Brakes pads are an essential part of a car’s vehicle brake system. You can find them between your brake shoes and brake drum. When the brake pads are no longer working properly it will wear down other elements of the brake system including the rotors, discs and calipers. Keeping brake pads in good condition is a must to avoid very expensive repairs and unsafe driving conditions. So knowing how to identify when to replace a car’s old brake pads is very important. But first, why do brake pads wear?
Brake calipers which looked like big, adjustable clamps squeeze your brake pads against the brake rotors causing the car to slow down and stop. When you press the brake pedal, it makes the calipers clamp down on the brake pads which compress the rotors thereby transferring the kinetic energy of the vehicle into thermal energy also known as heat by friction. The resulting friction is what cuts the speed and brings your car to a stop. Each time the pads rub against the rotors, they wear down little by little. You might have noticed some black dust on the wheels of some vehicles. This black dust is the residue from the material of the pad and steel rotor that has worn off. Brake pads are an important part of a vehicle’s disc-braking system and making sure they are working properly is a must for your safety.
Screeching Noise
One of the first indications is when you hear a screeching noise or squeal when pressing the brakes. What you can hear is a sound produced by a thin metal strip in the pads. It is purposely embedded in your brake pads to let you know that they are worn to the point of needing replacements. You can easily hear it when the windows are up but it may be masked by surrounding sounds like loud music and other noises in the environment. Not all vehicles have this feature though so better check to see if yours does. It is called a “mechanical brake-wear sensor” or a brake scraper. When you are hearing it on a regular basis then it is time to bring your vehicle for an inspection. Rain or storm can expose your brakes to damp conditions. When this happens a thin layer of dust may form on the brake pads and cause a very similar squealing noise while braking. If the noise disappears after the first few times you engage your brakes then that’s a good sign that the culprit is just a bit of rust built up on the brake pad and you do not need to have your brake pads replaced.
Less than ¼ INCH Brake Pad
You can also conduct a visual check up to see if your brake pads are in need of replacement. What you can do is to look through the tire spokes and you should be able to see your brake pad squeezed against your brake rotor. It should be at least a quarter of an inch thick (or 3 millimeters). If it is less than that, then consider bringing your car to a brake specialist especially when it has been a long time since the last inspection. Most likely it is time for their replacement. In case you cannot see the pad by looking through the tire spokes, you might need to jack up your car, then take off a front wheel and check for pad wear. Bolt the wheel back on, jack up the rear of your car then remove a rear wheel and inspect for a rear brake as well. You might need a flashlight or trouble light so you can see clearly in the dark fender wells. Since you already went into trouble checking some of the brakes, you might as well check all four brakes.
Deeper Grinding or Scraping Noise
If the noise you are hearing sounds like metal grinding or a rumbling growl, chances are your brake pads are already worn down to their metal backing plates and to the point that those plates are now being compressed directly against the steel brake discs. This is a very dangerous situation as it can reduce the vehicle’s stopping power significantly. Your brakes will not be able to slow your car adequately or even not at all if you ignore this issue for any period of time. This condition will also damage your brake discs and can lead to a complete brake system failure. So when you hear any grinding noises you have to check your brakes immediately. Bring your vehicle into a service shop to avoid bigger problems.