Your car can make a variety of noises unexpectedly. When in good working order you should be aware of the sounds your car makes, and they should be fairly limited as well. Understanding the sounds that your engine makes when it's working properly, the sound that your starter makes as it gets the car going, and so on are all things that you need to be familiar with. That way, when something does go wrong, you'll be able to tell right away because of the change in sound.
When your brakes are not working properly, they are one of the most noticeable parts of your vehicle in terms of the sound that they make. When your brakes start making a noticeable, high-pitched squeaking or squealing sound when you use them even at a slow speed that’s a clear sign something is wrong and needs to be addressed.
What Causes Your Brakes to Squeak When You're Stopping Slow?
When it comes to noises from your brakes it's more normal for it to happen when they're under extreme stress. That's even what you would think of would cause brakes to squeal. If you hit the brakes suddenly with great force the idea that they might be making noise doesn't sound too hard to believe. So, when brakes start making noise when you're just gently tapping on them and you're driving at a slow speed it can strike you as extremely unusual and unexpected. This is especially true if the noise actually stops when you're braking normally at speed. There are several reasons that your brakes might be making that noise when you're just driving slowly, however.
The sound made by brakes is a high-frequency vibration. It's what happens when your brake pads rub against the rotating disc. That is how brakes are supposed to work after all. Friction is what causes your brakes to slow the wheels and stop them from moving.
The caliper clamps squeeze the brake pads when you put your foot on the brakes. The hydraulic pressure in your brake lines causes the reaction and the pads are meant to tightly grip the rotors slowing your car down. The friction is inevitable and, in fact, desirable. On the other hand, if you did something like tighten up the calipers to create more friction, you’d actually end up making more squeaking rather than last, so that's not the problem.
There is something called a shim between your brake caliper and the brake pads that is meant to absorb most of the vibration and prevent any significant noise. There's also lubrication in there that operates at high temperatures which also absorbs and ameliorates a lot of the vibrations.
Unfortunately, there are outside factors that can lead to increased vibration in your brakes for increased noise. Even something as simple as high temperature and humidity can affect how your brakes work.
You may notice that the brakes squeak after rain or on a particularly humid morning when you start going out for a drive. That's the result of moisture in your brake assembly, around the brake pad and rotor. This is more annoying than a serious problem that you need to worry about. It's inevitable that some water will get in there at some point in time, and if it's not affecting the performance of your brakes, only the sound they make, it may not be something you need to worry about. If it happens with remarkable regularity and even on mornings when it's not damp, then you may have a different problem you need to address.
When it does happen it's actually causing a very thin layer of rust to form on the rotor. When you apply the brakes, the thin layer of rust will be scraped off as a powdered rusty debris. This is what ends up being the source of the squeal in your brakes.
Drum Brake Lubrication
The shoe to brake backing plate may need lubrication if you hear a squeak from the back brakes when you put pressure on the pedal. When they're not properly lubricated the shoe will begin the scraping against the backing plate when you apply the brakes, creating a squealing noise. Lubrication prevents the buildup of rust and metal on metal squealing that can cause that annoying sound. You can prevent this by applying a high-temperature anti-seize compound or something called Moly Paste 60. The only thing to remember here is that it needs to be applied to the back of the brake pads and the brake pad/shoe contact points. You don't put it on the brake pad itself, as that would seriously inhibit your brake’s ability to work.
The substance that your brake pads are made of will also have an effect on the noise that your brakes produce when you apply them. Because brakes have to absorb a lot of friction, they need to be able to handle high heat over a long period of time. Asbestos was once the material of choice for this, but a specialist is carcinogenic and extremely dangerous to use.
When asbestos was phased out, a number of other materials came into play including things like ceramics, Kevlar, and various metal blends. Kevlar can be dusty which may lead to some squeaking in the brakes, but the various ceramics and metals used may also lead to sound such as hissing, grinding, and squealing. These are minor annoyances again, as they're not actually indicative of a problem with the brakes. Your brakes will still function perfectly normally when these sounds occur, it's just kind of annoying to deal with.
There are some lower quality brake pads, usually the aftermarket kind, that are made with a very high metal content. Most brake pads have a degree of metal in them, but the cheaper ones have a large quantity that can become damaging to your rotors overtime. As the metal embedded in the pad material presses against the rotors, you'll hear that squealing sound and it can potentially last for the entire life of the pad. That could be upwards of 30,000 miles to 40,000 miles. As you can imagine, that would be very annoying.
