What Are Disc Brakes Made Of?

Most vehicles nowadays have a disc brake system. But do you know what are disc brakes made of? How much maintenance do they need? Let’s find out.

The braking system is a critical component of any vehicle. Most four-wheelers these days are equipped with disc brakes, and it is usually attached to the front and back axle of the vehicle. The disc brake system mainly consists of a brake pad, a rotor, and a piston assembly commonly known as a brake caliper. 

You might be aware of these basics, but very few know the answer to the question: “what are disc brakes made of?” 

Usually, the disc is made of cast iron, but in a few cases, it is made from a combination of carbon or ceramic as well. Cast iron is less expensive and lasts relatively longer. Most sports cars use carbon discs and are paired with ceramic brake pads. 

These are very effective at stopping the vehicle when driving at a higher speed. However, these are a bit expensive. In this article, let us look in detail at the disc brake components and how to maintain the parts.

 

What Are Disc Brakes Made Of

 

Basics About The Braking System Of The Vehicle

Disc brakes use hydraulic pressure. A vehicle’s brake system requires a mechanical force to stop the vehicle safely. 

  • The piston squeezes the brake fluid inside the cylinder placed under the car’s hood beside the engine bay. Hydraulic pressure is created, and a large force is generated,
  • The brake pressure is shifted through the brake fluid using the brake hose and brake line that joins the brake lines along with the assembly of each wheel.
  • The wheel cylinder, which is one of the components of the brake system, presses the brake against the rotor to stop or slow down the vehicle. 
  • The disc brake assembly is specially designed to stop the vehicle when it gets activated.
  • Some vehicles are equipped with drum brakes. It also helps stop the vehicle when it gets activated.

 

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Disc Brakes

Nowadays, most vehicles are equipped with disc brakes. It is attached to the front and rear axle of the vehicle. The disc brakes use brake calipers that are attached to pads to hold down the spinning disc to slow down the car.

Components Of A Disc Brake System

#1 Brake Rotors

The brake rotors are built from cast iron or steel iron. It is connected to the wheel hub to spin the wheels, providing a surface to slow down the vehicle. 

Do you know how the rotors work? The brake fluid propels the pistons and forces the pads opposing the rotors when you hold down the brakes. As the pads are pressurized against the discs, friction is created to slow down the vehicle, dissipating heat from friction.

#2 Brake Calipers

A brake caliper is attached to the vehicle using a bracket. It is placed at the rotor edge and holds the brake pads. The calipers are attached to the brake lines and transform the hydraulic pressure to move with the piston. The piston presses the pads opposing the rotor, slows the vehicle, and generates heat.

The brake caliper mainly consists of the following parts:

  • Brake pads are connected to the metal plate that helps slow down the vehicle using friction.
  • It contains one or more pistons to press the brake pads against the brake disc or rotor while using the brake.
  • A bleeder screw helps replace the brake fluid or get the brakes serviced.
  • A rubber piston seal help stop the fluid from leaking and pulls back the piston when the driver releases the brakes.
  • A dust boot helps remove the dirt or other contaminants from the wheel cylinder.
  • The anti-rattle clips help provide stability.

 

What Are Disc Brakes Made Of

 

So, What Are Brake Calipers Made Of?

The disc brake calipers were traditionally made of ductile iron. Nowadays, most of the calipers are converted to aluminum. It is relatively lightweight, and the brake pads must be made from good quality materials to handle extreme road conditions.

  • Cast Iron. Earlier, most of the manufacturers used to make calipers with cast iron as it meets all the necessities of the brake system of any vehicle. It is pretty robust, cost-effective, and stress-resistant, and it does not rust if the proper coating has been done. It is designed to last a lifetime and rarely needs replacement.

Though cast iron lasts longer, it is relatively heavy, adding weight to your vehicle. So manufacturers started using aluminum to build brake calipers.

  • Aluminum Calipers. Aluminum calipers are stress-resistant, rust-resistant, and pretty strong. It is a great replacement for cast iron material, and it is relatively lightweight and reduces the weight to up to 40% of that of cast iron weight. This further enhances the ride quality and fuels the economy. 
  • Thermoplastic Material. Some vehicles use calipers made from thermoplastic material backed with carbon fibers. This material has a temperature resistance of 200° C and is lighter than aluminum.

 

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#3 Brake Pads

When the driver uses brakes, the brake pads hold down the surface of the rotors and create friction. This transforms the kinetic energy into heat and stops the vehicle. The brake pads are made from different types of materials. 

What Are The Different Types Of Brake Pads?

When you want to replace your brake pads, you will find various brake pads on the market. Each material has its specifications and characteristics, and you can choose the material that best fits your vehicle. 

Semi-Metallic

This type of brake pad uses around 35% to 65% metal. It is known to be pretty durable and has excellent stopping power. It dissipates heat efficiently. However, it may not work well in extreme road conditions and in low temperatures. The semi-metallic pads are cheaper and easier on the vehicle’s disc than the ceramic ones, but they can be noisy and contaminate more dust than the ceramic pads. This type of pad is not suitable for street driving and is mainly used in high-performing vehicles.

 

What Are Disc Brakes Made Of

 

Ceramic

The ceramic brake pads are expensive but have excellent stopping power. It dissipates heat pretty well, and does not produce a lot of noise like other materials, and is durable. These pads are built to last longer than the semi-metallic material. The ceramic pads perform well even in high temperatures. 

