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Hey guys, Chris fix here, and today I'm going to show you the top five reasons why your brakes make noise. Now, this could be anything from a squeak to a grind, and it could be continuous or only when you press on the brakes like this. Since this Jag is making noise, it's a perfect time to show you not only the reasons why your brakes might make noise but also how you fix it so it's nice and quiet, because I don't know about you, but I hate when brakes squeak. Now, this video is easily one of the most requested videos from you guys, so much so that I've been saving up all these brake components from all the different brake jobs that I do, that way I could show you the many reasons why brakes make noise. I also want to thank Advanced Auto Parts for supporting this video and sending over a bunch of new brake parts, that way I could compare the old brake parts to the new ones and show you the difference. Now with that said, let's jump right into it and begin.
The first thing we need to do is understand what brake noise is, and it's pretty simple: it's vibration coming from one of the brake components when you press on the brake. This caliper pushes the brake pads and squeezes this brake rotor, which causes friction and slows the car down. Let me show you an example on the rear brakes. This is pretty cool, because this is something you don't normally get to see, your brakes actually working. I'm going about 20 mph, and then when I hit the brakes, you can see the brake caliper squeeze the brake pad against the brake rotor. Then when you let go of the brakes, the brake pad moves out very slightly, so it just comes off the brake rotor. The clearance here is really tight, less than a millimeter, and in this case you can see there's a little bit of wobble in my brake rotor, and you can hear a light rhythmic scraping noise. That's because this rear brake rotor is warped, probably from all the track days and grabbing the e-brake for drifting. Since there are tight tolerances, there's a lot of pressure and a lot of friction, and even the smallest things could cause brake noise. This noise could happen with brand new brakes or with brakes that you've been using for a while. I'm going to cover the source of the noise for these five common problems, and I'm going to show you how to fix it so your brakes are nice and quiet.
So let's begin with number one. The first, and probably most important, reason why your brakes make noise is because they're worn out. This could be worn out brake pads, worn out brake rotors, or both, but let's cover brake pads first. This is a really worn down brake pad. Just to give you a comparison, here's a brand new brake pad, and if we look, here's what it should look like: you have the backing plate here, and then you have your braking material on top. If we look at the worn down brake pad, it's just a backing plate. This pad was worn down all the way to the rivets, and that's pretty bad. On a brake pad like this, the only way you know this brake pad is wearing down is to take the wheels off and inspect them. But on quality brake pads, you have something called wear indicators. Wear indicators are these metal clips that stick out past the backing plate. As your brakes wear down to about 2 to 3 mm, this will start screeching against the brake rotor, and it'll let you know that the brake pad is worn out. This brake pad is a perfect example of how wear indicators work. You can see the wear indicator is sticking out past the brake pad material, so as you're driving along and you apply the brakes, the wear indicator contacts the rotor surface and makes a squeaking noise. That squeak will let you know that these brake pads are dangerously low and need to be replaced before you get down to the backing plate like this brake pad. So a wear indicator is definitely a good thing to look for when you're buying brake pads.
Worn out brake pads can make noise, but so can worn out brake rotors. Every time you hit the brakes, the brake pad comes in contact with the rotor surface, and the brake pad starts to wear down. Although the pads wear out a lot faster, the rotor also starts to lose material. An extreme example of a brake rotor getting worn out is this right here. Whoever drove this car wore it down to the cooling vanes, which is pretty bad, and I could only imagine the kind of noise that this brake rotor made when they pressed on the brakes. When a rotor wears down, it wears down in the middle at this smooth part, but it doesn't wear away the sides, which can create an edge over time. This edge could rust, and since it's so close to the pad, if the pad shifts at all, it could make contact with the rust ridge and cause brake noise. If that's your problem, sometimes you can fix the noise with just a little bit of sandpaper. All you have to do is sand the edge of the rotor where the rust is building up, and then when you use your brakes, there's no more rust for the brake pad to contact, so you won't get your brake noise. To prevent your rotors from wearing out like that, there is a minimum thickness for every rotor. For example, this Jaguar rotor, brand new, is 24 mm thick, and the minimum thickness, meaning you need to replace it if it's thinner, is 22 mm. All you have to do is measure it with a digital caliper, and this one is 23.4 mm thick, so we're within our minimum thickness. When you're measuring, make sure you're measuring down here on the flat surface and not up on the rust ridge. If your brake rotors are too thin, you're going to have to replace them. In this case, if I wanted to, I could get them resurfaced, but most of the time I'm replacing rotors anyway, because by the time you get them resurfaced, it's a few more bucks just to buy brand new ones.
