Friday, April 12, 2024

How Do Car Brakes Work

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How Do I Check My Brake Pads

How car brakes work

Checking your brake pads may be something youd want to do every now and again to ensure your vehicle is stopping as well as it should be. Thankfully, this can be done by ear sometimes as brake pads are designed to make an unpleasant squeaking sound when they come into contact with the disc. So, if you hear such a sound, then it may be best to check your brakes and get them serviced.

You can do this by jacking up your vehicle, removing each wheel and checking the pads. If any of the brake pads are less than an eighth of an inch thick, they should be changed immediately. They should also be changed if they have any dents, rust or have been warped. Read our full guide to checking brake pads here.

The best thing to do if you are concerned about your brakes is to take your car to a service centre to get them looked at by a specialist who can change them there and then if need be. Brake pads typically last for up to 60,000 miles of driving, though you may need them replacing sooner depending on how and where you drive. You should be able to schedule brake pad replacement into your annual service and many providers will also throw in a year or more warranty for peace of mind.

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How Stopping Happens

When youre moving, or when your car is moving, there is kinetic energy present. The heavier you are and the faster you are moving, the more kinetic energy you have. So obviously, cars have a fair amount of kinetic energy.

To stop movement, such as when a cat jumps in front of your vehicle, you must stop the kinetic energy. One way to do that is to use a parachute, which creates drag and reduces your speed. Thats how many drag racing cars work, for instance. But since youre probably just driving in a typical vehicle, you will use brakes instead.

Why Brakes Go Bad

As with any part of your car, the brakes will not last forever. They endure a lot of wear and tear, so eventually, good brakes can fall into disrepair. Replacing brake pads are a fairly simple repair, but its important to get any brake service done as soon as possible to avoid more costly repairs.

For starters, you should be aware of the signs and symptoms of brake failure, which may include:

  • A screeching sound when you apply the brakes
  • Reduced responsiveness for your brakes
  • Your car pulling to one side as you brake
  • Vibrations as you apply the brake pedal

The single best way to ensure healthy brakes is to have them inspected regularly, and to take them to be serviced at the first sign of trouble. Brake maintenance will help your vehicle maintain its all-important ability to stop. Thats good news for that stray cat as well as yourself!

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What Is A Brake Inspection

Thorough, comprehensive, extensive, and methodical are just a few characteristics that describe our brake inspections. When we say brake inspection, we not only mean it, but we demonstrate it on every automobile we service. Because in order to detect a problem, we need technicians that not only can spot potential problems, but also have the know-how and precision to regain brake awesomeness. When were finished, youll have total confidence knowing your ride has received a brake inspection thats hard to match.

Brake Inspection includes checking your brake:

  • pads

Who Invented Hydraulic Brakes

How Do Car Brakes Work?

Malcolm Loughead of Detroit, Michigan invented “fluid-operated” brakes in 1919and here’s one of his improved designs from the mid-1920s. It uses the momentum of the car to provide the force that pushes the hydraulic piston into the cylinder, giving a kind of power-assisted braking. Loughead and his brother Allan were airplane pioneers and the founders of the Lockheed Corporation .

Artwork: When your foot presses the brake pedal , it pushes on a lever that applies a friction belt to a drum surrounding the vehicle’s drive shaft . As the belt locks on, the force from the moving drive shaft tugs it to the right, pushing a lever also to the right. This forces a piston into a hydraulic cylinder , pushing hydraulicfluid down a pipe that applies the brake to the back wheel .Artwork from US Patent 1,732,309: Fluid-operated Brake by Malcolm Loughead, courtesy of US Patent and Trademark Office.

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How Brake Discs Are Made

These metal discs bolt between the wheel and hub and provides the friction surface for the pads to act against. Brakes can either be solid or vented for aiding cooling.

Vented discs are commonly used on the front of cars where the braking forces are higher and are subject to greater temperatures.

Brake Pads Fitted in pairs to each disc, the pads are made of a very hard wearing compound that provides excellent heat resistant properties and the ability to provide a high level of friction against the brake disc.

Brake Drums Not as common on modern cars, but still fitted to the rear of some smaller, and lower powered cars. The brake pads or ‘shoes’ are housed within the drum, and pressing the brakes forces the shoes outwards onto the inner edge of the drum which slows the car.

Brake Caliper Calipers come in many shapes and sizes and employ one or more hydraulically actuated pistons which force the pads into contact with the disc when the brake pedal is pushed. The more pistons a caliper has the more evenly distributed the braking force is across the pad, and the larger the pad surface can be. The larger the pad the greater the friction acting on the disc therefore the better the stopping power.

We Explain How Car Brakes Work And How To Check Your Brake Pads

The brakes on a car are one of its most vital features to keep us safe. Its hard to underestimate their value, because they ensure that a car can be controlled safely and brought to a stop when required. Otherwise, a tonne or more of car would become an incredibly dangerous hazard. But how do car brakes work?

