Ever count how many times per drive you use your brakes? They are extremely reliable given how often we use them but they have to be maintained and taken care of. Here’s everything you need to know about your brakes. The brake system in automobiles uses hydraulic pressure to press the brake pads against the brake rotors which slow the car down using friction. The entire brake system consists of various mechanical parts, called brake assembly components:
- Brake pedal
- Brake master cylinder
- Brake Fluid
- Brake callipers
- Brake lines
- Brake pads
- Brake drums (what’s the difference between brake pads & drums?)
- Brake rotors
- Brake shoes
- Emergency brake
- Brake sensors (some vehicles)
The problems that you’ll deal with when it comes to brakes include but aren’t limited to the following:
- Squealing brakes
- Rusty brake lines
- Brake pedal goes all the way down
- Leaking brake wheel cylinder
- Sticky brake pads
- Brakes that pull to one side
- Grinding brakes
The best way to know the real issue is to have a certified mechanic diagnose the issue by inspecting it. For example squealing brakes is usually a sign that the brake pads need to replaced but it could also be due to pads not being installed properly.
It is imperative to get your brake system examined even on the slightest doubt owing to its importance with respect to your safety.
Types of Brake Pads
Cars have between 4-8 brake pads in them, with the front brake pads larger than the rear. Brake pads can be made of different materials depending on the application. There is no “perfect” brake pad for all conditions, each has its pros and cons. Brake pads for streetcars are usually one of the following: organic, semi-metallic, ceramic, and sintered.
Organic – Usually the least expensive pads, they are what most manufacturers put on their cars because they are soft, so they’re easy on the rotors and don’t make a lot of noise. They also work really well for commuting for their ability to stop the car when the brakes are cold is very good.
These brakes aren’t good for racing, or any activities that require severe braking because as the temperature goes up their effectiveness goes down and they burn up quickly.
Semi-Metallic – These are more expensive than organic brake pads because of the process involved in the manufacturing of these pads. Compared to organic pads, these pads have a much higher operating temperature and don’t wear out as quickly when put under extreme stress.
Their downside is the fact that they are more abrasive and wear out rotors faster than organic pads. On top of that, they also make more noise and produce heavier dust. Most race cars have semi-metallic pads.
Ceramic – Ceramic brake pads’ biggest benefit is the lack of brake dust and noise. They usually last longer than organic pads in terms of wear while being better for the rotors. They also have a higher operating temperature than organic pads but nothing close to semi-metallic. They are almost a compromise between semi-metallic and organic.
To summarize, if your car is a regular street car you should get organic or ceramic brake pads. If you’re racing or tracking your car then you should look into semi-metallic or sintered pads.
The rotors (also called discs) are what the brake pads grab to stop the vehicle. Just like we brake pads, we have different types of rotors each with their own benefits and drawbacks. There are regular rotors, drilled rotors and slotted rotors with varying levels of heat displacement.
Regular rotors – These are the regular rotors that you have on almost all cars.
Drilled rotors – These rotors have holes drilled into them. Drilled rotors have the benefit of letting heat escape more easily than regular rotors. Another benefit is they prevent gas build between the pads and rotors, even though this is isn’t an issue with newer pads. The last reason is water and wet conditions, the holes allow water to be easily be removed on the rotor’s surface.
The disadvantage of the drilled rotors is the weakened structural integrity of the rotors.
Slotted Brake Rotors – Instead of using holes as drilled rotors, slotted rotors use slots carved into the rotors which allow heat, gas and water to move out of the way. These are popular with high performance cars in demanding conditions because they are more durable than drilled rotors.
The disadvantage of these rotors is that they wear down the brake pad quickly which is why most manufacturers use drilled rotors.
Types of brakes and break systems:
Disc Brake: Disc brake is a mechanism for deceleration of the wheel of a car. Usually made up of cast iron, in some cases components like carbon-carbon or ceramic-matrix composites are also used. The disc is connected with the wheel. Friction caused by the brake pads on both sides of the disc forces it to slow down or stop. Disc brake is probably the most known type of brake.
