Under normal circumstances, a squealing from your wheels is a good indication that your brake pads have worn down and require replacement. While this may be the most common cause of squealing brakes, it isn't the only one. If your brakes are squealing, but the thickness of your pads seems fine, then there may be more severe issues at play.
Diagnosing any noise on a car can be challenging, but you're already a step ahead of the game if you've narrowed the source down to your brakes. These three diagnostic steps will help you to isolate the problem further so that you can ensure your brakes are working safely and efficiently.
1. Check Your Pad Wear Indicators
When your brakes squeal, the noise that you're hearing is the wear indicator on the pad. This strip of metal makes contact with the rotor when the pads fall below minimum thickness, alerting you to a problem. In rare cases (often as a result of improper installation), the wear indicator can bend and make contact with the rotors too soon.
If you can get your car into the air and remove the affected wheel, then checking the pad wear indicator is easy. Look for a small metal tab on the edge of the pads. If this tab is in contact with the rotor and your brakes have plenty of material left, then you've found your problem. Bending the indicator may temporarily resolve the issue, but you will need to monitor your pads to know when to replace them.
2. Examine Your Rotors
Rust is another common source of short squeals and squeaks. Your brake rotors are bare metal exposed to the environment, and this means that they will develop surface rust. Rust forms quickly overnight, especially in damp climates or after a rainstorm. The friction from your brake pads will promptly wear down any rust, but your brakes may squeal until all of the rust is gone.
If a quick drive doesn't solve the problem, then check your rotors for signs of glazing. Glazing will make your rotors appear shiny and mirror-like, and it points to a heat issue. In most cases, overheating brakes are the result of a stuck caliper keeping your brake pads continuously in contact with the rotor. Glazed rotors always indicate a severe underlying problem that you should address as soon as possible.
3. Inspect Your Anti-Rattle Clips
Anti-rattle clips prevent brake pads from moving freely in their bracket, where metal-to-metal contact may produce a squealing or squeaking noise. If your anti-rattle clips are damaged or missing, then this is likely the cause of your squeak. Insufficient lubrication on the metal pad backing plates may also cause your brakes to squeak and chirp. Adding more lubrication usually fixes this problem.
Never ignore any unusual sound from your brakes. If you are uncomfortable performing these diagnostic steps yourself, contact local brake repair companies.