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What About Brake Fluid Leaks

Featured Image Credit:IgorShubin / Pixabay

Brake fluid is a hydraulic fluid that transfers force, creating pressure that ultimately enhances braking force.If there is a brake fluid leak and it is fairly slow, there will not be sufficient fluid remaining to fill up the brake cylinder. As a result, the brakes will not work as designed. If the leak is significant, the initial time the brakes are pressed will cause the fluid to leak, spurring total brake failure. However, todayâs vehicles have a master cylinder engineered to handle such issues.

How Does The Braking System Work

BRAKES: How They Work | Science Garage

Hydraulic brake systems convert mechanical energy into heat energy by transforming and amplifying the force exerted on the brake pedal. The brake pedal acts like a lever. Along with the brake booster, it greatly multiplies the force applied on the brake fluid in the master cylinder.

The master cylinder also increases brake fluid pressure, then sends pressurized brake fluid, via brake lines and hoses, to the brake calipers and wheel cylinders. The pressurized fluid acts on the caliper piston, squeezing the disc brake pads inward, clamping the pads against the brake rotors.

On drum brakes the wheel cylinders slide outward, forcing the brake shoes against the drum using a wedging, jamming action similar to how a bicycle coaster brake works. The energy of the pads clamping against the rotors and brake shoes pushing against drums generates friction and heat. This heat-friction, along with friction generated between the tire and road surface, slows rotor and axle rotation and ultimately brings the car to a stop.

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How Car Brakes Work

When you apply your vehicle’s brakes to stop at a traffic light or avoid a road hazard, you count on them to keep you, your passengers, and your vehicle safe. But you likely dont give much thought to how they work.

There are two types of car brakes: disc brakes and drum brakes. Both disc brakes and drum brakes work by using friction and resistance to convert kinetic energy into heat energy. A hydraulic system creates that friction. Fluid moves through brake lines in the hydraulic system to create pressure, pushing disc brake pads against the brake rotors and stopping the car. Drum brakes work the same way, with brake shoes pressing against the drum. All cars come equipped with four brakes: two rear brakes and two front brakes. In most cars, front brakes are primarily responsible for halting your vehicle and provide 60% to 90% of the vehicle’s stopping power.

When Should I Replace My Brakes

Brakes. What are they really, what do they do, how often do I need to replace them, and how much should I be paying for them? These are all questions we find ourselves asking every 50,000 miles or so .

Today were unpacking everything you need to know about brakes and when to replace them to keep you safe and informed on the road. First up, the basics:

Note: For the purposes of this blog, were going to be using a car as our example

What are brakes? Whats the difference between pads and rotors? Calipers?

Brake systems are complex and go beyond just the two parts youve probably heard most about: brake pads and brake rotors. Here is a brief explanation of each part:

  • Brake pads: Brake pads press on the rotors to slow the car. Quality matters with brake pads they can last a few years, but harder pads will last longer than soft pads. Eventually, the padding wears down to the metal
  • Brake pistons: Pistons create friction on the rotors by pressing against the brake pads theyre activated by the brake fluid that is pushed through the hydraulic system when you press down on the brakes.
  • Brake rotors/discs: This is one of the main parts of your brake system. When your brake pads press against the rotoros, this is what makes your car slow to a stop. These pieces can last up to about 70,000 miles and their life can be extended with resurfacing.

How often do I need to replace my brakes?

The factors that can affect how often you need to replace your brakes are:

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The Science Of Stopping

If you’re moving, you have energykineticenergy to be precise.Kinetic energy is simply the energy an object possesses because it hasboth mass and velocity .The more mass you have and the faster you’regoing, the more kinetic energy you have.

That’s all well and good, but what if you suddenly need to stop? Tochange from moving quickly to not moving at all, you have to get rid ofyour kinetic energy.

If you’re jumping from an airplane, the bestway to lose energy is with a parachute. This giant sack of fabric dragsbehind you, slowing you down, reducing your velocity, and thereforehelping to get rid of your kinetic energy. That means you can landsafely. Drag-racing cars and land speed record cars also use parachutesto stop but, in practice, most vehicles simply use brakes.

Chart: The faster you go, the more kinetic energy you have and the harder your brakeswill have to work to stop you.

The Role Of Distance And Diameter In Timely Braking

How disc brakes work

The distance between the brake pedal and the pivot component of the braking system are of particular importance. If the distance between these two is four times that between the cylinder and pivot, the force applied to the pedal must increase by a multiple of four prior to its transmission to the cylinder. The brake cylinder diameter is also likely to be upwards of three times the pedal cylinderâs diameter. This diameter difference multiplies the force all the more.

Letâs assume the force is multiplied by nine. In total, this system boosts the force of the driverâs foot by a 36 factor. Therefore, if 12 pounds of force area applied to the pedal, 432 pounds are generated as the brake pads are squeezed by the wheels.

