What Brake Parts Are Called: Key Components You’ll Hear About

Common brake parts include rotors (discs), pads, calipers, master cylinder, brake lines and hoses, brake fluid, booster, ABS module and wheel-speed sensors, as well as drums, shoes, and wheel cylinders on vehicles with drum brakes. These components work together to convert pedal pressure into friction and controlled stopping power, whether in everyday driving or performance scenarios.

Core Disc Brake Components

Disc brakes are the most widely used setup on modern vehicles, known for consistent stopping power and heat management. Below are the primary parts you’ll encounter on a typical disc-brake axle.

• Brake rotor (disc): The spinning iron or composite disc clamped by pads to create friction.
• Brake pads: Friction blocks that press against the rotor; available in ceramic, semi-metallic, and low-metal formulations.
• Caliper: The hydraulic clamp that squeezes the pads; can be floating (single or dual piston) or fixed (multi-piston).
• Caliper bracket (carrier): Mounts the caliper and holds pad hardware in place.
• Guide pins/sliders: Allow a floating caliper to move freely for even pad wear.
• Dust boots and piston seals: Keep contaminants out and maintain hydraulic sealing inside the caliper.
• Pad shims/anti-squeal shims: Reduce vibration and noise between pads and caliper/pistons.
• Backing plate/dust shield: Protects the rotor and components from road debris and directs airflow.

Together, these parts deliver the friction needed to slow the wheels, with the caliper and pads applying controlled force to the rotor to convert kinetic energy into heat.

Hydraulic and Mechanical Control Components

Hydraulic pressure translates your foot’s effort into clamping force at the wheels. These components build, route, and regulate that pressure across the braking system.

• Master cylinder: Pressurizes brake fluid when the pedal is pressed.
• Brake fluid and reservoir: DOT 3, DOT 4, and DOT 5.1 are glycol-based; DOT 5 is silicone-based and not compatible with glycol fluids.
• Brake booster: Vacuum or hydroboost unit that amplifies pedal force for lighter effort.
• Brake pedal assembly: Mechanical linkage that actuates the master cylinder.
• Brake lines (hard lines) and flexible hoses: Steel lines and rubber or braided hoses that carry pressurized fluid to each wheel.
• Proportioning/combination valve: Balances front-rear pressure and may integrate metering and warning functions.
• Residual pressure valve (where fitted): Maintains slight line pressure in certain systems.
• Load-sensing proportioning valve: Adjusts rear brake force based on vehicle load (common on trucks).
• Banjo bolts and copper crush washers: Seal hose-to-caliper connections.

This network ensures pressure is delivered precisely to the front and rear brakes, maintaining stability and pedal feel across different driving conditions.

Drum Brake Components

Though many vehicles use rear disc brakes, drum brakes remain common on budget models and some trucks. They house multiple spring-loaded parts inside a drum that rotates with the wheel.

• Brake drum: The cylindrical friction surface inside which the shoes expand.
• Brake shoes (primary/secondary): Curved friction linings that press outward against the drum.
• Wheel cylinder: Hydraulically pushes the shoes outward.
• Return springs: Pull shoes back after braking.
• Hold-down springs and pins: Retain shoes against the backing plate.
• Adjuster (star wheel) and lever: Maintains correct shoe-to-drum clearance.
• Self-adjuster cable/guide: Links shoe movement to the adjuster mechanism.
• Backing plate: Mounting surface for all drum hardware.
• Parking brake lever/actuator: Integrates the handbrake function within the drum assembly.

While more complex to service than discs, drum assemblies provide robust parking brake performance and can be cost-effective for rear applications.

Electronic Braking and Stability Components

Modern vehicles layer electronics atop hydraulics to improve safety and consistency, especially in low-traction conditions and emergency maneuvers.

• ABS module and pump: Modulates hydraulic pressure to prevent wheel lock-up.
• Hydraulic control unit (HCU) with solenoids: Routes pressure to individual wheels under ABS/ESC control.
• Wheel speed sensors (ABS sensors): Monitor each wheel’s rotation; often read via a tone ring/reluctor.
• Electronic stability control (ESC) and traction control: Use ABS hardware plus yaw and steering sensors to correct skids.
• Brake pad wear sensors: Warn when pads approach minimum thickness.
• Electronic parking brake (EPB) actuators: Motor-driven calipers or cable modules that apply the parking brake.
• Brake light switch: Signals pedal application for lamps and driver-assist systems.
• Brake-by-wire/iBooster units (common on hybrids/EVs): Electric assist that blends hydraulic and regenerative braking.
• Regenerative braking controller (hybrids/EVs): Recovers energy while coordinating friction braking as needed.

These components enhance stopping control, integrate driver aids, and, in electrified vehicles, recover energy to improve efficiency.

Service Hardware and Wear Items

A number of small parts and consumables ensure the system functions quietly, safely, and reliably after installation or during maintenance.

• Pad abutment clips and anti-rattle springs: Help pads move freely and reduce noise.
• Caliper bolts and guide pin boots: Secure and protect the sliding mechanism.
• Bleeder screws: Allow removal of air during brake bleeding.
• Crush washers and seals: Provide leak-free hydraulic connections.
• Wheel hub/bearing and wheel studs: Support the rotor and wheel; critical for runout and vibration control.
• Rotor set screws (on some makes): Temporarily retain rotors during service.
• High-temp brake grease and threadlocker: Used where specified to prevent noise and fastener loosening.
• Brake hardware kits: Bundles of clips, springs, and pins for a complete refresh.

Replacing hardware alongside pads and rotors helps prevent uneven wear, noise, and pedal issues, extending the life of the repair.

Common Upgrades and Variants

Drivers seeking better performance, consistency under heat, or reduced unsprung mass often select upgraded brake components tailored to their needs.

