Main Components of Disc Brake

What Is Disc Brake?

When you are driving a car, your ability to stop fast is more important than how fast it can go. Safety is of utmost importance for any automotive manufacturer. At the heart of the vehicles, safety is the motor vehicle braking system. Commonly used braking systems are two: the disc brake system and the drum brake system.

Disc brakes are betters than drum brakes because they provide a more predictable response at high temperatures and in wet conditions. Disc brakes are less prone to brakes fade. Disc brake rotors rotate with the wheels, and brake pads, which fit on brake calipers, clamp on these rotors to prevent or damage the wheels.

The brake pads pushing against the rotors produce friction, which converts the kinetic energy into thermal energy. This thermal energy produces heat, but since the main components are in contact with the atmosphere, this heat can be diffused efficiently. This heat-dispersing property minimizes brake fade, which is the event where braking performance is affected by heat.

Another advantage of disc brakes is resistance to water fade, which occurs when the water on the brake significantly reduces braking force. When the vehicles are in motion, the rotor rotates at high speed, and it self-discharges water from the rotational speed rotors, resulting in a constant braking force.

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Main Components of Disc Brake:

Main Components of Disc Brake.

There are two types of disc brakes. One is called the “opposing piston type disc brake,” which has pistons on either side of the disc rotor, and the other is a “floating type disc brake” that has pistons on only one side. Floating type disc brakes are also called sliding pin type disc brakes.

#1. Wheel Hub

The disc rotor is attached to the wheel hub, and it rotates with it. The wheel of the vehicle is a bolt to the wheel hub.

#2. Caliper Assembly

  • Brake pad:- It makes contact with the rotor disc, and due to friction between the brake pad and rotor disc, the vehicle speed decreases, and it stops.
  • Caliper Bracket.
  • Caliper Frame.
  • Piston:- Brake force is applied to the brake pad by pressing the brake lever.
  • Slider Pin:- It is the sliding pin that slides into the hole when the brake is applied.
  • Dust shoes:- This prevents the entry of dust into the caliper pin or slider pinhole.
  • Disc rotor:- This is the rotating part of the disc brake. When the brakes are applied, too much heat is produced, which can reduce braking efficiency, so the rotor has drilled vent holes on it, which dissolve the heat.

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Working Principle of Disc Brake:

When the driver steps on the brake pedals, the power is amplified by the brake booster (servo system) and converted to hydraulic pressure (oil pressure) by the master cylinder. The pressure reaches the brake on the wheels through a tubing filled with brake oil (brake fluid). The distributed pressure pushes the piston on the brakes of the four wheels.

In turn, piston brake pads, which are friction materials, press against the brake rotors that rotate with the wheels. The pad mounts to the rotors from both sides and screws the wheels, slowing down & stopping the vehicle.

When the brake pedals are pressed, the high-pressure liquid from the master cylinder pushes the piston outward. The rotating disc prevents the piston brake pads.

The inner brake pad touches the rotor, fluid pressure increases the forward force, and the caliper moves inward and pulls the outer brake pad towards the rotating disc, and it touches the disc.

Now both brake pads are pushing the rotating disc. , A large amount of friction between the pad and the rotating disc is generated and slows the vehicle down and, ultimately allows it to stop.

When a brake pad comes out, the piston moves inward, the brake pad away from the rotating disc. And the vehicle starts moving again.

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Types of Disc Brakes:

Types of Disc Brakes.

There are two types of disc brakes. One is called the “opposing piston type disc brake,” which has pistons on either side of the disc rotor, and the other is a “floating type disc brake” that has pistons on only one side. Floating type disc brakes are also called sliding pin type disc brakes.

#1. Opposite Piston

The opposite piston type is a disc brake that has pistons on either side of the disc rotor.

In contrast, piston-type disc brakes have a stable braking force as well as a high degree of controllability. The flowing areas of the brake pads are enlarged to increase the braking force, and here opposing piston types are favored.

The reason for this is that its advantage where the number of pistons can be increased from both sides to realize the distribution of pressure on the rotors. Depending on the size of brake pads, there are several variants, including the 4-pot types, which have two pistons on each side for a total of four, & the 6-pot type that has three pistons on each side for totals of six.

#2. Floating

The floating type is a disc brake that has only one side piston and is also called a sliding type disc brake. On floating type disc brakes, the piston pushes the internal brake pads against the rotor when the brakes are engaged.

This produces a reaction force that moves the caliper with the slide pin, pushing the outer pad against the rotor and pressing it from both sides.

Many passenger car disc brake is of the floating caliper type as this type has a relatively simple & lightweight construction, which allows for low manufacturing costs.

Floating type disc brake for commercial vehicles Disc brakes are primarily used for passenger cars, but due to their consistent performance at high speeds & resistances to brake fade, they are gradually spreading to the commercial vehicle segment, where drum brakes traditionally wear out, Were elected for resistance against.

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Construction of Disc Brake:

Construction of Disc Brake

The brake rotor (disc) that rotates with the wheel is affixed to the brake pad (friction material), which is connected to the caliper from both sides with pressure from the piston (pressure) and slows down the rotation of the disc. , Which slows down and stops the vehicle.

#1. Rotor

The circular disc bolt to the wheel hub that rotates with the wheel. The rotors are mostly made of cast iron or steel; However, some very high-end cars use a carbon-ceramic rotor. Rotors can be sluggish or drilled for better heat dissipation.

#2. Brake Pad

The component that pushes into the rotor, which slows down friction and stops a car. They have a metal part called a shoe and a lining that attaches to the shoe. The lining is the one that actually comes in contact with the rotor and goes away from use.