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What Are Disc Brakes

Just like that of a pedal bike, a modern cars braking system is made up of three main components callipers, pads and discs. The caliper is the part you can see first and foremost and is the part of the system that creates friction and acts as a clamp around the disc. These calipers are often painted in bright colours on sportier cars to emphasise the theme of performance.

Attached to either side of a caliper are the brake pads the materials that make contact with the discs under braking. The discs themselves are fitted to the inside of your cars wheels. As you apply pressure to the brake pedal, brake fluid pushes a piston against the caliper, causing it to squeeze the pads against the disc. This in turn slows the turning wheel and therefore, the car down.

Brake pads are the part of the whole system that usually need replacing first since they are made of a softer material than the discs, and therefore wear much quicker as they are essentially eroded away by the metal discs.

Heres How Hydraulics Works

Hydraulics uses pressurized liquid to create power. This works because liquids cannot be compressed. So if you try to compress a liquid that is inside a sealed container, it will push out on all sides of the container, looking for a place to go.

Think of squeezing a plastic water bottle. If the cap is removed the water will shoot out of the top. If the cap is tightly secured , you will only be able to squeeze the bottle so far. Since water doesnt compress, hydraulics stops you from collapsing the bottle. If you leave the cap loose, and squeeze the bottle real hard, hydraulic pressure will blow the cap right off the bottle.

So when you step on your brake pedal, you are pressurizing the entire brake system, applying the brakes.

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So What Happens When You Press The Brake Pedal

As you press the brake pedal the force generated by your leg is amplified via mechanical leverage within the pedal assembly, then amplified further by the action of the brake servo.

The mechanical force of pressing the pedal is converted into a hydraulic force by the master cylinder. This forces hydraulic fluid around the braking system via a network of brake lines.

The fluid forces small pistons within the brake calipers to push the brake pads onto the brake discs, and it’s this clamping force which slows the car down.

How Do Brakes Work

How car brakes work | ACDelco

Just as your ankle bone is connected to your foot bone, your brake system relies on each connected brake part to function successfullyand safely.

Heres a quick lesson: By pressing down on the brake pedal, you activate the cylinder that delivers brake fluid to the calipers that then engage your brake pads. Your brake pads then apply pressure to the rotors, creating the friction needed to stop your car. You see, its all connected.

All your brake parts work together to perform one important and crucial function: safe and precise stopping power.

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What Kind Of Brakes Does My Car Have

Your vehicle has disc brakes or drum brakes, or a combination of the two. Most modern cars come with disc brakes. Typically most front brakes on vehicles sold in the U.S. are disc brakes, but you may find the rear brakes are drum brakes.

Why are disc brakes better? They typically last longer than drum brakes, do abetter job of dissipating heat, and hold up better in wet weather.

These days, youll find that most newer vehicles come with an anti-lock braking system. This system helps prevent the brakes from locking up. Brakes locking up can lead to skidding and a loss of steering control.

Putting It All Together

So lets put all the parts of the braking system together.

You step on the brake pedal. That activates the brake booster, which amplifies the force from the brake pedal. That force is transferred to the master cylinder. A piston in the master cylinder pushes out brake fluid through brake lines to each wheel.

If a wheel has a drum brake, the brake fluid will engage a piston in the wheel cylinder, which will activate another piston, which will push out the brake pads against the brake drum. The car slows down or stops. When you release the brake pedal, the brake fluid will flow back into the master cylinder and the brakes will release.

If the wheel has a disc brake, the brake fluid will activate a piston that will cause calipers that have brake pads to squeeze against a disc, or rotor, attached to the wheel, slowing the car down. When you release the brake pedal, the brake fluid flows back into the master cylinder, causing the calipers on the disc brake to open up again.

That, in a nutshell, is how your cars brakes work.

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Work On Braking Systems As An Automotive Technician

Pursuing a career as an automotive technician can help give you the opportunity to learn all about brake systems. The skilled trades are growing its expected that there will be a combined total of more than 720,000 automotive service technicians and mechanics nationally by 2029.47Training as an automotive technician at Universal Technical Institute can give you the hands-on experience employers are looking for when hiring.1

Courses taught over UTIs 51-week Automotive Technology program cover a range of topics for the role, including a section about vehicle braking systems. You can graduate in less than a year ready for an entry-level position in the industry!7

Interested in finding out more? Request more information, or call 800-834-7308 today!

Classes start soon.Hands-on training.No Pressure to commit.

What are anti-lock braking systems , and how do they work? Learn all about ABS and why its such an important safety feature in cars today.

Take 60 seconds and find out how you can get trained.

  • How Do Car Braking Systems Work?

1) UTI is an educational institution and cannot guarantee employment or salary.

2) For program outcome information and other disclosures, visit

7) Some programs may require longer than one year to complete.

10) Financial aid, scholarships and grants are available to those who qualify. Awards vary due to specific conditions, criteria and state.

16) Not all programs are accredited by the ASE Education Foundation.

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