How do brakes work on a car?

13 minute read Published on Aug 9, 2024 by BrokerLink Communications

A mechanic's hand checking a car's brake discs wear with calipers.

Braking might seem straightforward: you press the brake pedal, and your car slows down and stops. However, the braking system is actually quite complex, with many parts working together to make sure everything functions correctly. Modern cars have advanced brake systems that combine various components to ensure your safety and the safety of others on the road. Let’s explore how brakes work to stop your car when needed.

What are brakes?

First, let’s talk about the two types of brakes: disc and drum brakes.

  • Disc brake system: A disc brake system consists of brake callipers, brake pads, and a brake disc (rotor). When you press the brake pedal, the callipers press the brake pads against the disc. This creates friction that slows down the rotor, axle, and wheels, bringing the car to a stop.
  • Drum brake system: A drum brake system consists of hydraulic wheel cylinders, brake shoes, and a brake drum. When you press the brake pedal, the hydraulic wheel cylinder forces the brake shoes against the inner surface of the drum. The brake pads clamp against the rotors, and the brake shoes push against the drums to generate friction. The friction slows the rotor, axle, and wheels to bring the car to a stop.

Most modern cars have brakes on all four wheels. When you brake, the car’s weight moves forward, so the front brakes do most of the work. Some cars have disc brakes on all four wheels, while others have disc brakes in the front and drum brakes in the back.

To tell if your car has disc or drum brakes, look through the holes in your front wheels. If you see a shiny, smooth surface, it’s a disc rotor. If you see a rusty, rough surface, it’s a brake drum. You can also check the back of the wheels: drum brakes have a metal tube, while disc brakes have a rubber hose connected to the brake calliper.

Understanding brake systems

Whether it’s disc brakes or older drum brakes, both work by creating friction to slow down the wheels. This friction makes it much harder for the wheels to keep turning, which significantly reduces the vehicle’s speed. Here’s what happens when you engage your brakes:

Each wheel on your vehicle has its own brake with a hydraulic device. When you press the brake pedal, all four brakes respond.

Pressing the pedal moves a lever connected to a piston. This piston, powered by your foot, pushes brake fluid from the master cylinder into the brake lines. These lines lead to either the brake callipers (in a disc brake system) or the wheel cylinders (in a drum brake system).

The brake fluid, under pressure from the master cylinder, increases the force from your foot. This force makes each brake calliper press the brake pads against a rotor, creating friction to slow down the car. In a drum brake system, each wheel has a cylinder that pushes a pair of shoes outward against a drum to create friction.

How long do brakes last?

The lifespan of disc brakes and drum brakes depends on many factors. A good rule of thumb is to check your brakes every six months. Keep reading to learn more:

Drum brakes

Drum brake housings typically last between 240,000 and 320,000 kilometres, and brake shoes, depending on usage, last between 56,000 and 65,000 kilometres.

Disc brakes

The lifespan of disc brake pads varies depending on how much pressure is applied during braking and how often they’re used. Most vehicles get between 50,000 and 150,000 kilometres for brake pads and rotors.

A guide to brake system components

The braking system has many parts working together to make sure your car stops when you press the pedal, including the brake pedal, booster, and shoe. Let’s break down each working part for you:

Brake pedal

The brake pedal directly controls the braking system. You press the brakes with your foot to slow or stop your vehicle. It’s the pedal under your steering wheel and beside your gas pedal. The brake pedal directly controls the master cylinder and is connected to the brake booster.

Brake booster

The brake booster connects to the master cylinder to amplify the force applied to the pedal and transferred to the cylinder. It enhances the performance of your car's brakes and makes it easier to stop or slow down the vehicle without using much force.

Master cylinder

The master cylinder delivers brake fluid to the front and rear wheels through metal tubes and brake hoses. It converts the force on the pedal and sends pressurized brake fluid into the braking system. Increased brake fluid pressure activates the wheel cylinders and brake callipers. Master brake cylinders are part of disc brakes and drum brakes.

Brake fluid

Brake fluid is a key part of the braking system. It transfers the force from your brake pedal to the brake parts that stop the car. It flows through the brake lines and is essential for the system to work properly.

Brake callipers

Brake callipers are an essential component of cars with disc braking systems. It supports the brake pads on both sides of the rotor and the calliper bracket. The callipers squeeze the brake pads against the brake discs or rotors. The brake fluid forces the calliper piston towards the rotors, causing friction and slowing the car.

Brake pads

Brake pads are crucial parts of the braking system. They press against the rotors to create friction and slow down your vehicle. They are located inside the brake callipers and work every time you press the brake pedal.

Brake rotors

Brake rotors are another crucial part of your car’s braking system. They are discs that the brake pads clamp onto to create friction and slow down your vehicle. The rotors are attached to the wheels, so when you press the brake pedal, the pads squeeze the rotors to stop the car.

