What is brake pad squealer? A squealer is a small piece of metal attached to a brake pad that comes into contact with the brake rotor, making a squealing sound when the brake pads are worn down. This noise serves to alert the driver that the brake pads need to be replaced as soon as possible as they are reaching the end of their service life.

Braking System Explained

To understand brake pad squeal, it makes sense to go over some of the basic “anatomy” of modern car brakes. A disc brake consists of a caliper, pads, and rotor, along with attached lines to supply brake fluid. Let’s look at the caliper, pads, and rotor in turn to see how they function together and how you end up with that horrible squealing noise! 

• Caliper. The brake caliper is a component that is mounted on the rotor and holds the brake pads. In many vehicles, these are a solid gray color. On many sports and performance cars, you might notice colorful calipers, such as green or red, with large logos on them such as Brembo or Akebono. Both these and the solid gray calipers serve the same function, to help squeeze the brake pads against the rotors (although the bigger calipers on performance cars is usually to handle the increased demands for stopping). 

• Pads. Brake pads sit inside the caliper and grip the rotors to stop the vehicle. There are many different compounds used in brake pads, from metallic and semi-metallic to organic kinds available. Most passenger vehicles use a semi-metallic brake pad, however. Each caliper will house two brake pads, one for each side of the rotor. Naturally with use the pad material will wear down. It creates friction to stop, thereby stripping away some of the pad’s material when you brake. 

• Rotor. A brake rotor is a disc shaped piece, hence the name disc brakes. They have the caliper mounted atop them, and the brake pads come into contact with the rotors when you press the brake pedal, helping slow the vehicle to a stop. Usually, a brake rotor is made of iron and is a solid silver color. Over time, however, the rotors will become rusted and lose their shine. 
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Brake Pad Squealing Noise

When you hear a squealing noise when you apply your brakes, from either the front or rear or your car (or both), it is likely the metal tab hitting the rotor. Not all brake pads have this tab, however. So you might not necessarily get an audible warning when your brake pads are worn down, which is why regular inspection of your brake system is recommended. 

Once you hear this squealing noise, there is no reason to try any method other than replacing the pads to solve it. While the sound is no doubt annoying, it signals a potential safety issue and needs attention; trying to lubricate your brakes, while it might temporarily change or reduce the noise, will only lead to more problems down the road.

When brake pads are worn and squealing, it is also important to have them replaced to avoid the need for additional repairs. The thinner they get, you also run the risk of warping your rotors. If the pads are worn down and you brake, excessive heat and friction will be generated when they contact the rotor, which can damage it. 

Rotors, like pads, do wear down over time and need replacement, but they do not need replacing as often as brake pads themselves, and they are more costly to replace, whether you do it yourself or have a service center do it. In other words, it is in your best interest to service your brake pads in a timely manner, not only for safety but to protect your rotors from early failure. 

Other Signs of Worn Brake Pads

There are also several other symptoms of worn brake pads to know about. 

• Steering wheel vibration. When the brake pads are worn, you might notice that your steering wheel vibrates during braking. While a shaky steering wheel can also be a sign of other issues, it is worth considering brake pads, especially if you have any of the other issues pointed out here.

• Brake pedal vibration. Along with a vibrating steering wheel, the brake pedal itself might shake whenever you press it. This is alarming and can impact your ability to brake as the pedal itself it moving without your input!

• Car is unstable. You might feel the vehicle pulling to one side or the other when you apply the brakes. If this is related to worn brake pads, and not something like worn suspension or poor alignment, it will be because one side’s pads have more wear than the others, causing the vehicle to shift one way or another. 

• Grinding noise. If, rather than a squeal, you hear a grinding when you press the brakes, this signals that the brake pads are completely worn down. The grinding noise comes from the metal of the bare pads contacting the rotors. This will damage your rotors if you continue to drive on them, and of course your ability to brake will be dramatically reduced. 

• Takes longer to stop. This one is a little subjective and harder to tell, but you might feel that you are taking longer to stop than you used to. As the pads wear down, they will become less efficient. This can be particularly dangerous in wet conditions when braking distances are already increased due to the inclement road surfaces. 

What To Do If Your Brake Pads Are Worn

As noted, worn brake pads are a safety issue and can increase your risk of getting into an accident. You need to have them replaced as soon as possible. 

It is also a good idea to have the entire brake system inspected at this time. You want to make sure your rotors are in good condition, and if not, have them replaced. Have the calipers and brake lines checked, as well as the condition of the brake fluid itself. 

The brake pad squealers should never be removed.