When you're looking for new brake pads you want to make sure you're focussing on ones that have more organic material in their construction. Kevlar, rubber, resin, fibre, and so on are all materials that brake pads have in their construction that is less damaging and less annoying in terms of making noises that you don't want to listen to.
If the problem is bad enough you could have your brakes recalibrated, and a mechanic could potentially take the entire assembly apart and try to alter the harmonics. That may be an extreme path to take, but if the problem is bad enough you may want to look into it.
Just as water can find its way into your brake assembly so you can foreign substances like dirt, dust, grease and so on. If that happens you may end up with a squealing or hissing sound when you apply your brakes as well. This is more likely to affect the performance of your brakes than something like water in there. Bad enough then your brakes may not work as effectively as normal, and that could endanger yourself and others as a result. If you're finding that your brakes are not only squealing but they're not responding the way they should be, your brake pedal is feeling spongy or it's taking you a long time to stop, you need to get them serviced as soon as you can.
Thinning Brake Pads
When your brake pads have worn down too much then you may hear the sound of your brake wear indicator rubbing up against the rotor. This sound is meant to specifically indicate that your pads are too thin and need to be changed. If this is the case, you’ll begin to notice the sound when you brake at speed as well as when you brake slowly. The sound will also sound a little different than a typical squeal or whine.
Cost of Repairing Squeaking Brakes
If the squealing of your brakes has become too annoying for you to bear, or you feel that it is in fact causing a decrease in overall brake performance, then you may need to get your brakes repaired. Even if your brakes aren't malfunctioning, the sound can be annoying enough to justify getting some new pads swapped in.
The cost of getting brake pads replaced will generally go per axle. So, you would normally replace either your front brakes at the same time or your back brakes at the same time. You could do them all, but that will double up for the price.
The average cost of replacing brake pads is around $150 to $300 per axle. This can vary greatly depending on the type of pads that you're using. You can head to AutoZone and see that brake pads can cost anywhere from $25 to $50 or more depending on the materials.
Can I Repair My Own Brakes?
As with any repair job you can definitely do your brakes at home if you want to. Changing your own brake pads, for instance, it's not a very difficult job at all if you're comfortable working on your own car’s repairs. The thing to remember here however is that there are more causes for squeaking in your brakes and just issues with the brake pads, as we mentioned.
If you want to change your brake pads, there are plenty of guides online that will show you how to get it done properly. Videos like this one can walk you through the process in great detail so you can see exactly what you need to know and make sure you're not missing any crucial steps.
You need to make sure you have a floor jack and jack stands to get this done, and you'll also need a break too as well. This is a tool that adjusts the brake caliper piston to the new brake pads and is important for ensuring that you have precisely fit brake pads when you swap to the new ones. The last thing you want is to have the pads installed but not adjusted correctly so that they don't actually clamp down on the rotor when you put your foot on the brakes. This is definitely one of the more unusual tools to use however, and most people don't have this in their toolbox if they don't spend a lot of time doing brakes.
Fortunately, you can pick up one of these tools on a site like Amazon for under $15. It's a good investment to make it if you plan to be doing your own car repairs.
Many drivers are intimidated by the idea of working on their own brakes because it's a scary proposition that you might do something wrong and the brakes are the last thing you want to fix incorrectly. For that reason, there is definitely no harm and just taking your car to a mechanic to get this looked at rather than trying it on your own. There are a number of different things you need to take into account when fixing your brakes so if you're not 100% comfortable doing that job then it's best to leave it to a professional but you can count on to make sure nothing has gone wrong.
Can I Clean My Own Rotors?
If the problem is that there is debris, rust, or moisture buildup that you need to remove then you should be able to get this cleaned off on your own without going into a mechanic to get the job done. There are also videos that can detail this process for you so you can go through step-by-step and remove any rust or debris build-up to extend the life of your brakes and rotors and prevent your brakes from squealing even when you're trying to stop at a slow speed.
This process can be fairly simple, and you only need to use hot, soapy water to get the job done effectively. It's well worth doing on your own if you feel up to it, as you'll save yourself a lot of time and money.
The Bottom Line
Squeaking brakes is one of the most annoying things that can happen in your vehicle, especially when it keeps happening when you're driving at a slow speed. fortunately, it doesn't always mean that there's a problem with your brakes. If you're concerned, you can check out some of the things with detail as potential causes and if you need to then replacing the pads or rotors could end up fixing the problem for you.
If you ever concerned about the safety of your breaks, make sure you get them checked out immediately as this is definitely one system you never want to leave to chance.