What Are Calipers On A Car : Diagram, Types, Symptoms & Replacement Cost

What Are Calipers On A Car

Disc brakes are being used in modern vehicles. Because disc brakes are more effective than older technology and have more power, Disc brakes are capable of slowing or stopping the vehicle suddenly. Various parts are used in disc brake systems. Such as rotors, pistons, master cylinders, brake pads, and calipers. Brake calipers are a vital component in the braking system of modern vehicles.

Through this article, we will discuss brake callipers in detail, such as: what are brake callipers, how do they work, symptoms of bad brake callipers, and how much does a replacement cost?

What Are Calipers On A Car?

A brake caliper is an important part of a car’s disc brake system, which is used in the front brake system of most cars. The brake calipers act by squeezing the brake pads opposite the rotor, causing the brake calipers to create friction with the brake pads opposite the disc rotor, slowing the car or bringing it to a complete stop when the driver applies the brakes.

Brake caliper piston housings, often made of cast iron or aluminum, are located on the wheel hubs of a vehicle. Brake calipers work based on brake fluid pressure. Brake calipers have pistons and brake pads mounted on either side of the rotor.

How Does Brake Caliper Work?

When the brake pedal is pressed by the driver to slow the car down or come to a complete stop, brake fluid pressure is transmitted by the brake master cylinder to all of the car’s disc brake calipers through separate pipes mounted on the master cylinder assembly.

The pressurized brake fluid exerts pressure on the pistons of the calipers, causing the brake calipers to compress and the brake pads on either side of the rotor between the brake calipers to be squeezed onto the rotor, causing friction between the brake pads and the rotating rotor to occur with greater force And the wheels of the car start to slow down, and the rotor comes to a complete stop at a certain point in time when the driver continuously presses the brake pedal.

When the brake pedal is released, the fluid pressure drops, and the brake fluid travels back through the master cylinder to the reservoir tank. When the brake fluid pressure drops, the caliper pistons return to the same position, causing the brake pads to release their grip on the rotor and the wheels free to spin.

Brake Caliper Diagram – Parts

brake caliper diagram

Caliper Body

The main structure of the caliper is designed to house and provide structural support to other components of the brake system and is fitted with a hub knuckle, allowing the caliper to be positioned on either side of the rotor.


The brake hydraulic pistons are located inside the caliper body and are made of metal composite material. When hydraulic pressure is applied when the brake pedal is pressed, the pistons extend or retract to push the brake pads against the brake rotor.

Brake Pads

Brake pads are friction material attached to metal plates located on both sides of the brake rotor. When the pressure on the piston increases when braking, the piston squeezes either side of the brake pads and causes friction with the brake rotor.

Caliper Mounting Bracket

The caliper is mounted on a bracket, which is attached to the vehicle’s suspension or steering knuckle. The bracket provides stability to the brake caliper and keeps the caliper properly aligned with the brake rotor, preventing movement of the caliper during braking.

Guide Pin

The guide pins or bolts allow the caliper to move freely, ensuring equal pressure on both sides of the brake rotor. They are important for maintaining proper brake function and preventing uneven wear on the brake pads.

Brake Fluid Hose

The brake hose connects the caliper to the hydraulic lines of the brake system. When you press the brake pedal, hydraulic pressure from hydraulic fluid through the brake hose reaches the piston, causing pressure to build up in the caliper and actuate the piston.

Bleeder Valve

The bleeder valve is a small screw on the caliper that allows air to be released from the brake system’s fluid lines. It is used during brake fluid bleeding procedures to ensure that there is no air trapped in the brake lines.

Types of Brake Calipers

Generally, there are three types of brake calipers often used in the braking systems of car’s.

  • Single piston caliper
  • Dual Piston Clipper
  • Four Piston Caliper

1. Single Piston Caliper

single piston caliper

This type of brake caliper has only one piston. This piston is located exactly in the middle of the brake caliper. This piston alone squeezes the brake pads onto the rotor. Due to which the brake pads make their grip on the rotating rotor. The increased friction between the brake pads and the rotor causes the rotor to slow or stop completely, depending on the driver’s handling.

2. Dual Piston Caliper

dual piston caliper

This type of caliper uses two pistons in the braking system of vehicles. These pistons are located on the top of the brake caliper at both extreme ends. These two pistons of the brake caliper squeeze the brake pads on both sides of the rotor when the brake pedal is pressed by the slicker. This results in a greater force of friction between the brake pads and the rotor, and the vehicle slows down or comes to a complete stop.

