The brake system is one of the key components of a car, on which the safety of the driver and passengers depends. Even the most powerful engine and advanced suspension will not save you if the brakes are ineffective. But how to understand the variety of braking mechanisms if manufacturers use different solutions for the front and rear axles, cars and trucks, sports and city models?
In this article we will look in detail all types of car brakes, their design, advantages and disadvantages. You will learn how disc brakes differ from drum brakes, why a vacuum booster is needed, how the anti-lock braking system (ABS) works, and why the electric parking brake is gradually replacing the mechanical one. We will also give practical advice on how to identify faults and when it is time to change brake pads or discs.
1. Main types of brake systems by purpose
Before delving into the design of specific mechanisms, it is important to understand that the braking system of a car is a complex of several subsystems, each of which performs its own function. Total allocated three main types according to purpose:
- 🔧 Working (main) - used to reduce speed and completely stop the car while driving. Activated by the brake pedal.
- 🅿️ Parking — keeps the car in place after stopping (for example, on a slope). Turned on by lever or button.
- 🚨 Spare (emergency) — duplicates the working system in case of its failure. In modern cars it is often combined with a parking lot.
In most passenger cars, the working system is hydraulic (with a booster), the parking system is mechanical or electromechanical, and the spare system is activated automatically when the pressure in the hydraulic drive drops. For example, in Volkswagen Golf or Toyota Corolla The spare system locks the rear wheels through the same cable as the handbrake.
Interestingly, it is often used in trucks and buses pneumatic braking system, where compressed air is used instead of liquid. This is due to the need to brake large masses with minimal driver effort. For example, in Scania R420 or MAZ-5340 the pressure in the pneumatic system reaches 8–10 bar.
2. Disc brakes: design and principle of operation
Disc brakes are the most common type for passenger cars today, especially on the front axle. Their popularity is due to their high efficiency and stable operation even under heavy braking. Structurally, the system consists of:
- 🛠️ Brake disc - a metal rotor mounted on the wheel hub. It can be solid or ventilated (with internal channels for cooling).
- 🔘 Calipers - a moving mechanism in which the brake pads are installed. It can be floating (single-piston) or fixed (multi-piston).
- 🧊 Brake pads - friction linings pressed against the disc. They consist of a base and a working layer (usually composite materials).
- 💧 Hydraulic drive - cylinders, hoses and brake fluid that transmit force from the pedal to the caliper.
When you press the brake pedal, fluid under pressure enters the caliper, the pistons extend and press the pads against the disc on both sides. The resulting frictional force slows down the rotation of the wheel. The harder you press, the greater the clamping force. In sports cars (eg Porsche 911 GT3 or Nissan GT-R) use ceramic discs and multi-piston calipers (up to 8 pistons), which provides record braking force.
Advantages of disc brakes:
- ✅ High heat dissipation (especially for ventilated discs).
- ✅ Stable operation during repeated braking (no fading - loss of efficiency due to overheating).
- ✅ Easy to replace pads and discs.
- ✅ Possibility of use in ABS and ESP systems.
Disadvantages:
- ❌ Higher cost compared to drums.
- ❌ Sensitivity to corrosion (discs rust when parked for a long time).
- ❌ Rapid wear of pads during aggressive driving.
If your brakes start squeaking after washing your car, don't panic - this is a temporary phenomenon due to moisture on the pads. After 10–20 km of driving, the sound will disappear.
3. Drum brakes: where are they used and why do they not disappear?
Drum brakes are considered an outdated solution, but are still used on the rear axle of many budget and compact cars (for example, Lada Granta, Renault Logan, Hyundai Solaris). Their main elements:
- 🥁 Brake drum - a cast iron or aluminum cylinder that rotates with the wheel.
- 👟 Brake pads — semicircular plates with friction linings that move apart inside the drum.
- 🔄 Working cylinder — a hydraulic mechanism that presses the pads to the drum.
- 🔗 Parking mechanism - a lever connected to the handbrake cable.
When you press the pedal, the cylinder pistons push the pads apart, which are pressed against the inner surface of the drum, creating braking force. Unlike disc brakes, friction occurs within an enclosed space, causing heat and reduced efficiency during heavy use (called "fading").
Why are drum brakes still installed?
