Brakes Brake Noises Whistling Sounds from Brakesbrake Repairsautomotive Repair
You press the brake pedal in your car and you hear a noise. What can this mean? Depending on what the noise is, it can mean several things. If it is a whistle or a whine (which will sound similar inside the car) it can be caused by one of several things. Luckily non of these are actually life threatening at the moment. Don't take that to mean that you should ignore it, you still need to find out what is causing the noise.
By reading this article, you can narrow down the causes of the sound and therefore decide how to fix the problem.
As with any kind of problem, and especially the automotive type, start with the simplest answer first. Just because there is a whistle or whine, it doesn't mean that you have to run out and spend hundreds of dollars to have the entire braking system replaced.
1. Has the car been sitting for any length of time, especially if it has rained? The rotor (which is the metal disk that the brake pads rub against to stop the car) gets worn down by the action of the brakes. It is very common for rust to form on this metal disk. The whistle that you hear may be the brake pads "sanding" off that rust so that it is back to bare metal.
2. Have you driven through any water or in the rain? Just like the belts that turn the pulleys on the engine, getting water between the brake pads and the rotor can cause the brakes to emit a high pitched sound. Just like the rust, the noise will go away after the brakes have been used a couple of times. In the case of water, the heat build up from the friction will cause this to happen very rapidly. Usually by the second or third stop light the noise should go away. As a caution, remember, brakes work on friction. If there is water between the rotor and the pads, it can increase the distance needed to stop your vehicle.
3. Did you run over any kind of debris or small tree branches? It may seem trivial when it happens but it can cause the brakes to make noise. Something as small as a twig or a piece of plastic that gets caught in the braking system can cause a whistling sound. By the nature of the design the calibers (the metal brackets that hold the brake pads) have holes in them. These help you to visually inspect the pads as well as let air pass into the system and cool the brakes. If a piece of debris is stuck in one of these holes, it can cause your whistling sound. Even without any kind of debris, the very wind passing over these openings could possibly cause the sound as well.
4. Brake pads have a small metal tab on them. What is the purpose of these? Ironically, their purpose is to cause a high pitched whine or whistle. When you have neglected to change your brake pads when you should have (don't feel guilty, enough people do it that the automotive industry has put this fail safe in place) these metal tabs let you know it is time. When the hard metal makes contact with the metal rotor it causes the noise in question, whether you call it a whistle a whine or a screech. Whatever the description it is still a noise that grabs your attention and means that you need to have the brake pads replaced.
This is a short list of 4 things that can cause the whistle in question. No matter what may cause the sound, if it doesn't stop within a very short amount of time, have the brakes checked by a knowledgeable mechanic. Brake failure is very dangerous to both you, your passengers, and anyone else that is sharing the road with you.
