An efficient braking system is essential for road safety. How do brakes work on a lorry? This issue is crucial for every professional driver, as the braking system in heavy goods vehicles differs significantly from that in passenger cars. Heavy goods vehicles, weighing up to several dozen tonnes, require much more efficient braking systems that can stop such a huge mass in a safe and controlled manner. Understanding how these systems work will not only allow you to drive more safely, but also to diagnose potential problems more effectively.
From this article, you will learn:
- What type of brakes are fitted to a lorry – specifications
- Types of brakes in lorries – an overview
- How truck brakes work – the basics
- How to maintain a lorry’s brakes – basic guidelines
- How do truck brakes work? – Modern brake assist systems
What type of brakes are fitted to a lorry – specifications
Modern lorries use advanced braking systems that differ significantly from those in passenger cars. The main difference is the use of air instead of hydraulic fluid as the medium for transmitting braking force. In lorries, you will find the following components of the braking system:
- air compressor – generating pressure in the system;
- air tanks – for storing compressed air;
- control valves – regulating air flow;
- brake cylinders – which convert compressed air energy into mechanical force;
- drum or disc brakes – actuators.
What kind of brakes are in a lorry? Air brakes are the most common type, offering high performance and reliability even under heavy loads.
Types of brakes in lorries – an overview
The braking system in modern lorries consists of several interacting systems, each of which performs a specific function.
Service brake
This is the basic braking system activated by the brake pedal. It acts on all wheels of the vehicle and trailer. When the pedal is pressed, compressed air flows to the brake cylinders, which activate the braking mechanism on the wheels. It is worth remembering that with regular use, truck parts, components such as brake pads and discs are subject to natural wear and tear and need to be replaced periodically.
Parking brake (emergency)
This type of brake is used to immobilise the vehicle when stationary or as an emergency brake in the event of a main brake failure. The parking brake works in the opposite way to the service brake – it is released by compressed air and activated by springs once the system has been vented.
Engine brake and retarder
These are auxiliary braking systems that reduce wear on the service brakes during long descents:
- engine brake – uses the engine as a braking element;
- retarder – a hydraulic or electric auxiliary system that enhances braking performance without the use of mechanical brakes;
- intarder – a type of retarder built into the gearbox.
Many modern SCANIA and DAF vehicles have advanced retarders, which are inspected SCANIA service and DAF servicing during regular checks.
How truck brakes work – the basics
How do a lorry’s brakes actually work? The pneumatic system of a lorry operates on several principles:
- An engine-driven compressor generates compressed air.
- The air is stored in tanks (front, rear and trailer circuits).
- When the brake pedal is pressed, the main valve releases air to the appropriate circuits.
- The compressed air reaches the brake cylinders.
- The cylinders convert the air pressure into mechanical force acting on the wheel brakes.
Modern lorries are equipped with advanced electronic systems such as ABS, EBS and ESP, which significantly increase safety and braking efficiency. With intensive use, DAF parts i SCANIA parts, they require regular checks and replacement to ensure the reliability of the braking system.
How to maintain a lorry’s brakes – basic guidelines
Proper maintenance of the braking system is essential for the safe operation of a truck. Here are a few rules for taking care of your truck's brakes:
- Check the system pressure regularly – it should be at least 6.5–8 bar;
- check the condition of the cylinders, hoses and connectors for leaks;
- Check the thickness of the brake pads – they should wear evenly;
- pay attention to unusual noises during braking;
- keep the brake system components clean.
How to care for truck brakes to maximise their service life? The key is regular diagnostics and servicing by specialists who have the right tools and knowledge.
How do truck brakes work? – Modern brake assist systems
Modern lorries are equipped with advanced electronic braking assistance systems, such as:
- ABS (Anti-lock Braking System) – prevents the wheels from locking during braking;
- EBS (Electronic Braking System) – electronically controls the braking force on individual axles;
- ESP (Electronic Stability Programme) – improves the vehicle’s stability when braking in a bend;
- ASR (Anti-Slip Regulation) – prevents the drive wheels from slipping.
The types of brakes in a lorry and their electronic assistance form a complex ecosystem that requires professional maintenance and regular inspections. The braking system is one of the most important safety systems in your lorry. Its proper functioning can determine not only your life, but also the lives of other road users. Regular inspections, professional servicing and the use of original spare parts are an investment in the safety and reliability of your vehicle.