Using Your Ears, Hands And Feet To Determine If Your Brakes Are Going Bad
A good indicator to know if your brakes are wearing is to let your ears, hands and feet be the indicator. When you apply the brakes and you feel or hear a grinding noise there is a good chance your brake pads have worn down to the metal and will need to be replaced before further damage is done. There is a good chance more damage has been done other than just needing brake pads replaced. The other problem that can occur when you hear your brakes squealing is an object or piece of road debris is stuck between the rotor and the pad. If you feel the steering wheel shake when you put on the brakes, this is an indication that you probably have a warped rotor. A warped rotor is caused by applying your brakes for a long period of time.
If the brake pad has worn down to the metal it will damage the rotor and you will need to have it replaced or machined. To check and see if this has occurred, you can run your finger across the rotor. The rotor should be as smooth as glass. If you can feel groves in the rotor then it will need to be machined. By not machining the rotors if they are bad and just replacing the brake pads will create uneven wear on the pads and your car will have a vibration every time you apply the brakes.
Every car is going to wear down its brakes at a different rate. Many times break wear is determined by your driving habits. Someone who brakes a lot or is always coming to an immediate stop will wear there brakes down faster than someone who is more cautious in using there breaks. Regardless, make sure you get your brakes serviced once you can tell a noticeable difference in braking power. Failing to do so could be deadly.