Few things can be as frustrating for a driver than the sound of squealing brakes when you're trying to stop your vehicle. And when you know it's your brakes making the sound it can also be unnerving because your initial fear is that your brakes are failing and you're putting yourself and others at risk of having an accident.
Brakes can be prone to making a very high-pitched squealing or squeaking sound, and this is going to be present even at extremely slow speeds. Anytime you apply the brake and you hear this noise your immediate fear is that your brakes are worn down, you're not getting the friction needed to stop your car, and you may end up running through an intersection or crashing into the car in front of you when you need your brakes the most.
Even when your brakes seem to be working fine, the sound can be extremely frustrating and distracting. If it happens continually and it's particularly loud, it can really start to grate on your nerves. So let's take a look at why exactly your brakes are making the Sounds in the first place, and what you can do about it.
What Do Brakes Squeak?
Brakes work thanks to friction. When you put your foot on the brake pedal, hydraulic liquid is forced down on a piston in your brake caliper. This causes the calipers to squeeze and the brake pad is pressed against the rotor of your brake. That creates friction in the form of a very high frequency vibration. Just think of how fast the wheels on your vehicle are turning when you're driving at speed and then you put your foot on the brakes and those small pads have to apply enough pressure to make your car stop.
Obviously, friction is the intended goal here. Without friction you don't have brakes so it's not as if it's a problem when you create this high-frequency vibration. The problem is when it becomes audible it may make you think there is a problem. But it doesn't necessarily mean that there is a problem with your brakes, nor does it mean that you could tweak them to fix it necessarily. For instance, if you tried to tighten your calipers to force the brake pads more snugly against the rotor you would probably end up creating more noise rather than less.
When your brakes are working normally there is a shim that is placed between the caliper and the pad that is used to absorb the vibration. Your brakes also contain a certain amount of lubrication that help dissipate the vibrations to reduce noise. Sometimes outside factors can affect the ability of the shim to prevent this noise but it's not necessarily indicative of a malfunction in your brakes. For instance, high humidity may affect the noises produced by your brakes. As well some contamination from road dust or bits of corrosion that have worn off could also contribute to this. They don't necessarily decrease the effectiveness of your brakes, but they will make them noticeable while you're driving. Let's get a little more in-depth into what causes your brakes to make noise.
Drum Lubrication: You have something called the shoe and a brake backing plate in your brakes. If you’re hearing squeaking from your back brakes when you are applying pressure to the pedal, you may need some lubrication in there to prevent the problem. When lubrication dries up or gets contaminated the shoe begins scraping against the backing plate and that creates a noticeable sound in your car. Proper lubrication here, just like anywhere else in your car, is going to prevent corrosion as well as that metal on metal grating that not only produces an annoying sound but can reduce effectiveness over time as well.
The thing you want to do is make sure you're using the right lubricant because not all lubricants are created equal, and definitely not all lubricants are made for brakes. You need to use something like Moly Paste 60 or any high temperature anti-seize compound. This would go on the back of the brake pads on your rear brakes but not on the brake pad itself. Your brake pads should not have lubricant on them because that will only reduce their effectiveness and not improve it.
Moisture: Like we said, high humidity can have an effect on your brake’s ability to work without making sound. If you drive you through some puddles after serious rain, or you just live in a humid climate, the moisture is going to make its way into your brake assembly and in particular around the brake pads and rotors. When this happens, it is definitely annoying, but it shouldn't be too much cause for concern. Water is an inevitable part of driving; you can't really avoid it. Some is going to get in there and your car has been designed to handle that as long as it's not too extreme. If it happens all the time, then that's something you need to worry about but typically this shouldn't be an everyday kind of problem.
Basically, the issue here is that moisture has caused a very fine layer of corrosion to form on the rotor itself. And as you brake, that layer of rust is being scraped off and the powder debris is grating against your brakes as a result when you use them. It should wear off on its own fairly quickly and the squeaking should stop as a result.
Contamination: Similar to the way water can affect your brakes, debris, grit, dust and dirt can make their way into your brakes as well. If they get badly contaminated this can also contribute to the squealing sound that you hear when you try to brake. When this happens not only will you have the sound, but you also run the risk of your brakes not working properly either because there is a layer of contamination between the pad and the rotor itself. This could potentially diminish your ability to brake on time and could lead to accidents.