The lining is made of different materials and falls into three categories: organic, semi-metallic, and ceramic. The chosen lining material will affect the length of the brake life, the amount of noise heard when the brake is applied, and how quickly the brakes stop a car.

#3. Sensor

Some vehicles have brakes that have sensors fitted to the brake pads that act to tell the driver when the pad is damaged. Other brake sensors play a role in the vehicle’s ABS system.

Disc brakes are commonly used in passenger cars, but due to their stable performance at high speeds & resistance to brake fades, they are gradually spreading to the commercial vehicle segment, where drum brakes have traditionally been used for their long time Till the service life was chosen. There are two types of disc brakes.

The “opposing piston type disc brake” has pistons on either side of the disc rotor, while the “floating type disc brake” has only one side piston. Floating caliper-type disc brakes are also called sliding pin-type disc brakes.

#4. Piston

The cylinder brake system is connected to hydraulics. The piston brake moves the brake to the rotor when the driver presses the brake pedal. Some brake systems have a singles piston that moves both pads, while others have a two-piston that pushes brake pads from each side of the rotor.

Others stills have four, six, or eight pistons for higher braking power, at the cost of additional cost and complexity.

#5. Calipers

Housing that fits on the rotor and holds brake pads and pistons, as well as ducting for brake fluid. There are two types of brake caliper: floating (or sliding) and fixed. Floating calipers “float” on the rotor and only have pistons on one side.

When the driver presses the brake, the piston presses the brake pad into the rotor on one side, causing the caliper to slide up so that the pads on the non-piston side of the caliper also contact the rotor.

Fixed calipers are mounted in place, and instead, there are pistons on both sides of the rotors that move when the drivers apply the brakes.

Fixes caliper applies brake pressure evenly and presses more firmly onto the rotor, although floating caliper is found on most cars & is perfectly adequate for everyday driving.

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Types of Rotor:

Types of Rotor.

#1. Smooth Rotors

The smooth rotor is identified by its flat, smooth surface. For most cars & trucks on the road, smooth rotors are basic equipment (OE) due to their versatility for many driving conditions.

The main advantage of smooth rotors is that they tend to wear evenly, allowing your brake pads to last longer. If you want to keep a smooth rotor but still go for an upgrade, look for premium metal that absorbs more heat.

#2. Drilled / Dimpled and Slotted Rotors

Rotors that are drilled (or dimpled) and slated, while effective, are best for trucks that want added beauty, such as with wheels that have a more open design. Not only will they look greats through an open-wheel, but drilled holes aid in initial cutting, while slots are designed to remove dust and debris from between the rotor and brake pads.

#3. Drilled or Dimpled Rotors

The drilled rotors are identified by the hole pattern that has been drilled all the way through the rotor disc. Dimensional rotors are similar, although instead of holes, there are dimples that are drilled to the minimum thickness level of the rotor, maintaining greater structural integrity than fully drilled rotors.

These rotors type help the brake pads to hold the rotor better, giving it more initial cutting and increased stopping power.

#4. Slotted Rotors

Slotted rotors are identified by the carved lines found on the rotor. These carved slots help cool the rotor during high-performance use. They help remove dirt and other debris from discs and brake pads and help maintain constant contact for more efficient braking. Slotted rotors are perfect for vehicles that often have heavy towing.

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Rotor Materials of Disc Brake:

#1. Cast Iron

This is the definition of the old school when it comes to the brake rotor. It slices one or two and gets the job done. In fact, it is the most commons material for brake rotors. The right design (usually two pieces) can also work well in a performance vehicle.

However, it is also the heaviest option, affecting the overall weight of your car and its handling, as this weight is with your front wheels.

#2. High Carbon

These are of iron but mixed with a lot of carbon. They can take too much heat and destroy it quickly. The metal material helps protect the rotor from breaking under high stress, and brake noise and vibration are also reduced. The only downsides are the prices, which are much higher than straight iron or aluminum.

#3. Ceramic

They offer the highest heat capacities (85 percent more than cast iron) and better dissipation, and they maintain a more consistent force & pressure as the temperature of the rotors increases. Ceramics are the highest-performance brake rotor available today.

#4. Steel

Steel has been a racer’s choice for years because a steel brake rotor is thinner, weighs less, and handles heat better. Downside: Steel rotors are not as durable as anything else, and deformed rotors can cause noise and vibratory paddles when you brake.

#5. Layered Steel

Laying steel sheets together and laminating them makes them resistant to war that can be found in a straight steel brake rotor. It is a favorite of racers, who do not want frequent brake rotor replacement and repair, but manufacturers are currently targeting only professional racers, and production is limited, so it is not very common in passenger vehicles application.

#6. Aluminum

Aluminum brakes rotor dissipate heat quickly, but they melt at lower temperatures than other alternatives. Aluminum is favorite for motorcycles, which weigh less and are easier on the rotor when applying brakes than heavy cars, trucks.

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Advantages of Disc Brake:

  • It is lighter than the drum brake.
  • It is better cooled (because the braking surface is directly exposed to air).
  • This provides better resistance to fade.
  • It provides uniform pressure distribution.
  • Replacement of brake pads is easy.
  • By design, they are self-adjusting brakes.
  • Replacement of brake pads is easy.

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Disadvantages of Disc Brake:

  • It is more expensive than drum brakes.
  • High pedal pressure is required to stop the vehicle. This brake system is installed with a
  • Vacuum booster.
  • There is no servo action.
  • A suitable parking attachment is difficult to attach.


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