⚠️ Attention: Drum brakes are absolutely not suitable for sport driving or towing heavy trailers. If they overheat, their efficiency can drop by 30–50%, which can lead to an accident.
| Benefits | Disadvantages |
|---|---|
| ✔ Low cost of production and repair | ✖ Difficulty in replacing pads (you need to remove the drum) |
| ✔ Good protection against dirt and moisture | ✖ Tendency to overheating and fading |
| ✔ Compactness (important for the rear axle) | ✖ Uneven pad wear |
| ✔ Can be combined with a mechanical parking brake | ✖ Difficult to integrate with ABS |
Recently, drum brakes are gradually being replaced by disc brakes even on budget models. For example, in Kia Rio 4th generation (since 2017) rear disc brakes began to be installed in top trim levels, and in Volkswagen Polo 6th generation they come in the database.
4. Parking brake: mechanical vs. electromechanical
The parking brake (or “handbrake”) fixes the car in place, preventing spontaneous movement on slopes. Traditionally, it was mechanical - with a lever in the cabin and a cable drive to the rear pads. However, in modern cars it is increasingly common electromechanical parking brake (EPB), which is activated by the button.
Mechanical "handbrake" it works simply: when the lever is raised, a cable is pulled, which, through a system of levers, pushes the pads in drum brakes or presses them against the disc (in disc systems with an integrated mechanism). Main advantages:
- ✅ Simplicity of design and low cost of repair.
- ✅ Possibility of use as a spare brake system.
- ✅ Does not depend on electronics.
Electromechanical EPB replaces the lever with a button, and instead of a cable, an electric motor is used, which presses the pads. Benefits:
- ✅ Automatic activation when the engine is turned off (in some models).
- ✅ Feature
Auto Hold— holds the car at traffic lights without pressing the pedal. - ✅ Compactness (no bulky lever in the cabin).
Examples of vehicles with EPB: Audi A4, BMW 3 Series, Skoda Octavia. However, such a system also has disadvantages:
⚠️ Attention: If the battery is discharged, the electromechanical parking brake may remain locked. In some models (for example, Volkswagen Passat B8) emergency unlocking is provided using a screwdriver through a special hole under the armrest.
How to unlock EPB when the battery is dead?
1. Connect the charger or light up the car.
2. If this does not help, find the emergency hatch (usually under the plastic plug next to the gearshift lever).
3. Insert a screwdriver and turn counterclockwise until it clicks.
4. After the engine starts, the brake will automatically enter operating mode.
5. Auxiliary braking systems: ABS, ESP and others
Modern cars are equipped not only with main brakes, but also with auxiliary systems that improve safety and controllability. The most common:
- 🚗 ABS (Anti-lock Braking System) — prevents wheel locking during emergency braking, maintaining controllability. It works using speed sensors and a pressure modulator.
- 🌀 ESP (Electronic Stability Program) — corrects the trajectory of movement during a skid, braking individual wheels and regulating engine power.
- 🔄 EBD (Electronic Brakeforce Distribution) — distributes the braking force between the axles depending on the vehicle load.
- 🚦 BAS (Brake Assist System) — increases braking force when pressing the pedal in an emergency.
- 🅿️ Hill Hold Control — automatically keeps the car on the rise for 2-3 seconds after releasing the brake pedal.
For example, in Ford Focus 3 system ABS fires at a speed of 15 times per second, and ESP can reduce engine power by 20-30% when skidding is detected. It is important to understand that these systems do not reduce braking distances on dry asphalt, but significantly improve control over the car in extreme situations.
How to check ABS operation?
Accelerate to 40-50 km/h on an empty road|Press the brake pedal firmly all the way|You should feel the vibration of the pedal and hear clicks|The car should brake without locking the wheels (no squeaking rubber)-->
6. Hybrid and innovative braking systems
Automakers are constantly working to improve braking systems. Among the latest developments:
- 🔋 Regenerative braking - used in hybrid and electric vehicles (for example, Tesla Model 3, Toyota Prius). When braking, the electric motor acts as a generator, converting kinetic energy into electrical energy and charging the battery.
- 🛡️ Ceramic brakes - installed on sports cars (Ferrari 488, Lamborghini Huracán). They can withstand temperatures up to 1000°C and weigh 50% less than cast iron.
- 🤖 Artificial intelligence brakes — are being developed for autonomous cars. The system analyzes the road situation and predicts the need to brake in advance.
