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What you need to know about the brake system of a car?

For road safety, every vehicle must not only be able to maneuver efficiently, but also stop within a short distance. And the second factor is more important. For this purpose, any vehicle has a braking system.

About the device and modifications of the steering we said a little earlier. Now let's consider the braking systems: their structure, malfunctions and operating principle.

What is a braking system?

The braking system of a vehicle is a set of parts and mechanisms, the main purpose of which is to slow down the rotation of the wheels as soon as possible. Modern systems are equipped with electronic devices and mechanisms that stabilize the vehicle under emergency braking conditions or on unstable roads.

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Such systems and mechanisms include, for example, ABS (about its structure Read here) and a differential (what it is and why is it needed in a car, it is told in another review).

A short digression into the history

As soon as the wheel was invented, the question immediately arose: how to slow down its rotation and make this process as smooth as possible. The first brakes looked very primitive - a wooden block attached to a system of levers. When in contact with the surface of the wheel, friction was created and the wheel stopped. The braking force depended on the physical data of the driver - the more the lever was pressed, the faster the vehicle stopped.

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Over the decades, the mechanism was being refined: the block was covered with leather, its shape and position near the wheel were changed. In the early 1900s, the first development of an effective car brake appeared, albeit very noisy. A more improved version of the mechanism was proposed by Louis Renault in the same decade.

With the development of motorsport, significant adjustments were made to the braking system, as the cars increased power and, at the same time, speed. Already in the 50s of the twentieth century, the development of really effective mechanisms appeared that ensure the rapid deceleration of the wheels of sports vehicles.

At that time, the automotive world already had several options for different systems: drum, disc, shoe, belt, hydraulic, and friction. There were even electronic devices. Of course, all these systems in modern design are very different from their first counterparts, and some are not used at all due to their impracticality and low reliability.

The most reliable system these days is the disk one. Modern sports cars are equipped with large discs that are paired with wide brake pads, and the calipers in them have from two to 12 pistons. Speaking of the caliper: it has several modifications and a different device, but this is a topic for another review.

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Budget cars are equipped with a combined braking system - discs are attached to the front hubs, and drums are attached to the rear wheels. Elite and sports cars have disc brakes on all wheels.

How the brake system works

The brakes are activated by pressing the pedal located between the clutch and gas pedals. The brakes are operated hydraulically.

When the driver presses the pedal, pressure builds up in the line filled with brake fluid. The fluid acts on the piston of the mechanism located near the brake pads of each wheel.

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The harder and harder the driver presses the pedal, the more clearly the brake is applied. The forces coming from the pedal are transmitted to the actuators and, depending on the type of system, on the wheels either the pads clamp the brake disc, or they move apart and abut against the drum rims.

To convert the driver's efforts into more pressure, there is a vacuum in the lines. This element increases the flow of fluid in the line. Modern systems are designed so that if the brake hoses are depressurized, the brake will still work (if at least one tube remains intact).

The brakes are described in detail in the following video:

How the brake system and vacuum booster work.

Brake system device

Machine brakes are composed of two categories of elements:

The brake drive is of the following types:

What you need to know about the brake system of a car?

The braking device includes:

Brake gears

The car decelerates with two types of brakes:

These two types of mechanisms are included in the device of the main brake system of the car. It works as usual - when the driver wants to stop the car. However, every car also has auxiliary systems. Each of them can work individually. Here are their differences.

Auxiliary (emergency) system

The entire brake line is divided into two circuits. Manufacturers often connect the wheels to a separate circuit along the diagonal of the car. The expansion tank, installed on the master brake cylinder, has a baffle inside at a certain level (corresponds to the critical minimum value).

What you need to know about the brake system of a car?

As long as the brakes are in order, the volume of the brake fluid is higher than the baffle, so the forces from the vacuum are applied simultaneously to the two hoses, and they work like one line. If the hose ruptures or the tube breaks, the TOR level will drop.

A damaged circuit cannot be pressurized until the leak is repaired. However, due to the partition in the tank, the liquid does not leak out completely, and the second circuit continues to work. Of course, in this mode the brakes will work twice as bad, but the car will not be completely devoid of them. This is enough to safely reach the service.

Parking system

This system is popularly called simply the handbrake. It is used as a recoil mechanism. The system device includes a rod (a lever located in the cabin near the gear lever) and a cable branched into two wheels.

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In the classic version, the handbrake activates the main brake pads on the rear wheels. However, there are modifications that have their own pads. This system does not depend at all on the state of the TJ in the line or system malfunction (malfunction of the vacuum or other element of the main brakes).

Diagnostics and malfunctions of the brake system

The most important brake failure is brake pad wear. It is very easy to diagnose it - most modifications have a signal layer that, when in contact with the disc, emits a characteristic squeak during braking. If budget pads are used, then their condition must be checked at the interval specified by the manufacturer.

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However, this regulation is relative. It all depends on the driving style of the motorist. If he likes to accelerate sharply on small sections of the road, then these parts will wear out faster, since the brakes will be applied more actively than usual.

