Imagine this:
You’re driving down the highway with your favorite song blasting, and suddenly your brakes let out a high-pitched squeal.
Talk about a brake-induced symphony!
You may wonder, “What’s up with those squeaky brakes?”
When the contact between your brake pads and the brake disc is compromised, your brakes emit a high-pitched squealing noise. Squeaky brakes are an annoyance and could be a sign that your brakes desperately need some TLC.
Cars have two main types of brakes; disc brakes and drum brakes. Each has its quirks and possible causes for squealing — and that’s what we’re here to find out. In this article, we’ll cover eight possible reasons why you have squeaky brakes and what to do about it.
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Let’s jump right in!
The 8 Most Common Causes Behind Squeaky Brakes
Here are eight reasons you may have squealing brakes:
1. Exposure to Moisture
The most common cause of squealing brakes when you step on the brake pedal, is moisture. If your car brakes are exposed to water, rain, or high humidity, a thin rust layer will start forming on the rotor.
When your brakes get wet and squeal, don’t panic! That’s just normal brake noise.
When you hit the brakes, your brake pads scrape off the surface rust on the rotor, causing that awful squealing sound. Slight rust formation overnight is nothing to lose your head over. After a couple of miles of driving, your brakes will return to normal.
How to fix:
Prevent any long-term exposure of your brake pads to moisture.
Excessive rust build-up creates imperfections on the surface of the rotor, which is transferred to the brake pads while driving. The resulting screeching or thumping sounds of squeaking brakes and possible vibrations from an uneven rotor surface are pretty unpleasant.
2. Lack of Lubrication
Most new cars have disc brakes. Some older models still have drum brakes at the rear, and so do vintage models but all around.
If your brake shoe to backing plate contact points (in drum brakes) aren’t adequately lubricated, they’ll begin to rust. The brake shoe will scrape against the backing plate, which creates the telltale rhythmic squeaking noise as the tires rotate.
How to fix:
The best way to prevent squealing noise and brake noise is to do regular maintenance and keep the contact points lubricated with brake grease.
Be sure to use high-quality lubricant on all brake pad contact points but not on the brake pad itself. If you’re not sure how, give your mechanic a call, and they’ll put an end to the brake squealing in no time.
Note: Don’t get brake lubricant (like brake grease) mixed up with brake fluid. Brake fluid is the hydraulic fluid in your brake lines that helps transfer braking pressure.
3. Exposure to Extreme Cold Weather
When it’s below freezing, a layer of ice can form on your brake pad. While this doesn’t affect your braking ability or safety – there’s an annoying squealing noise when you brake.
Driving through dense snow or water will increase the intensity of the squeaking brakes, and the build-up layer will grow. It’ll take longer to wear off, but the icy layer and distracting squeaking sound will disappear as your noisy brakes heat up.
The moisture can, however, cause a thin rust layer to form on your brakes, but this friction material will wear out after a bit of braking.
How to fix:
Consider parking your car in a garage or keeping it covered overnight. You can install a block heater to warm the engine and other mechanical components of your vehicle, including the brakes. Letting your vehicle idle for a few minutes can also help the engine and brakes to warm up.
Thankfully, drum brakes and disc brakes that squeal when they’re cold shouldn’t be worrying — when it comes to the integrity of your brakes or the safety of your car.
4. Worn-Out Brake Pads
Squealing brakes are perfectly normal when brake pads wear down after years of use.
Most disc brake sets have a wear indicator attached to the inside and will make contact with the rotor surface before the pads are completely worn. When your car brakes have worn brake pads, you’ll endure a terrible brake squeal.
This squeaking sound warns you about a worn brake pad, reminding you to get them changed before you lose braking integrity and suffer complete brake failure.
How to fix:
Once you hear a brake squeal, it’s time to contact a mechanic and have your worn out brake pads changed. Sometimes a rotor is too far gone, along with your thinned brake pad, and you’ll have to replace it too.
The brake system in some modern cars has electronic wear indicators attached to the pad that trigger a warning light when they come into contact with the brake rotor surface. This adds a visual warning and allows you to have your worn brake pads replaced before you have to endure brake squeak.
5. A Stuck Caliper
If you get squealing or squeaky brakes even when you’re not applying the car brakes, you could possibly have stuck or frozen calipers. A stuck caliper in your disc brake can happen for several reasons, from issues with the caliper slides to the caliper piston.
How to fix:
Get hold of a mechanic to have the issue sorted and end that brake squeaking before your brakes lock up completely.
6. High Metal Content in Brake Pads
Not all disc brake pads are created equal.
High-performance carbon metallic brake pads are prone to squeaking. Brake pads with a high content of organic brake material such as resin, rubber, and Kevlar squeak the least against the braking surface.
Semi metallic brake pads have a high metal content pressed into the brake pad material. These metal pieces will continue to scrape against your brake disc, creating a louder ride. Bear in mind that semi metallic brake pads are often used in high-performance applications.
How to fix:
Semi metallic brake pads are probably not the best option when looking for replacement brake pads for your day-to-day driving. Opt for premium disc brake pads (like ceramic brake pads) that generate less noise and have great stopping power as well.
7. Debris in the Braking System
Brake dust isn’t the only friction material that causes squeaking. Sand, mud, or metal debris may be lodged in the pad or brake rotor, scraping the pad. The more time you spend driving offroad, the more likely there’ll be debris on the braking surface — which means you’ll have more brake noise.
How to fix:
The easiest way to address squeak is to apply a brake cleaner or sand down the brake pad surface.
But if the brake cleaner doesn’t fix the problem, don’t hesitate to consult a knowledgeable mechanic and have them take a look at your braking system. They’ll determine if the brake squeaking results from debris when you apply the brake lever or if there’s another cause.
8. Your Personal Braking Style
If you repeatedly press the brake lever or ride your brakes, the heat generated will cause the surface of your brake pads to glaze. Another cause could be brake caliper failure. When your brake caliper breaks, your brake pads rub against the rotor, glazing your brake pads.
Either way, glazed brake pads no longer generate the friction needed to stop when you hit the brake pedal. They’re vulnerable to cracks or fractures, and they make a squeaking noise. As a result, you’ll need to get new brake pads.
How to fix:
You can check for signs of glazing by running your finger along the surface of your brake pad and trying to feel for a smooth and glassy finish. If your brake pads are glazed, schedule a brake repair service to get new brake pads as soon as possible.
Most importantly, if glazing or brake squeaking is a constant problem, you’ll need to rethink your braking style, or you’ll soon need new brakes.
Final Thoughts
All brakes squeal from time to time. The heat generated by braking or driving through a puddle may cause your brakes to squeal. But that’s perfectly normal.
You should be concerned with noisy brakes if the squeaking is consistent or intense. For example, it might be time for new brakes if they don’t have the same stopping power they used to.
For a thorough brake repair, no one does it better than the professionals.
And that’s where AutoNation Mobile Service comes in.
Contact us, and our expert technicians will fix the brake system in your driveway!