Regenerative braking is especially effective in the city, where frequent stops allow up to 20–30% of energy to be recovered. However, such a system has a caveat: during heavy braking, traditional brakes are also activated, since recuperation cannot provide sufficient deceleration force.
Ceramic brakes, despite their advantages, still remain the prerogative of premium and sports models due to their high cost (a set of discs and pads for Porsche 911 may cost 15–20 thousand rubles).
7. Signs of brake system malfunctions
Any braking system requires regular maintenance. The following symptoms indicate that something is wrong with the brakes:
- 🔊 Creaking or whistling when braking - wear of the pads or sand getting between the pad and the disc.
- 🔥 Vibration of pedal or steering wheel — deformation of brake discs (often due to overheating).
- 💧 Pulling the car to the side — uneven wear of the pads or jamming of the caliper.
- 🛑 Increased braking distance — worn pads/discs or brake fluid leakage.
- 🚨 ABS or brake light is on — malfunction of sensors or drop in liquid level.
What to do if the brake pedal becomes “soft” or fails? This is a sign air entering the hydraulic drive or brake hose wear. In this case it is necessary:
- Check the brake fluid level in the reservoir (should be between
MINandMAX). - Inspect hoses and connections for leaks.
- Bleed the brake system to remove air.
⚠️ Attention: If after replacing brake pads or discs the brake pedal becomes stiff, this is normal - new parts require running-in (usually 100–200 km). But if the tightness persists longer, check the calipers for corrosion or seizing.
Check the thickness of the brake discs and pads regularly! The minimum permissible thickness of the disk is usually indicated on its end (for example, MIN TH=22 mm).
8. How to choose brake pads and discs: expert advice
When replacing brake pads or rotors, it is important to consider not only the price, but also their characteristics. Here are the key selection criteria:
| Parameter | Recommendations |
|---|---|
| Pad material |
|
| Disc type |
|
| Manufacturer | Give preference to brands ATE, Brembo, TRW, Ferodo. From budget - Bosch or Textar. |
Important: never install pads and discs from different manufacturers, unless they are certified for shared use. Different materials may cause uneven wear or reduced braking performance.
Also note friction coefficient (indicated on the pad packaging). Suitable for city driving 0.35–0.45, for sports - 0.5 and above.
After replacing the brake pads, avoid sharp braking for the first 200–300 km - this is the break-in time when the friction layer adapts to the disc.
FAQ: Frequently asked questions about brake systems
Is it possible to install disc brakes instead of drum brakes on the rear axle?
Technically yes, but this requires modifications to the suspension, installation of new hubs, calipers and changes to the hydraulic drive. In some models (for example, VAZ 2110) there are ready-made kits for such modernization, but for foreign cars this is usually impractical due to the high cost. Also don't forget to reconfigure ABS, if it exists.
Why do new brake pads squeak?
The creaking can be caused by:
- The material of the pads (ceramics or metal often creak).
- Sand or dirt getting between the pad and the disc.
- Lack of anti-squeak plates (sometimes people forget to install them).
If the squeak does not go away after 500 km, check the quality of installation or replace the pads with others.
How often should brake fluid be changed?
Brake fluid is hygroscopic - it absorbs moisture, which lowers the boiling point and leads to corrosion of parts. Recommended replacement interval:
- Regular fluid (DOT 3, DOT 4) - every 2 years or 40–60 thousand km.
- Low-Viscosity (DOT 4 LV, DOT 5.1) - every 3 years or 90 thousand km.
Check the condition of the fluid visually: if it becomes cloudy or darkened, replace it regardless of mileage.
Which is better: perforated or grooved brake discs?
Both types improve cooling, but have different features:
- Perforated — they remove heat and gases better, but wear out faster due to weakening of the metal structure.
- Notched - stronger, but less effective in extreme conditions (for example, on a track).
For everyday driving, ventilated discs are sufficient. Perforations or notches are justified only with an aggressive driving style.
Is it possible to drive if the brake pad wear indicator comes on?
A wear indicator (usually a metal tongue that rubs against the disc) signals that the thickness of the friction layer of the pads has reached a critical minimum (usually 2–3 mm). You can drive with such a signal, but no more than 500–1000 km — further the risk of damage to the discs and brake failure increases sharply. Also keep in mind that if the pads are completely worn out, the metal base will scratch the disc, which will lead to its deformation.