Brake shoes

The brake shoe carries the brake lining in the drum brakes. It pushes outwards against the inside of the drum when you press the brakes. Although they have become less common in modern cars, some vehicles have brake shoes on the rear wheels.

Types of braking systems

There are many types of braking systems in cars today. It’s important to understand your car braking system so you can troubleshoot or service it correctly:

Hydraulic braking system

The hydraulic system uses brake fluid, cylinders, and friction and is one of modern vehicles’ most important braking systems. The fluid-filled master cylinders connect via brake pipes to transmit hydraulic pressure to slave cylinders. The direct connection between the actuator and the brake disk or drum has a low chance of brake failure.

Anti-lock braking systems (ABS)

The Anti-lock Braking System (ABS) is essential for modern vehicles. It prevents the wheels from locking up during hard braking, helping you maintain control. ABS uses sensors and electronic control to monitor wheel speed and rapidly pulses the brakes if it detects skidding. This ensures better traction and stability when stopping quickly on low-friction surfaces like wet, icy, or snowy roads.

Electromagnetic braking system

Electromagnetic braking systems are popular in modern and hybrid vehicles. It uses electromagnetism for frictionless braking, which can increase the lifespan of the brakes. When you press the brake pad, the magnetic flux attracts the rotator to the face of the brake and squeezes the inner and outer discs together.

Regenerative braking system

Regenerative braking systems are common in electric and hybrid cars. They use the car’s electric motor to help slow it down, converting some of the energy into electricity to recharge the battery. When you press the brake pedal, the system switches the motor to work in reverse, helping to slow the car and recover energy at the same time.

Mechanical braking system

Mechanical braking systems power the hand brake and parking brake, previously called the emergency brake. They stop the vehicle through cylindrical rods, springs, fulcrums, etc. Hand brakes can be used by pressing a pedal, pulling a lever on the floor, or using a handle inside the car. When the hand or parking brake is on, a warning light on the dashboard turns on to prevent damage to the brake parts if you try to drive with the hand brake still engaged. A hand brake or parking brake is more common in old cars than newer ones.

What causes brakes to wear down?

Brakes wear down over time due to regular use and several other factors. When you press the brake pedal, the brake pads press against the rotors or drums, creating friction to slow down the car. This friction causes both the pads and rotors or drums to wear down gradually. Here are the main reasons brakes wear out:

Driving habits

Your driving style greatly affects brake wear. Aggressive driving, with frequent hard braking, will wear down your brakes faster than smooth, gradual braking. Similarly, riding the brakes and keeping your foot on the brake pedal constantly can cause excessive wear.

Environment

The conditions in which you drive also impact brake wear. City driving with lots of stops and starts wears brakes more quickly than highway driving. Additionally, driving in hilly or mountainous areas requires more braking, leading to faster wear. Dusty or sandy environments can also accelerate brake wear, as particles can get into the brake system and cause additional friction.

Brake quality

The materials used in your brake pads and rotors also affect their lifespan. High-quality brake components tend to last longer and perform better under extreme conditions compared to cheaper, lower-quality alternatives.

Heat

Braking generates a lot of heat due to the friction between the pads and rotors or shoes and drums. Repeated heavy braking, such as in stop-and-go traffic or during downhill driving, can cause the brake components to heat up significantly. This heat can cause the brake pads and rotors to wear faster. In some cases, the heat can even cause the brake fluid to boil, reducing braking efficiency.

Weight

Heavier vehicles put more strain on brakes. Carrying extra cargo or towing can also accelerate brake wear.

Regular maintenance, such as checking brake pads and rotors and replacing them when necessary, helps ensure your brakes work effectively and last longer.

Signs your brakes are wearing down

There are several signs that can indicate problems with your car’s braking system. It’s important to get your car checked right away if you notice any of these issues:

You have to press the brake pedal hard to stop

If you have to press the brake pedal harder or if it feels soft or spongy, it could mean parts of the braking system are worn out.

You can hear loud noises

Strange or loud noises, such as screeching, grinding, or squealing when braking, can indicate that the brake pads or shoes are worn down.

Your steering wheel is vibrating

If you feel vibrations when you apply the brakes, it could mean the rotors are uneven or warped.

Your car pulling to one side

If your car pulls to one side when you brake, it could be because the brake pads are wearing unevenly.

Your brake light is on

If the brake warning light on your dashboard comes on, you should get your car checked by a mechanic right away.

What to do if your brakes stop working

If you ever find yourself in a situation where your brakes fail to engage, here’s what you should do:

Stay calm

Try not to panic. Staying calm helps you think clearly and react quickly, which is crucial for your safety and others’ safety.

Try them again

Make sure nothing is stuck under the brake pedal. For regular brakes, pump the brake pedal quickly and firmly. For antilock brakes, press the pedal down and hold it. If it goes to the floor, pump it a few times and then hold it down again.