Bad Brake Pads: When your brake pads wear down enough you'll start hearing a squealing sound every time that you put your foot on the brakes. This is intentional because your brake pads have wear indicators inside of them that let you know the pad material has worn down so much that they need to be replaced. The squealing sound you're hearing in this case is actually a warning sound that you need to have it replaced.
Material: What your brakes are made of has a substantial effect on the sound that they produce when you use them as well. Old timey brakes used to be made of asbestos because it's incredibly good at absorbing heat. However, as you may know, asbestos is also highly carcinogenic and therefore not safe to have around. Since that time other materials including Kevlar have been used to make brake pads. Kevlar can be very dusty however and that can lead to squeaking in your brakes when you use it because, just like the layer of corrosion that can be caused by excessive moisture, Kevlar will leave a layer of dust between the pad of the rotor as well. This won't affect the overall ability of your brakes to work, but it can be annoying because it will continue for quite a long time.
Brakes that have a high metal content are also more prone to squealing when you use them. These are usually cheaper aftermarket brakes however and the metal that's embedded in the pads will press against the rotors as they wear down. This will be a constant thing until the brakes get replaced, and they could last upwards of 40,000 miles making the sound continually.
How Do You Stop Your Brakes from Squeaking?
When it comes to preventing your brakes from squeaking it really depends on why it’s happening in the first place. As we’ve seen there can be a number of issues that contribute to this problem. If it is simply a matter of dust and debris, you could actually be able to clean them yourself in a fairly simple process at home. Just a little bit of soapy water will do it and you definitely don't need to go to a mechanic. There are helpful videos that can show you just what to do if you're interested.
If it's a matter of getting your brake pads replaced, you'll probably want to head to your mechanic to get this job done unless you're comfortable doing this kind of home repair on your car by yourself.
Will WD-40 Stop Your Brakes from Squeaking?
Around the house you may be tempted to use WD-40 to fix any kind of squeaky hinges that you have. It's a fairly decent lubricant when you have rusty or stiff metal that you are dealing with in a home repair situation. Some people will recommend that when your brakes are squeaking that you could use it to lubricate them and end the annoying sound. This is never a good idea.
To be clear, do not under any circumstances spray WD-40 on your brakes to try to stop them from squeaking.
WD-40 is not technically even a lubricant in the traditional sense. WD-40 stands for a water dispersant and the 40 refers to the number of the formula. It is meant to disperse water away from metal, not to lubricate parts like brakes. In fact, it's possible that if you were to spray too much WD-40 on your brakes you would find the pads unable to create friction and you would be unable to slow and stop your car in a timely manner. This could lead to a serious accident. So again, don't use WD-40 to stop your brakes from squeaking. Use it on the hinges of a screen door maybe, but that's it.
Cost of Repairing Squeaky Brakes
The cost of repairing squeaking brakes depends on a number of factors. You may want to simply avoid the repair if your brakes aren't actually suffering as a result. However, if you're afraid that they're not working properly any longer or the sound is too annoying then you may want to have new brake pads installed so that you don't have to endure the annoying noises any longer.
Getting brake pads replaced is a per axle job for the most part. That means you don't necessarily need to have all four done at the same time, you can do front or back. Since your brakes are probably only squeaking in the front or the back rather than all four, this will make it a more economical option.
On a per axle basis, you're looking at somewhere between $150 and $300 to get your brakes fixed. Obviously, this is going to depend on the mechanic you take it to as well as the brake pads you choose. Brake pads can start as low as $25, and get up to $50 or even $100 depending on the kind that you're going to buy.
Just remember if you're going to do front brakes and back brakes then you're doubling up on that price and could end up paying between $300 and $600 to do your full car.
The Bottom Line
Your brakes can end up squeaking for several reasons as we've seen and how you deal with it really depends on why this happened in the first place. You do need to determine whether or not it's a serious issue that's causing your brakes to squeak, or just an inconvenience. If it's something that affects the performance of your brakes then you're going to want to get it fixed as soon as you can. Otherwise, this may just be an issue that you have to deal with or you can swap out the brake pads for something more tolerable but it will certainly cost you more than trying to live with annoying brakes. It really is up to you, but make sure you understand one way or the other what's happening. You never want to take a risk when it comes to your brakes and your safety.