How Does a Car Brake System Work?

Car owners look at the beast machinery as a means of transport; something that gets you from one point to the other. It is only when you encounter trouble or have a flat tire or a heating engine in the middle of the road, do we acknowledge the brilliant mastermind that has gone into making this machine, into a comfortable, functional vehicle. 

I am sure curiosity got the better of us someday, and we have all wondered how a certain part of the car works. Whether it is the steering, or the wheels, or the brake, this complicated machinery and its smooth running seems nothing short of magic. And yet, it is all science!

In this article, we will be taking an in-depth look into how does a car brake system works. It’s wonderful how such a heavy vehicle comes to a straight halt with just some pressure on the pedals. Let’s see how this is done. 

Hydraulics – How does it work?

When a vehicle is moving and you suddenly jam the brake, it comes to a halt because of a hydraulic system – which is basically using pressurized liquid to generate power. To comprise the working of a brake, it essentially means to use friction, which is produced by kinetic energy, to bring the machine to an abrupt halt. 

Before we get into a more complicated outlook and jargons, let’s first see how hydraulics work. 

The primary reason to use a hydraulics system is that liquid cannot be compressed. When you think about it, you are never able to compress liquid in a sealed chamber; it will just escape from all sides and go another way. Similarly, when you squeeze a plastic bottle, you’re not compressing the liquid, it’s only the poor bottle that is taking the load, that too till a limit. After a point of time, you will not be able to further squeeze the bottle. Hydraulics stops you from collapsing the bottle. 

And if the cap is not tightly secured, the water escapes the bottle, as the hydraulic pressure shoots it right out. This is how the brake system works.

Let me explain further. 

Hydraulics Brake – How it works?

The car brake system consists of many parts which include the pedal, the master cylinder, callipers, rods, etc. Let’s see how they are connected.

The brake pedal is connected to the master cylinder via a metal rod. The master cylinder plays an important role in how your car brakes work. The brake fluid is contained in the master cylinder. which is a completely sealed chamber. The brake fluid acts as hydraulic oil and the brake lines connect the master cylinder to the brake callipers. These brake lines are then used as passageways through which the brake fluid flows. 

So, what happens when you press the brake pedal?

The metal rod, which is attached to the master cylinder works on a piston which is placed inside the master cylinder. The job of the piston is to compress the brake fluid thereby leading to a pressure built up in the brake system. This pressure is then carried through the brake line with the brake fluid, which then provides enough friction and force needed to ‘brake’ the car. Naturally, the more pressure that goes into the pedal, the more force will be transmitted to stop the car. 

This whole system works backwards when you release the pressure from the brake pedal. The piston in the master cylinder is released using a spring action, thereby decompressing the fluid. This allows your brake to be free of pressure and ready to move again. 

| Also Read: Car Brake Fluid Check: Which Brake Fluid is Best for your Car? |

Callipers – What do they do?

Whenever someone talks about a car braking system and how it works, there is always a mention of callipers. Every vehicle braking system has a component called calliper which is placed behind each wheel. When the pressure reaches the calliper through the brake fluid and brake line, it makes use of a clamping force. This forces the brake pads against the brake disc, which generates enough friction to bring the car to a halt. 

Let’s look at it again; you press on the brake pedal, the master cylinder does its work and the brake fluid passes through the brake lines, creating hydraulic pressure. This reaches the callipers which pressurize the brake pads against the brake disc, creating friction and stopping the vehicle. 

In some particular vehicles, especially the old ones, callipers may be replaced with what is called brake drums- but their basic function is similar. 

Brake Pads and Brake Discs – What role do they play?

I am sure you have a fair knowledge about how does a car brake system works, but let’s look at two other essential parts of the braking system that play a huge role in stopping the car. 

So far, we know that when we press on the brake pedal, the hydraulic pressure is generated in the master cylinder, through which it passes to the brake lines. This pressurises the calliper to clamp down and create friction. Let’s simplify this by adding two more parts – Brake pads and brake discs(also known as brake rotors). 

Brake pads are essentially metal plates with a piece of friction material attached to them. Each calliper makes use of two brake pads, one on each end of the calliper. However, the brake pads are installed ensuring that the friction material of both the pads faces one another. There is a gap between the friction material, where the brake disc or rotor is placed. 

The brake is a round, flat, smooth metal disc that is attached to the vehicle’s wheel, turning with the same speed as they do. The calliper slips over a portion of that spinning brake rotor. We have the brake pads that are hovering above the rotating surface of the disc. 

When the hydraulic pressure is generated, it is transferred to the callipers which perform the clamping action. This brings the two friction surface sides of the braking pads together, thereby pressing against the spinning brake disc from both sides. This helps reduce the speed of the brake rotor, and therefore the tyres using heat and friction.  

This brings us to the end of our article explaining how does a car brake system works. For more such articles, keep watching this space.

If you have any questions or doubts, feel free to comment below.