If you neglect brake pad maintenance for too long, you'll have to have the brake rotors machined or maybe even replaced.

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When to Change Brake Pads

Above all else, remember this: It's dangerous to wait too long to change your brake pads. As the brakes are applied repeatedly over thousands of miles, the brake pads gradually wear down, reducing their ability to stop the car. But how do you know when it's time to change your brake pads?

­Luckily, it's not difficult to determine when your vehicle is ready for some brake work. Disc brakes usually include a part called a wear indicator. A wear indicator is a small piece of metal attached to the brake pad that contacts the brake rotor when the pad material has been worn down to a certain level. When the wear indicator grinds against the rotor, it makes a squealing noise as you apply the brakes. This noise is a signal which tells you it's time to have your brakes examined.

In other words, noisy brakes aren't something to mess around with. If you hear that sound when you apply the brakes in your vehicle, have them checked out as soon as possible.

If you're fixing brakes yourself, there are other signs to look for as well. If the brake pad is severely worn down, it can leave deep, circular-shaped marks and grooves in the brake rotor. Those marks, called scores, look a lot like the grooves on a record and are a sign that the brake pads need to be replaced. If the scoring on the rotor is particularly deep -- from lack of timely maintenance -- the rotor itself may need to be swapped out with a new one. If the grooves don't run too deep into the surface of the rotor, you may be able to have them turned (or machined) to give the rotor a new, smooth surface. Typically, turning a set of rotors costs less than replacing a set of rotors.

While you're looking at the pads, it's also a good idea to inspect the brake lines for cracks and holes. If there is a fault (or leak) in any of the brake lines, you could experience a loss in pressure and your brakes won't work properly -- they may even completely fail. Don't forget to take a good look at the fittings, too. The brakes are supposed to be sealed at this end of the system, so you shouldn't see a drop of brake fluid anywhere near the wheel. If you do find a leak, try to locate the source. Depending on your abilities, you can either fix the leak yourself or have it repaired by a professional. Either way, repair it as soon as possible. Even a small leak in a hydraulic brake system can be very dangerous.

Your brake pads should last tens of thousands of miles, but that depends on the specific vehicle you drive and your own driving habits. The more you use your brakes, the shorter the lifespan of your brake pads. When it comes time to fix them, don't be afraid to do the brake repair yourself.

Up next, we'll tell you how to get your vehicle ready for the new pads.