How Car Brakes Work

We all rely on our car brakes for stopping or slowing down our car, especially during emergencies. But, do you actually know how brake systems do this? Here is the information that you need to understand the inner workings of this important safety net, as well as the most common symptoms of brake problems so you can know if you should have it checked by a mechanic.

Skip to:Disc Brakes|Drum Brakes|How to Know if You Need Brake Repair

Types of Car Brakes
In general, a car’s brake system is made up of disc brakes both for the front and rear wheels or disc brakes for the front wheels and drum brakes for the rear wheels. These are all connected via hoses and tubes from the master cylinder to the brake on every wheel. The brake system is also connected with other systems including the anti-lock system, power brake booster and parking brakes.

Once you push the brake pedal, you are pushing against the master cylinder’s plunger that in turn forces the brake fluid—via a series of hoses and tubes—to the car brakes at every wheel. It is vital to note that the brake fluid used for this process has to be pure liquid with no air bubbles.

This is due to the fact that air is compressible, which can cause the brake pedal to be “spongy,” resulting in decreased braking efficiency. In case air bubbles manage to pass through, your brake system should be “bled” to eliminate it. This process will be handled through the “bleeder screws” on every caliper and wheel cylinder.

Disc Brakes
Arguably, disc brakes are the finest and most widely used car brakes. Disc brakes are preferred over other brake systems because they are self-cleaning, more durable, self-adjusting, and known to withstand water, stopping, pulling, and grabbing. In fact, because of their superior characteristics, they are heavily used outside of the automotive industry, especially in jumbo jets and locomotives.

Disc brakes are made up of a rotor, caliper, brake pads and caliper hardware. With disc brakes, the brake fluid coming from the master cylinder is directed to the caliper where it will be pushed against the piston. In turn, the piston will press the brake pads against the rotor or disc fastened to the wheel which will make the wheel stop or slow down.

Through simple physics, we know that a vehicle in motion possesses kinetic energy and it is the responsibility of the car brakes to get rid of this kinetic energy so that the car will stop or slow down. When you have successfully stopped the vehicle, the car brakes will have transformed the energy into heat produced by friction generated on the surface of the brake pads. Over time, this heat causes the brake linings—the surfaces of the brake pads—to wear out, eventually reaching a point where they need to be replaced.

Drum Brakes
The components of drum brakes include a brake drum, brake shoes, backing plate, return springs, wheel cylinder, or a self-adjusting. With drum brakes, the brake fluid will be directed under pressure from the master cylinder to the wheel cylinder. The wheel cylinder in turn forces the brake shoes to get in contact with the drum’s machined surface located inside it.

Once the pressure has been released, the return springs will pull back the brake shoes to a position where they are at rest. With the wearing of the brake linings, the brake shoes are then tasked to travel a much longer distance in order for them to get in touch with the brake drum. Once this distance has reached a particular point, the self-adjusting system will respond and adjust the brake shoes’ rest position for them to be nearer to the brake drum.

The drum brakes’ brake shoes are responsible for converting your vehicle’s forward motion into heat, just like the disc brakes’ brake pads. This heat will eventually cause the brake linings on the brake pads to wear out and need be replaced.

How to Know if You Need Brake Repair
Brakes endure a certain amount of wear and tear every time you go for a drive, making it very important to know when it is time to have the mechanic check your brakes.

Here are some of the most common symptoms and warning signs that may indicate that you need brake repair:

  • When you require greater effort when stepping on your brake pedals to make the car brakes function.
  • When you encounter a severe pressure drop in your brake’s hydraulics.
  • When you apply the brakes, your car pulls or swerves sideways.
  • When you feel that your car brakes “grab” even when you only exert a small amount of pressure when stepping on it.
  • When your entire car, brake pedal, or steering wheel vibrates or shakes when the brakes are applied.
  • When you notice that your car brakes are unusually close to your vehicle’s floorboards when applied, which may lead to the activation of your brake warning light.
  • When your car brakes squeal loudly. In general, a little squealing here and there is not uncommon, but loud noises accompanied by loud screeches are causes for alarm.

The modern, more advanced brake systems that are now used for cars have been refined and restructured numerous times since their inception and have become more efficient, reliable, and durable. They’ve also become harder to maintain and repair.

Since car brakes are important investments for you and your family’s safety, you should have your car brakes periodically checked and maintained by a professional mechanic so you won’t have brake problems.

Additional Resources for Brake Repair: