How do Disc Brakes work

How do Disc Brakes work

How do Disc Brakes work in cars ⏩ Working principle of braking system in automobile ✅ Components and functions of Disc Brake ☝

Most of the modern-day cars use disc brake system. They are called so because of the fact that it uses force applied to discs attached to wheels to slow down or stop the vehicle. As compared to drum braking systems, they offer great stopping power and do not overheat quickly under heavy use. Some of the entry-level cars still use drum type stopping systems at the rear end. Its working looks simply but has a complex role to play. Every braking system comes with sensors to warn the owner about the need for replacement of pads or any other component.

If you are one of those who wants to know how these braking systems work in motorcycles, then look no further. The fact is, no matter whether you want to know how disc brakes work in bike or motorcycle, the answer would be same as the way how it works in a car.


The hydraulically operated disc brake works on the basis of Pascal’s law of operation. As per it, the pressure exerted anywhere in a confined incompressible fluid is transmitted equally in every direction in such a way that pressure remains the same. A component-based on this principle is used to multiply the forces, which is what braking does.


We all know that that force we applied to the pedal is not sufficient to stop all the wheels, hence pedal is given. When you apply pressure on a pedal, the hydraulic system multiplies the force and transmits it to the pads. In general, the rely on the friction to the vehicle. When the pedal is pressed, the force is generated with the help of booster and sent to the pistons. The piston then pushes pads against the rotor and create friction to slow or stop the vehicle.  The kinetic energy of the car is then converted into heat. There are several types of disc brake brands available in the market.

Components of Disc Brake

Every disc system comprises of mainly five parts, which are explained below:

  • Rotor: These are circular discs bolted on the wheel hub which helps to spin the wheel. These are made up of steel or cast iron, while high-end cars use carbon ceramic rotors. These can be drilled for better heat dissipation.
  • Brake Pads: Another component that makes up the disc braking system in automotive is brake pad. It is an automotive component that pushes into the rotor, which as a result creates friction to slow or stop the vehicle. It has a metal portion called shoe and has a lining attached to it. The lining comes in contact with the rotor and wears away after use. Linings are made of three different materials – organic, ceramic and semi-metallic.
  • Piston: In every automotive, a cylinder is connected to stopping system hydraulics. The piston is responsible to move pads to the rotor every time a driver presses a pedal. Some of the brake systems have a single piston that moves both pads while others have two pistons to push pads from each side. The vehicle can have more pistons for higher braking power which are largely found in sports cars.
  • Calipers: These are housing that fits over the rotor and holds piston and pads at the same time contain ducting of brake fluid. There are two types of calipers available  - floating and fixed. Floating calipers, as the name, suggests floats over the rotor and have pistons on the single side. While fixed calipers are bolted at a fixed place and have pistons towards both sides of the rotor.

Disc Brake’s functions

Ideally, the vehicle should stop immediately. As soon as the driver presses the pedal, pistons pressurize the hydraulic fluid in brake lines. The brake lines movies piston and pushes pads into the rotor. This means, harder the driver pressurizes the pedal, greater will be the pressure in the lines, and the brake pads will squeeze the rotor. The distance that pads move is small and should retract back as soon as the driver lets off the pedal.

Maintenance and Troubleshooting

It is always a good idea to inspect pads and rotors for excessive wear on a regular interval. The repair shop near you can do a complete inspection and can repair or replace them as a need arises. It is recommended to get it inspected during the oil change. This will give you safety and will eliminate the potential risk of high-cost repairs. Keeping the brake system in a good condition is always helpful as it can save you from hitting others. Moreover, you can find videos and trailers online to take care of braking system.

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