1) Worn Pads: You'll have to estimate, but generally, your pads should be at least one-quarter of an inch thick. If they're any thinner than that, it's a good idea to get them changed.
2) Strange Sounds: One of the warning signs that your brakes need servicing can come from a small indicator in your braking system that emits a high-pitched squeal when your pads need replacing. And, while this sound is loud enough to be heard even when the windows are up, it might be tough to hear with Lady Gaga blaring from the stereo.
3) Pulling: Has your car ever felt like it has a mind of its own? As if it wants to make right- or left-hand turns while driving or braking? If so, this could indicate a problem with the braking system. Pulling, however, doesn't always indicate a problem with the brakes. The cause could also come from unevenly inflated or worn tires, poor alignment or a problem with your vehicle's suspension.
4) Vibrations: Generally, a vibrating brake pedal indicates warped rotors. Their uneven surfaces will thrum against the brake pads, and you'll feel the feedback through the brake pedal.
5) Temperamental Pedal: A mushy pedal, one that goes practically to the floor before engaging the brakes, could indicate worn pads or a problem with the hydraulic system, such as air in the line, an air leak or a brake fluid leak.