Non-Asbestos Organic

These types of brake pads are usually made from organic materials such as glass, fiber, Kevlar, and rubber. 

These materials do not pollute when they lose friction and are relatively softer than other brake pads, making them less noisy, but they may wear out faster and contaminate more dust. These types of brake pads are ideal for light vehicles that do not need hard braking. 

It works great in low temperatures, but you may experience inferior braking in high temperatures. 

 

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Types Of Disc Brakes

There are mainly two types of disc brakes: Fixed and Floating.

Fixed Brake Design

A fixed brake design uses one or more pistons attached to the sides of the rotor, and it is tightly fastened to the caliper bracket and does not move. The caliper piston moves and squeezes the brake pads opposing the disc when the drives press the brakes. 

Floating Brake Design

It uses one or two pistons only. The piston is placed only on one side of the rotor. Here, when the driver applies the brakes, the interior brake pads are pressurized against the disc, and the caliper moves near the rotor. This pressurizes the outer part of the brake pad opposing the rotor.

 

What Are Disc Brakes Made Of

 

Drum Brakes

In most vehicles, drum brakes are used on the rear axle. You will find it mostly in trailers. Many manufacturers do not use brake pads for friction. Instead, the drum brakes come with a wheel cylinder and piston that presses the brake shoes against the drum. This helps slow and stop the drum and wheel rotation from stopping the vehicle. 

What Are Brake Drums Made Of?

Usually, the drums are built from steel, cast iron, or aluminum. The brake drums constructed with aluminum have better heat dissipation. 

 

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Disc Vs. Drum Brakes

Most vehicles nowadays use disc brakes, and some models may still have drum brakes on the back wheels and disc brakes at the front.

Do you know why disc brakes are always in the front? This is because of the weight issue. When the vehicle is unloaded, it is 10% heavier at the front due to its engine. When you push the brakes, the car weight is transferred to the front, needing more braking power. So having disc brakes at the front is the most suitable option.

How To Maintain The Brakes Of Your Vehicle?

When you press the brakes, a lot of heat gets generated. This is because kinetic energy is converted to thermal energy (heat), causing high temperatures in other brake components. So even in normal driving conditions, there may be wear and tear on brake components which will need replacement. This includes replacing:

Brake Pad Friction Material

The brake pads may slow down the rotor via friction and wear out even after regular use. Gradually, it may become thin and will not function properly. The friction material can get damaged. So it is essential to keep a check on the brake components regularly as to prevent any wear and tear that may result in damaging other parts of the vehicle. 

Brake Fluid

It is essential to check the brake fluids and look for any leakages. When you get your brakes serviced, always replace the fluids in a few years. 

Any leakages in the wheel cylinder, brake fluid reservoir, or a hose will lower the hydraulic pressure when the brakes are pushed to stop the vehicle. If your brake cannot generate force, you will find that you need to press hard to stop your vehicle. 

So it is essential to change the brake fluid every few years when your brakes are serviced. Brake fluid helps prevent corrosion on the brake components; heat and moisture reduce the boiling point of the brake fluid. 

 

What Are Disc Brakes Made Of

 

Brake Hose And Lines

One of the essential components of a braking system is the lines and hose. A rubber hose may wear out, while the brake lines can rust over time. When anything like this happens, it reduces the efficiency of the brakes and lowers the hydraulic pressure. 

You may even find your vehicle getting pulled from one side. So it is essential to check the brake hoses and lines regularly to avoid any such problems.

Brake Rotors

It is essential to inspect the brake rotor and look for any wear and tear, damage, or cracks from heat. These things can reduce the braking power. It is better to replace the rotors when you get your brakes serviced. But if you find any such issues, you need to get it repaired soon.

Dust Boots

The brake components get contaminated with road dust and debris often. Having a dust boot helps prevent the dust from entering the brake calipers. But if it fails and does not prevent the dust from getting inside the caliper, it can damage the piston, and the brake may get damaged or wear out prematurely.

 

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How Often Should You Get Your Brakes Serviced?

There is no specified frequency as such. Getting your brake components repaired or serviced depends on the vehicle, climate, road condition, and driving style. However, get it checked regularly to make sure the brakes are functioning correctly.

Frequently Asked Questions

#1. Are Disc Brakes Made Of Aluminum?

Traditionally, disc brakes were mainly made of cast iron. But now, most manufacturers use aluminum as it is 40% lighter than iron and is much more efficient. It is relatively more durable and does not require regular replacements of components. 

#2. What Steel Is Used For Brake Discs?

Most of the brake discs are built with cast iron. The brake discs are made from ceramic or carbon-carbon composites in some vehicles. These parts are attached to the vehicle’s axle or wheels.

 

What Are Disc Brakes Made Of

 

#3. What Material Is Best For Disc Brakes?

The disc brake pads made from ceramic have excellent stopping power. It dissipates heat well and is ideal for street-driven cars. It operates quietly, produces less dust, and lasts longer. 

 

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A Few Final Words

The vehicle’s brake system comprises various components that include calipers, pads, and rotors. Most cars today are equipped with disc brakes. Usually, the disc brakes are made from cast iron which is less expensive and durable. 

While in some cases, carbon or ceramic mix composites are also used. You can replace your brake pads for better performance as per your driving style and vehicle use. 

Thank you for reading the article. We hope you liked the information that we shared here and we were able to answer your questions.