3. Four Piston Caliper

four piston caliper

Four-piston calipers are also used in the braking systems of some racing cars and heavy vehicles. This type of brake caliper has two pistons on one side and two pistons on the other side as well. This type of caliper squeezes the brake pads onto the rotor with excessive force.

What Is Rear Calipers Brakes?

The rear brake caliper is a vital component in vehicles that have disc brakes in the rear brake system. The rear brake caliper is installed on the rear axle. The brake caliper on the rear wheel has pistons that, under hydraulic pressure, push the brake pads against the brake rotor, creating friction and slowing the vehicle. The rear brake caliper is installed on the rear wheel assembly by a mounting bracket, and guide pins ensure proper alignment of the caliper.

Bad Brake Caliper Symptom

The most common symptoms of a bad brake caliper are brake warning lights coming on, uneven brake pad wear, leaking brake fluid, vehicle pulling to one side during braking, clucking noises, soft spongy brake pedal or reduced braking ability.

1. Brake Warning Light Come On

Disc brake systems of modern vehicles with worn out calipers may display a brake warning light on the dashboard, indicating any failure of the vehicle’s brake system.

2. Clucking Noises

In the braking system of vehicles, often due to a bad brake caliper, you hear clucking noise while driving the vehicle on rough roads. This noise often seems to come from inside the wheel of the vehicle. However, there can be many other reasons for unusual wheel noise. For example, bad suspension, bad wheel bearings, a bad axle, or a bad CV joint.

3. Leaking Brake Fluid

brake caliper fluid leak

Often, brake caliper wear can result in brake fluid leaking from around the brake caliper assembly and if the piston of the brake caliper is more damaged, the fluid can be seen leaking on the inner side of the wheel when the driver presses the brake pedal.

4. Soft Spongy Brake Pedal

If the brake caliper in the vehicle’s braking system is damaged, you will experience a soft spongy brake pedal when you press the brake pedal, and the brake pedal sinks down when you hold the brake pedal down continuously. Because bad brake calipers are unable to stop the expansion of brake fluid, pressurized fluid leaks when the brake pedal is depressed.

5. Uneven Brake Pad Wear

Bad brake calipers often lead to uneven wear of the brake pads. because the pistons of bad brake calipers are unable to evenly press the brake pads, due to which the brake pads start wearing unevenly. However, these symptoms can also be caused by a bad disc brake rotor.

6. Vehicle Pulling To One Side During Braking

Often, when the brake caliper of a vehicle is damaged, the vehicle starts pulling to one side during braking. Because the braking system is on both sides of the vehicle, the piston of the brake clipper on one side gets stuck or the piston is unable to withstand the pressure of the fluid.

Due to this, when applying brakes at high speed, one side’s brake gets engaged and the other side’s brake system fails, causing the vehicle to start pulling to one side when the brake caliper fails during braking.

Brake Caliper Replacement Cost

Generally, the replacement cost of one unit of front wheel brake calipers in normal cars can range from $170 to $250, including the mechanic’s labor cost. Taxes and fees are not included in this estimated replacement cost.

  • Front wheel single unit calipers can cost between $100 and $150.
  • A mechanic’s labor costs can range between $70 and $100.

The replacement cost of a brake caliper depends more on the model of the vehicle, the location of the mechanic, and the caliper model. Because the prices of single piston calipers, dual piston calipers, and four piston calipers are different. If you have experience replacing your vehicle’s brake caliper and have the necessary tools available to do so, Then you can also save on the labor cost to be paid to the mechanic.


Q. Is it ok to drive with a bad brake caliper?

No, as it is never recommended to continue driving with a damaged brake caliper. Doing so can be extremely dangerous to your vehicle and to your and other road users’ safety. If you choose to continue driving your car, you may cause additional damage to the vehicle’s brake pads.

Q. How long do calipers last?

In typical vehicles, the recommended repair or replacement for brake calipers is every 40,000 to 60,000 miles. However, vehicle type and driving habits can affect the lifespan of a brake caliper. That’s why it’s important to regularly inspect your vehicle to make sure that the brake calipers are working properly.

Q. What causes caliper damage?

Often, worn brake pads and damaged rotors are the cause of vehicle brake caliper wear. Because damaged brake pads and rotors get hotter, the brake caliper is more likely to fail. Along with this, not taking care of the brake caliper regularly can also lead to its deterioration.

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