Wouldn’t it be great if our cars told us when something is wrong? In a way, they already do. Modern cars have instrument panels with dozens of symbols and warning indicators. These notify you of basic issues, like low windshield washer fluid, as well as possibly dangerous problems.
Cars make a lot of noise, but there are a few telltale noises that signal your brakes are the culprit, and certain types of brake noise spell trouble. Here’s what the different noises mean.

1. Squealing brakes when brakes are not applied.

When you step on the brakes, you expect to hear some noise as you begin to decelerate. The brake linkage may creak, the brake booster may huff, and the tires may complain a little if you are really stopping hard. What’s disconcerting is when the brakes squeal and your foot is not pressing on the brake pedal. In all likelihood, a brake pad needs replacement.
Most of today’s brake pads come with wear indicators, a small metal protrusion attached to the pad’s backing plate. Before your pads wear out, the indicator comes in contact with the brake rotor or disc, making a squealing noise.
In this case, brake noise serves as a warning to replace the pads now or risk a more costly repair later when the pads are gone and a metal backing plate comes in contact with the brake rotor. Check all four wheels for signs of wear.

2. Squealing brakes when the brake pedal is applied.

What if you hear the squealing noise when you step on the brake pedal and as you come to a stop? As with the first example, your brake pads may be shot and the wear indicator is telling you it is time to replace your pads.
But don’t fret: Sometimes the squealing is telling you that a build up of brake dust is present and simply needs to be removed during a brake inspection. Drum brakes in particular can be affected by brake shoe dust. During a brake service, your technician will be checking and cleaning the drums: this can do wonders. Your brakes may never be squeak free, but with the dust removed, they’ll be quieter to the touch.

3. Screaming brakes when the brake pedal is applied.

When you step on the brakes and you don’t hear squealing, but instead a more vigorous and loathsome noise, one that puts your teeth on edge and gets the attention of everyone nearby, it means that the brake wear indicator warning has been superseded by metal on metal contact. The brake pads are worn down and the metal backing plate is now rubbing up against the brake rotor.

Guess what? This is a serious safety issue. Take your car to a mechanic. You can also expect to be informed that the rotors will require resurfacing. In a worst case scenario, damage to the rotors may be so severe, it’s time for replacement.

Beyond Brake Noise

Brake noise is not the only indicator of trouble. If the vehicle pulls to the left or to the right when you brake, it may point to a possible alignment issue. Shaking that happens only when applying the brakes can indicate a warped rotor. Also, if the brake pedal feels spongy to the touch or travels closer to the floor than usual, the master cylinder may be giving out. It could be something else, but neither problem should be ignored and, for a precise diagnostic, you should rely on a qualified technician, since your safety is at stake.
For more information on brake noise, chat with an expert at your local NAPA AUTOPRO service centre.