Gimme A "Brake": 5 Facts About The Pads On Your Car
Posted on: 29 January 2015
Every time you bring your car to a stop, you call on technology that has actually been around for more than a century. Here's a look at five facts about automotive brake pads--those miracles of stopping power that you may take for granted.
1. Who Invented Disc Brakes?
A basic version of the disc brake that is used on automobiles today has been around since the late 19th Century. Englishman Frederick William Lanchester received a patent for the disc brake in 1903.
2. How Do Disc Brakes Work?
Disc brakes work by applying friction against the wheel of the car. When you apply your brakes, the brake pads rub on the brake discs (AKA rotors), which are connected to the wheels via the car's axle. Kinetic energy is thereby turned into thermal energy. This is why it's important to have brake pads that can withstand high temperatures.
Components in the brake pad conduct heat away from the rotor. If brake pads aren't replaced as often as they should be, there can be wear on the rotor, which produces grooves called "scoring." When this happens, the rotors may need to be replaced.
3. What Are Brake Pads Made Of?
Brake pads used to be made of asbestos, as this absorbed heat and noise very well. However when the health dangers of asbestos became known, brake pads were then made of carbon, and later semi-metallic materials that are still used today in most cars.
Semi-metallic brake pads are made of chopped steel wool and resins. The more finely chopped the steel, the smoother the pad is and the higher its price tag. Smooth pads produce less dust that can mark your wheels. Semi-metallic pads are good at reducing brake "fade," a condition where the brakes are too hot due to not conducting heat well.
There are also ceramic brake pads that use copper to conduct heat from the disc. These are good at reducing noise and dust and are most often found in heavy vehicles, some luxury cars, and race cars.
4. How Do You Know When Your Brake Pads Need Replacing?
There are a number of indicators that your brake pads are due to be replaced:
- high mileage
- heavy use, as in lots of city driving versus highway driving where you don't brake very often
- lact of effectiveness (can't stop short, need to apply the brake pedal from further away, etc.)
- noise (clicking, squealing, or screeching when car hasn't been sitting long or brakes aren't damp)
- wear indicator on the pad reveals metal
- vibrating or pulsating brake pedal
5. Can You Replace Your Own Brake Pads?
You can replace your own brake pads if you're comfortable removing tires and understand the brake mechanism. Some people say DIY brake pad replacement is easier than changing your oil. You might want to run the job by a mechanic, however, if it's your first time, and definitely have the pads replaced professionally if there's any doubt that you can do the job perfectly.
Your car's brakes and brake pads are really a miracle of modern engineering. They have to work in the cold, in the heat, after heavy driving, and in rain, ice, and snow with a minimum of noise and dust. The next time you get yours replaced, you can appreciate the 100-plus years that have gone into their technology.
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