems that can arise in a real road situation can have the most tragic consequences. Most inexperienced drivers, accustomed to stable braking, simply get lost when the car does not brake with normal effort, or the pedal suddenly fails. Only special training at the circuit will allow you to properly brake with the engine. And the last "line of defense" is the handbrake, so it must be in good working order.
The basic structure of the braking system
- The brake pedal and 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, fluid is pumped from the master brake cylinder to the workers.
- The working brake cylinders and brake pads are installed on all four wheels, they exert a braking effect on each brake disc or drum.
If the pedal is not pressed
The pedal force is relieved by the vacuum booster.
Brake pedal too tight - check the vacuum booster.
This means that if the pedal becomes firm, or is pressed too tightly, the reason is related to it. It can be a trite disconnected or cracked rubber tube coming from the engine exhaust manifold. Or the breakdown of the VU itself, most often associated with its depressurization.
In rare cases, levers may break or disconnect - this will be associated with characteristic sounds when you press the pedal. Sometimes a foreign object or a folded part of the mat gets under the pedal.
Dips when pressing the pedal
High-quality and clean brake fluid is the key to normal brake operation. It is thanks to its high density that the braking force is quickly transferred to the wheels. Over time, it degrades its properties, air bubbles form in it, moisture accumulates.
If the brake pedal is soft or hard, check the brake fluid level.
If a slight depressurization occurs in any area, the liquid flows out, and air enters its place. As a result, the brake pedal is soft and hard. A few soft strokes leads to the accumulation of pressure in an insufficiently dense liquid. Then it works, and an effort appears.
First of all, you need to check the presence of fluid in the expansion tank of the brake system, it is located on the master brake cylinder. If there is no liquid in it, you cannot go, a simple replenishment will not solve the problem. If you plan to repair yourself, you have to find the place of the leak - it can be any of the cylinders or some kind of tube.
Brake operation when the engine is off
The pressure applied to the pedal is linked to the vacuum booster. And the VU itself can only work with the engine turned on. When parked for a long time, 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 brake master cylinder. Pedal resistance increases 3-5 times.
It is normal to have a firm brake pedal after parking.
If you start the engine while holding the pedal, it should fall slightly. You can safely go.
Monitoring the technical condition of the car is a conscious need for any driver who wants to ensure the safety of himself and those around him.
