Most vehicles have different braking systems. If you have disk brakes, you can peer through the hubcap of your vehicle’s front wheel, and see a shiny metal disc. A pad consisting of a hard-wearing material clamps onto the brake disc and rubs it to make it slow down once you step on the brake pedal.
Some vehicles have disc brakes on all wheels while others have drum brakes on the back wheels. Drum brakes have shoes inside the hollow wheel hub that presses outwards. As the shoes push into the wheel, friction is what slows you down.
Your car also has a handbrake or as some call it, your emergency brake. When you pull this handbrake, it applies the two rear brakes (disc or drum) in a slower and less forceful way.
When you try to stop a speeding car, the energy from the car when you stop is converted into heat in the brake pads. These brakes can heat up to temperatures of 950⁰F or more. That is why brakes are made of materials that won’t melt such as alloys, ceramics, or composites.
Brakes use hydraulics which is a system of fluid-filled pipes that multiply force and transmit it easily from one place to another. Pressing your foot pedal would not generate enough force to apply all four brakes hard enough to bring you to a quick stop.
How Brakes Work
- Push the brake pedal.
- While the pedal moves down, it pushes a lever increasing your pushing force.
- This lever pushes a piston into a narrow cylinder that is filled with hydraulic brake fluid.
- While the piston moves into the cylinder, it squeezes hydraulic brake fluid out of the end.
- Brake fluid squirts down a long, thin pipe until it reaches another much wider cylinder at the wheel.
- Once the fluid enters the cylinder, it pushes the piston into the much wider cylinder with increased force.
- The piston pushes the brake pad toward the brake disc.
- Once the brake pad touches the brake disc, the friction between the two generates heat.
- The friction is what slows down the outer wheel and tire, which stops your vehicle.
Your brake pedal operates four separate hydraulic lines running to each of the four wheels.