The mechanics at your local Atlanta brake shop speak a unique language. Understanding brake terminology will help you keep everything in top working order, so your car stops on a dime, every time.
All brake systems work by turning the force of your foot on the brake pedal into hydraulic pressure. The brake pedal operates the master cylinder, located under the hood, which puts pressure on the brake fluid and sends it through flexible pipes called brake lines to operate the brakes at all four wheels.
There are two types of brakes: disc and drum.
- Disc brakes are found on the front wheels of every modern car and on the back wheels of many newer cars. They slow the car by squeezing the brake pads, which is made of a grippy high-friction material, against a metal disc mounted to the inside of the wheel. The squeezing is done by the caliper, which holds the brake pads a few millimeters away from the disc until you push the brake pedal.
- Drum brakes were state of the art before disc brakes became common in the 1970s, and they are still used on the rear wheels of many cars. Named for their (slight) resemblance to a drum--imagine a small snare drum laying on its side, mounted behind the car's wheel--these slow the car by pressing the brake shoes (the drum equivalent of a disc brake's pads) against the inside of the drum.
Maintaining your brakes
Brake pads and shoes wear down with use, requiring replacement. On many cars, the brakes will make a squealing noise when the pads or shoes must be replaced.
If a brake disc gets overheated during heavy braking, or if a hot disc gets splashed by cold water during wet weather, the disc can become warped. Since the surface of a warped disc is no longer flat, it will cause a shaking vibration whenever the brakes are applied. If the warping is mild, the discs can be machined, grinding off enough metal to create a flat surface. If the disc is heavily warped, or if it has been previously machined, it may not be possible to grind it flat again, requiring the disc to be replaced. Drum brakes can also vibrate when warped or out-of-round, requiring machining or replacement depending on the severity of the damage.
A properly functioning brake system keeps the brake fluid completely closed off from the outside environment. If a leak develops anywhere in the system, the brake fluid level will drop, and the brake light on your dashboard will light up. If your brake light turns on, get to a mechanic or brake shop as soon as you can.
Any air bubbles in the system will reduce the pressure of the brake fluid, making the brake pedal feel soft under your foot. This problem is solved by bleeding the brakes, which flushes any air out of the hydraulic system. The brakes should be bled any time a repair is done.
For more information on brakes, visit your Atlanta-area mechanic.