Drum Brake: Drum brake is the conventional break wherein the friction that is responsible for stopping or slowing the car is caused by a set of brake shoes or brake pads. These brake components press against the inner surface of the rotating drum. Due to friction, these brake shoes get worn off and need replacing. Although its use is getting less and less every year, 70-80% vehicles’ front wheels are still equipped with a drum brake.
Air Brake System: An air brake, also called a compressed air brake system, is a complex system. It is a friction brake for vehicles in which the piston, pressed by the compressed air, applies the required pressure to the brake pad that is needed to stop the vehicle. Air brake system is mostly used in vehicles having multiple trailers which must all be linked into the brake system.
This categorically involves heavy vehicles like trucks, buses, trailers, etc. An air brake system is compatible to work with the designs of foundational brake subsystems, even on the same vehicle. While most of the truck air brakes are drum brakes, recent trend shows a high interest in the use of disc brakes.
Although air brakes cost more and require higher maintenance, they have a major advantage over the other brake systems. Since the supply of air is unlimited, the air brake system never runs out of its operating fluid. Therefore, it is safer than hydraulic brakes and minor leaks do not fail the brakes.
The components used in an air brake system are control pedal, air storage tank, service brakes and parking brakes.
Parking brakes: A disc or drum arrangement is designed to be held in the applied position by the spring’s pressure. These spring brakes are released by the produced air pressure.
Service brakes: When the brake pedal is pushed, the pressurized air moves to the air brake chamber. The air brake chambers are mounted in a fashion so as to face their pushrods inwards towards the brake shoes and drum. This engages the brake.
Foundation brake subsystems are of three types: S-cam brakes, disc brakes and wedge brakes.
“S” cam brakes: As far as commercial vehicles with air brake systems are concerned, “S” cam brakes are the most common type of foundation brake.
Wedge air brakes: The wedge air brake system is a type of drum brake that includes brake drums and brake shoes with no exposed brake linkage.
Frequently Asked Questions
When should I get my brake pads replaced? or How often should I replace my brakes?
You should replace your brake pads when the pads have less than 3 mm thickness left. In most cars you will hear a squealing noise when you press the brakes and in other cars you’ll also have a sensor that tells you so.
It’s imperative you do get your brake pads replaced as soon as possible, driving with worn-out brake pads is dangerous and can lead to very expensive repairs. Other warning signs that you need new brake pads including the brake pedal being lower than normal and vibration in the steering wheel.
Antilock Braking System (ABS) is installed in most modern vehicles as a system to prevent the brakes from locking up when they’re pressed too hard for the conditions.
For example, if it’s slippery outside due to ice and you press the brakes, without the ABS system they would immediately lock up. With ABS the system would prevent that by applying a “pulse” to the brakes instead which allows you to steer the vehicle at the same time.
When should I replace my rotors?
It all depends on the thickness of the rotors which the mechanic will inspect. Usually, rotors are replaced once every 2 brake pad changes, provided you didn’t drive with worn-out brake pads. Symptoms indicating that you need to get your rotors replaced include
- Grooves/hot spots in rotors
- Vibration or pulsation when brakes are applied
- Blue discoloration of rotor surface
Ignoring this repair may cause rotors to thin out or become warped in which case the rotors will be unable to dissipate the heat caused by the system effectively. This may cause the braking fluid to boil and reduce the effectiveness of the braking system.
How often should I change my brake fluid?
At InstaMek we recommend you change your brake fluid as often as your vehicle’s manual recommends. You can even test your brake fluid as often as you like for copper and air to see how much life you have left.
Related: Read about the different types of brake fluid.
My brake light is on, what does that mean?
If your brake light comes up, it means the following depending on your vehicle:
- The brake light is out
- ABS sensor is sensing something wrong or is malfunctioning
- Brake pads are low
- Battery voltage is low
- The brake fluid is low
- The parking brake is on
You should call a certified technician to check on the problem before driving the car after checking the brake fluid level and parking brake. You can look in the owner’s manual of your vehicle on how to check the brake fluid level.
Few of us think about our brakes on a daily basis, but they are a critical component of a car and can mean the difference between life and death in an emergency.
Proper maintenance and a quick response to warning signs will ensure that your car will stop every time you hit the brakes. Get your vehicle’s brakes inspected and repaired by our expert mechanics.