Here is a small table of other faults and how they manifest themselves:

Malfunction:How does it manifest:Repairs:
Wear of the friction layer on the pads; Breakage of the main or working brake cylinders; Breakdown of the vacuum.The efficiency of the braking system has decreased markedly.Replace the pads (if the driving style is very active, then better models should be used); Check the health of the entire system and identify the broken element; If non-standard rims (for example, larger diameter) were installed, the brake system will also need to be upgraded - as an option, install a caliper for larger pads.
The appearance of an airlock; Depressurization of the circuit; Overheating and boiling of the TJ; Failure of the main or wheel brake cylinder.The pedal fails or becomes unusually soft.Bleed the brakes (how to do it correctly, Read here); Do not violate the TJ replacement procedure specified by the manufacturer; Replace the worn out element.
Damage to vacuum or burst of hoses; TC bushings are worn out.It takes a lot of effort to press the pedal.Repair a failed element or diagnose the line.
Brake pads wear out unevenly; Rapid wear of the brake cylinder elements; Depressurization of the brake line; Tires wear out to varying degrees (this manifestation rarely affects the brakes - the main reasons for uneven wear discussed in another article); Different air pressure in the wheels.When braking is in progress, the car is pulled to the side.Check the tire pressure; During replacement, correctly install the brake pads; Diagnose all elements of the brake system, identify a breakdown and replace the part; Use quality parts (buy from trusted suppliers).
Worn or damaged brake disc; Broken rim or tire wear; Improperly balanced wheels.Vibration is felt when braking.Balance the wheels; Check the rims and tire wear; Check the condition of the brake discs (if you brake urgently at high speed, the discs overheat, which can cause deformation).
Pads worn or overheated; Pads clogged; Caliper has moved.Constant noise when driving or its appearance every time when braking (squeak, grinding or squeaking); If the friction layer is completely erased, then during braking you will clearly hear the sound of rubbing metal parts and vibration in the steering wheel.Check the condition of the pads - whether they are dirty or worn out; Replace the pads; When installing the caliper, lubricate the anti-squeak plate and pins.
Breakage of the ABS sensor; Clogged brake caliper; Oxidation of the ABS sensor contacts or wire breakage; Blown fuse.In a vehicle equipped with ABS, the warning light comes on.  Check the operation of the sensor (instead of the suspected device, a known working one is installed); If clogged, clean; Replace the fuse; Diagnose the system control unit.
The handbrake is raised (or the parking system button is pressed); The brake fluid level has decreased; Failure of the TJ level sensor; Breakage of the parking brake contact (or its oxidation); Thin brake pads; Problems in the ABS system.If the machine is equipped with such a control system, then the Brake lamp is constantly on.Check the parking brake contact; Diagnose the ABS system; Check the brake pad wear; Check the brake fluid level; Be in the habit of checking the position of the hand brake before driving.

Pads and brake disc replacement intervals

Checking the brake pads should be done during seasonal tire changes. This makes it easier to diagnose wear on time. Unlike technical fluids, which need to be changed at regular intervals, brake pads are changed either in the event of a sudden failure (for example, due to debris, the friction surface has unevenly worn out), or when worn to a certain layer.

What you need to know about the brake system of a car?

To increase the safety of the brake system, many manufacturers equip the pads with a special signal layer (brakes squeak when the base layer has worn off). In some cases, the car owner can determine the wear of elements by color indication. The effectiveness of brake pads decreases when they are less than two or three millimeters thick.

Brake Prevention

So that the braking system does not break down abruptly, and its elements work out all the resource they are entitled to, you should adhere to the basic and simple rules:

  1. Diagnostics should be carried out not in a garage service, but at a service station with precision equipment (especially if the car is equipped with a complex electronic system) and in which specialists work;
  2. Adhere to the regulations for replacing brake fluid (indicated by the manufacturer - basically this is a period of once every two years);
  3. After replacing brake discs, active braking should be avoided;
  4. When signals from the on-board computer appear, you need to contact the service as soon as possible;
  5. When replacing components, use quality products from trusted manufacturers;
  6. When replacing brake pads, lubricate all caliper parts that need it (this is indicated in the operating and installation instructions for the mechanism);
  7. Do not use wheels that are not standard for this model, as in this case the pads will wear out faster;
  8. Avoid heavy braking at high speeds.

Following these simple guidelines will not only extend the life of the brakes, but also make any ride as safe as possible.

In addition, this video describes the prevention and repair of the car's brake system:

Questions and answers:

What kind of braking systems are there? Car braking systems are divided into: working, spare, auxiliary and parking. Depending on the class of the car, each system has its own modifications.

What is the car parking brake system for? This system is also called a hand brake. It is intended primarily to prevent a car from rolling back downhill. It is activated during parking or for a smooth start up a hill.

What is an auxiliary braking system? This system provides additional control of a constant vehicle speed during a long downhill (using engine braking).

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