Turn on your hazard lights and shift to a lower gear

If the brakes still don’t work, turn on your hazard lights to warn other drivers that something is wrong. Then, take your foot off the accelerator and shift to a lower gear. In a manual transmission, downshift through the gears. For automatic transmissions, removing your foot from the accelerator should slow you down, or you may need to use manual mode or paddle shifters.

Use the hand brake

Once the car slows down a bit, gently apply the hand or parking brake. It works separately from the hydraulic brake system and can help stop the car. If the car skids, release the hand brake and try again slowly.

Find a way to create friction

If you’re still not stopping, carefully rub your car against a guardrail, curb, or barrier. This will create friction and help slow you down, though it might damage your car. Try to carefully get into the right lane and stay aware of other vehicles.

Steer your car off the road

If possible, steer away from traffic. Find an open area like the shoulder, a grassy area, or bushes to slow your car to a stop. Do not turn off your car until it has fully stopped. Turning off the ignition can disable power steering, making it very hard to steer. Signal or call for help once you have stopped.

How does car insurance protect me if my failed brakes cause an accident?

After reporting the car accident, it’s time to minimize damages and, if possible, ensure that your vehicle is not blocking traffic or in a position where further damage may occur. Then, make arrangements to get your brakes fixed as soon as possible.

Aside from potential injuries, there are also costly financial repercussions if you can’t stop your car in time. Now, your car insurance comes into play. A robust car insurance policy protects you against third-party claims, accidents, and damages. Here are types of auto insurance that can help if your brakes ever fail:

Collision car coverage

Collision car coverage is optional and comes in handy if your brakes fail or someone else causes a collision. It covers repairs or replacements required resulting from the collision. Failed brakes often result in these accidents, so adding collision coverage to your insurance policy is a good idea.

Accident forgiveness

Accident forgiveness insurance protects your driving record in the event of an at-fault accident claim. If you become responsible for a collision or accident because your car brakes fail, accident forgiveness helps prevent your insurance premium from increasing because of the incident. You may still have to pay a deductible for repairs or damages to your vehicle.

Liability car insurance

Liability car insurance or third-party liability car insurance is mandatory as part of your auto insurance policy. It covers legal, medical, and settlement fees for at-fault incidents where you injure someone or damage their property. Your insurance provider can seek restitution for you in these cases even if you don’t get sued.

Uninsured automobile insurance

Uninsured automobile insurance is mandatory and protects you if you ever get into an accident with someone underinsured, uninsured, or unidentified. It may compensate you for any injuries sustained and damages to the vehicle.

Comprehensive car coverage

Many drivers like to have comprehensive car coverage because it covers damages from non-collision incidents. Non-collision incidents include falling objects, damages while the car is parked, theft, vandalism, and damages from fires or natural disasters. There’s peace of mind knowing you have comprehensive protection against incidents you don’t really have control over. Comprehensive coverage is mandatory in some parts of Canada.

How can I save on auto insurance?

Failed car brakes often result in collisions, injuries, and other accidents. Whenever you have an accident on the road, there’s always a chance your insurance premium could increase. We want to help you save money, so here are some tips to save on vehicle insurance:

Drive safely

You should always drive safely, and it’s one of the easiest ways to lower insurance premiums. Avoid common car accidents by paying attention to the road, taking precautions in poor weather conditions, and avoiding speeding or impaired driving. Plus, insurers often reward a clean driving history with a safe driving discount.

Bundle insurance policies

Most people like to bundle car insurance policies with homeowners insurance policies to save money. Purchasing multiple auto insurance policies from the same provider usually gives you a discount on each vehicle you add to your policy.

Increase your deductible

Your deductible is the amount you must pay out of pocket before your insurance company covers your claim. A common deductible is $500. If you can afford to have a higher deductible, you may pay less for your insurance each month because the insurance company can pay less for your claim after a car accident. Just be sure you can afford the higher deductible.

Ensure your vehicle is safe to drive

Take your car for routine maintenance and ensure it has safety features, such as blind spot detection, automatic emergency brakes, forward collision warning, lane departure warning, 360-degree camera, etc. When your car is safe for the road, you reduce the chances of brake failure and accidents, and insurers often reward safe cars with a discount.

Get auto insurance with BrokerLink today

Car insurance can be pricey depending on many factors, like where you live and your driving history. BrokerLink makes it easy and saves you money by comparing quotes and policies from top providers across Canada. Our experts advocate for you through the entire insurance process, from purchasing a policy to filing a claim.

You can reach us by phone, email, or in person at any one of our locations throughout Canada. No matter how you choose to get in touch, a BrokerLink insurance advisor will be happy to assist you. We also encourage you to take advantage of our free online quote tool that can provide you with a competitive quote in minutes.

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