Why Do My Brakes Squeak & How Do I Fix Them?
Has this ever happened to you? You’re driving in your car, slowing down as you approach a stoplight, when suddenly you hear a shrieking squeak which seems to pierce the eardrums of everyone on the road. Even worse, this terrible noise is coming from your brakes!
What causes brake squeaking, what potential problems could the noise indicate and how can these problems be fixed? Here’s what you need to know:
What are Squeaking Brakes Trying to Tell You?
Generally, brakes have a lot to say. Even when working perfectly, the brakes in your vehicle will make noises – sometimes weird ones – from time to time. In the overwhelming majority of situations, squeaking brakes don’t represent any brake failure or other dangerous situation. Squeaky brakes can still stop your tires as well as quiet brakes.
But brake sounds aren’t meaningless, either. Each one tells you something specific about your vehicle. Deciphering those noises can help you diagnose any potential problems and otherwise keep your brakes in great shape.
Two Types of Brakes
Cars and trucks can have one of two types of brake systems. Disc brakes are the most common. This system stops the car by pressing a brake pad against a disc or rotor. Generally, disc brakes make quite a few noises as part of normal operation (we’ll explain why later on).
The other type of brakes are drum brakes. They’re far less common, mainly only found in older cars. Drum brakes use a curved shoe to press against a hollow drum. These brakes are found on the back wheels. There are certain squeaking noises which you’ll only hear on drum brakes.
Why Do Brakes Squeak?
Brakes speak their own language. Every sound means something specific. You’ll need to consider the specific sound as well as any other contextual clues. Here are some common reasons brakes might make a noise:
Rain, dew or condensation can all cause disc brakes to squeak. Moisture builds up on the brake rotors, which creates a thin layer of rust. As you start to drive, the rotor turns, causing the rust to scrape off against the brake pads. As microscopic particles of rust become temporarily embedded in the brake pad, a squeaking sound occurs.
If you park your car outside, you’ll likely hear this noise on your morning commute after a rainy night. Occasional, temporary noises are usually nothing to worry about. However, consistent exposure to heavy moisture can cause excessive rust buildup, which in turn results in layer becoming scraped off the rotor. If the rotor is too thin, it’ll actually look blue.
Unfortunately, the fix for this problem is both simple and complicated. You’ll need to park your vehicle indoors in a dry place. That’s pretty much the only way to prevent damage from consistent moisture exposure.
Thin Brake Pads
Brake pads naturally wear down over time. The exact rate will depend on general driving frequency, road conditions and other factors. But eventually your brakes will wear down. When they’re just about worn out, they’ll make a high-pitched warning sound.
This sound is purposefully made to grab your attention. Manufacturers put small, steel tabs into the brake pad. Different manufacturers put them in different places near the brake pad, but the basic function is always the same. When the brake pad has worn down significantly, the steel pad will hit the rotor, creating a noise meant to alert you to an issue.
This brake sound indicates a serious problem is on the horizon. The brake pad is very thin, and soon the braking will involve just metal on metal. If that happens, brake function can be severely impaired.
Not sure if the noise you’re hearing is the sound of a thin brake pad? Generally, this noise will be most intense when you’re gently applying the brakes. If you press the brake down fully and quickly, the squeaking will usually stop.
The fix for this problem is usually as simple as replacing your brake pads.
Brake Pads with High Metal Content
All brake pads contain at least some metal bits. But poor-quality brake pads can contain too many. If your brake pads have too much metal, they will likely drag against the rotors. This causes a high-pitched squeak.
Brake pads with a high metal content are no good for two reasons. First, they wear down quickly. While your pads likely won’t be dangerous right away, their decline is inevitable. Plus, the sound can be incredibly annoying, especially if you have to hear it day after day.
Better brake pads are the solution here. You’ll want to use pads mainly made from organic brake materials. This includes resin, rubber, Kevlar and similar (“organic” has a slightly different meaning when referring to brake pads). Organic brake pads will have significantly fewer metal shavings and particles than cheaper pads.
Drum Brakes Which Require Lubrication
This situation is only relevant for drum brakes. You’ll know something is wrong if you hear squeaking from the rear of your car after pressing down on the brake pedal. The sound means the contact points on the backing plate need lubrication. Otherwise, the metal will begin to rust. If that occurs, you’ll hear a squeaking noise whenever the back wheels rotate.
To fix this issue, both the contact points and caliper pins will need to be lubricated. Special drum brake lubricants are available for this situation. If you’re not sure what to do, contact an automotive professional for help.
All in All
Modern brakes use a variety of metallic and ceramic materials which can make noise, especially when the car is first warming up and the weather outside is filled with moisture. But just because some squeaking noises are relatively common doesn’t mean you can safely ignore brake noises.
Instead, you’ll want to identify the source of the noise and then correct the issue quickly. Your brakes will tell you when something is wrong. The best way to keep your brakes in safe working condition is to always listen to what they have to say.