The best prevention is regular maintenance. Have your car's brakes checked at least once a year, more if you drive frequently in city traffic or live in a hilly area. If you wait until you hear grinding noises coming from the brakes, you'll be spending extra money on your next brake job. Here are some things to check if you suspect brake problems.
Make sure you're not driving with the parking brake on.
Get the brakes checked if you hear a high-pitched squeak that goes away when you step on the brakes. This noise comes from a brake-pad sensor--a soft piece of metal that scrapes against the brake rotor when the brake pads need replacing.
Check the brake-fluid level (see How to Check and Add Brake Fluid).
Bring your car to a mechanic for a brake check if the brake master cylinder is consistently low on brake fluid. If you need to add brake fluid more than once every few months, there is probably a leak in the brake system.
If the pedal slowly sinks down to the floor when you brake, you may have a bad brake master cylinder.
If the pedal feels soft and mushy but gets harder when you pump up and down, have your mechanic bleed the brake lines to remove any air pockets in them and check for a faulty brake master cylinder.
If the brakes pulsate when you step on them, your car may have warped rotors, which can affect stopping ability. Have your mechanic check them.
If the brake pedal sinks to the floor or gets soft when you're using the brakes on a long, steep downhill grade, the problem could be brake fade. This occurs when the brake fluid gets so hot that it boils. Your mechanic may not find anything wrong with your brakes because the problem disappears after the brake fluid cools down.
