Brakes are such a crucial part of the car, having them squeak can be both annoying and worrying. This is especially true if the squeaking continues for a long time or gets worse and worse. With that being said, noisy brakes are common and can often easily be dealt with by any auto mechanics shop.
Most automobile brakes today are disc brakes. This is where a pad presses against a disc (also known as the rotor) in order to stop the car. Some cars utilize an older type of brakes known as drum brakes. Sometimes, even on modern cars, the rear wheels will use drum brakes due to cost consideration. This type of brake uses a curved part called a “shoe” to press against a hollow drum, which then stops the car.
Often brakes will squeak after sitting all night. This is typically because of moisture from rain, dew or condensation that accumulated on the surface of the rotors. A thin layer of rust builds up on the surface of rotors. As the rotors turn the pads scrape off this rust. These fine particles can get trapped in the leading edge of the pad and can cause a squeaks.
Thinning Brake Pads
All pads have a built in wear indication. As the pads are used, they become worn, eventually thinning to the point of where the wear indicator becomes audible. This is a very common source of squeaks but it is not a failure, it is simply an indication that it is time to have the brakes serviced and pads replaced. These wear indicators are just small metal tabs made of steel which hit the rotor when pads are too thin, generating the noise.
High Metal Content
Certain low end pads can be manufactured with a high metal content. There may be large chunks of metal embedded into the pads. These pieces will drag on the rotor and cause a high pitched brake squeak. Ideally brake pads with a higher content of non metal materials should be used. This will minimize the squeaks.
Drum Brakes Need Lubrication
If squeaking is heard from the drum brakes, it is an indication that they need to be lubricated. Shoe to backing plate contact points have lost most of their lubrication and thus need to be serviced.
Scraping From Plate
If squeaking is heard during regular driving, it may be an indication of scrapping from a plate due to damage. The typical cause of this is due to a rock hitting the underside of the car.
Brakes are one of the most important functionality of a car. It's important to know when they need to be serviced, replaced, or repaired. Have your trusted car care professional check them out if you ever have any doubt.
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