Brake Parts Explained

How much do you really know about brakes? And how do you know when they need repaired? The modern brake system is composed of many parts, and each has its own function, lifespan and sign that it needs to be replaced. Whether your car has disc brakes or drum brakes, if you don't maintain them, there's a chance your brake system could fail on you — which could be costly.

Fortunately, we're here to help. From brakes and rotors to pads, callipers and more, this article explains all the major parts of your brake system and when to replace them.

Brake Discs

What they are: Sometimes called brake rotors, sometimes called discs, this brake part is one of the main components of disc brakes. When brake pads press against the disc/rotor on each side, it causes the system to slow down or stop.
When to replace: The surface is where this brake part wears down. Over time, grooves or ridges can develop where the brake pads press down on them. If the brake pads can't maintain an even contact surface, you may experience grinding, meaning it's time to resurface or replace the rotors or discs. It's recommended to replace brake rotors/discs in pairs.

Brake Pads

What they are: Also a component in disc brakes, brake pads press on the brake rotors/discs to slow them down. They sit in the brake callipers and are activated by brake pistons.
When to replace: Squealing is a good indicator that there is an issue with your brake pads. Many cars have a brake warning sensor that lets you know when it's time to get your brake pads checked immediately. The best brake pads for your vehicle are often determined by your vehicle's owner's manual, or you may try searching online forums for a second opinion.

Brake Callipers

What they are: Callipers can be floating or fixed, and they house the brake pads, brake pistons and brake fluid. Think of them like a clamp. They're crucial for creating friction that slows down your brake rotors or discs.
When to replace: The main issue that pops up with brake callipers is with their seals, which can break down due to the heat in the brake system. But there can also be grinding due to the disc and calliper rubbing together. Get your callipers checked with the rest of your brake system every 12,000 miles.

Brake Pistons

What they are: Pistons press against brake pads to create friction on the brake rotors/discs. They're activated by brake fluid and sit within the brake callipers. There are usually one or two pistons per brake, but there can be more than one pair.
When to replace: If the brake is sticking or your car is leaking brake fluid, it could be a sign that brake pistons need to be replaced. More often than not, it's another brake component issue, which is why a brake inspection is so important.

Brake Drums

What they are: A crucial component in drum brakes, these drums are hollow and turn with the wheel. Unlike disc brakes, however, drum brakes are slowed down by brake shoes instead of brake pads.
When to replace: Drums are more prone to fading than discs and can fade faster if you apply them extremely frequently. If there is shaking, pulling to one side or loud noises when you are braking, it's time to get them checked out, as that's an indicator of a needed brake repair.

Brake Fluid

What it is: Brake fluid activates the brake pistons, which cause the brake pads to slow the car. Without enough brake fluid, the pistons won't activate properly to apply the pads to the discs and rotors.
When to replace: It's recommended to flush your brake fluid and replace it with new fluid every 20,000 miles or two years.

Brake Lines

What they are: Your brake fluid travels from the master cylinder to the wheels via brake lines. These are often made from stainless steel and rubber.
When to replace: It's often best to replace the entire brake line instead of repair it. If you notice leaking brake fluid, the line may be at fault, so it's a good idea to get a brake inspection.