• Vented, slotted, or drilled rotors: Improve cooling and gas/dust evacuation; vented is most common for heat control.
• Two-piece rotors and carbon-ceramic rotors: Reduce weight and improve heat tolerance in high-performance applications.
• Performance pad compounds: Semi-metallic for high bite/heat, ceramic for low dust/noise, track pads for elevated temperatures.
• Stainless braided brake lines: Reduce line expansion for firmer pedal feel.
• Multi-piston fixed calipers and big brake kits: Increase clamping area and thermal capacity.
• Brake cooling ducts and shields: Direct airflow to manage temperatures under sustained braking.

While upgrades can enhance feel and fade resistance, correct sizing and quality installation are essential to maintain balance and safety.

How These Parts Work Together

Pressing the pedal moves a pushrod into the booster and master cylinder, generating hydraulic pressure in brake lines. That pressure travels to calipers or wheel cylinders, forcing pads against rotors or shoes against drums to create friction. Electronic modules monitor wheel speeds and vehicle motion, adjusting pressure to keep the car stable and prevent lockup. In hybrids and EVs, brake-by-wire systems blend regenerative deceleration with friction braking for seamless stopping.

Maintenance Tips and Signs of Trouble

Routine inspections and timely replacement of wear items keep braking performance predictable and safe. Be alert for the following symptoms and address them promptly.

• Squealing or grinding: May indicate worn pads or glazed surfaces.
• Pedal pulsation or steering wheel shake: Often due to rotor thickness variation or runout.
• Spongy or sinking pedal: Air in the system or internal master cylinder issues.
• Vehicle pulls during braking: Sticking caliper, uneven pad wear, or hydraulic imbalance.
• ABS or brake warning lights: Sensor faults, low fluid, or HCU/module problems.
• Fluid leaks or wet calipers/lines: Compromised hoses, seals, or connections.
• Cracked hoses or bulging lines: Replace immediately to prevent failure.

Addressing these signs early—along with using the correct fluid and torque specs—helps ensure consistent braking and reduces long-term costs.

Summary

Brake systems combine friction parts (rotors/discs, pads, calipers or drums/shoes), hydraulic controls (master cylinder, booster, lines, valves), electronics (ABS, wheel-speed sensors, HCU), and service hardware to convert pedal input into safe, controlled deceleration. Knowing the names and roles of these components helps you discuss repairs confidently, evaluate upgrades, and spot issues before they escalate.

How to know if a brake caliper is bad?

You can tell a brake caliper is bad by looking for signs like the vehicle pulling to one side, a soft or spongy brake pedal, unevenly worn brake pads, a burning smell or excessive heat from the wheels, fluid leaks under the car, or abnormal noises like grinding or squealing during braking. A dragging sensation or vibration in the brake pedal are also common indicators of a failing caliper. 
Signs to look for while driving:

• Vehicle pulling: If your car pulls to one side while braking, it can indicate a seized or sticky caliper applying uneven pressure. 
• Reduced braking power: A softer or “spongy” brake pedal that requires more pressure to stop is a sign of reduced hydraulic force, possibly from leaks. 
• Burning smell or heat: A burning smell or excessive heat coming from a wheel, especially after driving, suggests the brake is dragging and overheating. 
• Abnormal noises: Grinding, squealing, or clunking noises during braking can signal worn pads, a lack of lubrication, or other caliper issues. 
• Vibrations: A pulsing or vibrating sensation in the brake pedal or steering wheel when braking often means uneven pad wear or a malfunctioning component. 

Signs to look for when inspecting the vehicle:

• Fluid leaks: Opens in new tabBrake fluid leaks, indicated by puddles of fluid under the car or low fluid levels in the reservoir, can stem from damaged caliper seals. 
• Uneven brake pad wear: Opens in new tabVisually inspect the brake pads; if one side is significantly more worn than the other, a sticking caliper may be the cause. 
• Dragging brakes: Opens in new tabAfter driving, carefully touch the wheels to check for excessive heat, which can mean a caliper is constantly engaged. 
• Sticking wheel: Opens in new tabWith the car on jack stands, try to spin the wheel by hand. Significant resistance or a wheel that stops spinning quickly could be a stuck caliper. 

What to do if you suspect a bad caliper: 

• Get an immediate inspection: If you notice any of these symptoms, have your brakes inspected by a mechanic to prevent potential accidents and more costly repairs.

What are the 4 major parts of a disc brake system?

When it comes to disc braking systems, there are four parts you need to know: The pads, rotors, calipers, and hardware. The system is responsible for… well, braking. However, as with any other component within your vehicle, each aspect of the braking system serves a different purpose.

What is the part called that holds the brake pads?

The part that holds the brake pads in a disc brake system is the brake caliper. The brake pads sit inside the caliper, and when you apply the brakes, the caliper clamps the pads against the spinning brake rotor to create friction and stop the vehicle.
 
How the caliper holds the pads:

• Caliper Body: The caliper is a clamp-like metal housing that surrounds the rotor. 
• Pistons: Hydraulic pistons inside the caliper move when you press the brake pedal, pushing the brake pads against the rotor. 
• Caliper Bracket: Some sources also mention the caliper bracket as the part of the assembly where the brake pads are installed. 
• Hardware: Anti-rattle clips or abutment clips also help to hold the brake pads in place and reduce noise. 

What are the names of brake parts?

Here are the main parts of the brake system that you should know:

• -Brake Pad. This is a block-like structure that presses itself against the brake rotor to stop the wheels from rotating.
• -Brake Rotor.
• -Brake Caliper.
• -Brake Shoes.
• -Brake drum.
• -Backing Plate.
• -Return Springs.
• -Wheel cylinder.