Worn out brakes are an obvious reason for brake noise, but these next examples are other common causes of brake noise that might not be as obvious. The second common cause of brake noise could be seen right down here with my Jaguar, and that is dirty or contaminated brake pads and rotors. Looking at these brake rotors, you can see there's tons of grooves in here. These grooves are caused by dirt getting in between the pad and the rotor, and then when you press on the brake pads, it digs into the rotor. That could be road salt, it could be dirt from going off-roading, maybe you drove through a muddy puddle. Basically, anything small enough to get in between the brake rotor and brake pad surface can cause grooves. The grooves could also be caused by poor quality brake pads, which have bits of hard brake material scattered in them, which could score the rotor surface, especially when the rotor heats up. Another type of contamination that can make your brakes squeak is rusty rotors. Depending on where you live, rust could be an issue, and brake rotors rust really easily. Check this out: I sprayed a rotor with water, and in a matter of minutes you can actually see the water droplets evaporating and rust forming on the rotor. Now, a little rust like this isn't a problem at all, but if you let your car sit for a long time without driving it, the rust could be bad enough, like with this rotor, that you need to get the rotor turned or get a new one.
That's contamination on the rotor surface, but how about the brake pad surface? Before you go out and buy brand new brake pads, because sometimes your brake pads have a lot of life left on them, one thing you could do is grab some sandpaper. In this case I have 180 grit, but anything from 100 to 200 grit will work. Just sand down the surface to remove the contaminants. That's how you remove the top layer of contamination, but in this case our pad is so grooved that it's no good. Same thing with our rotor, which is grooved, so we need to replace that. That brings me to my next source of contamination, and that's brand new brake rotors. To prevent your brand new brake rotors from getting rusty in the packaging, manufacturers use an oil coating, which needs to be removed. To remove this contamination, you could use brake cleaner, or you could use plain old soapy water. All this is is dish soap and water. I prefer using brake cleaner when cleaning the rotors. Just spray it on there, then wipe it down with a clean towel. Check out all the oil we removed. You definitely don't want that on your brakes, and you don't want to forget to clean the other side as well.
Since we're talking about cleaning with brake cleaner, I want to talk about getting brake cleaner on your pad surface. Can brake cleaner damage the brake pad surface if you get it on there? The answer is yes. You don't want to use brake cleaner on your brake pad surface. It could break down the material of the brake pad, and it could cause swelling. Also, a lot of brake pads are painted, and brake cleaner damages the painted surface, which could cause rusting. Some brake pads use a rubber backing plate, and brake cleaner could eat away at the rubber backing plate. That being said, if you get a little bit of brake cleaner on there, it's not the end of the world. You just don't want to soak it and saturate it in brake cleaner. So if you do get some brake cleaner on here, or if you get some oils on here, one thing you could use is just plain old dish soap and water. Spray it down and wipe it off.
So brake pad and rotor contamination is the second reason brakes make noise. Looking at these brakes, they definitely have to be replaced, both pads and rotors. I just noticed something: there's no brake hardware, which brings me to my next reason why your brakes might make noise.
The third reason, and probably one of the most overlooked parts of changing out your brakes, is replacing the brake hardware. Brake hardware is any of these components that are in or around the brake caliper and brake pads. For example, we have a brake caliper here, and here's our brake hardware, and it just clicks right in like that. What the brake hardware does is allow the brake pad to slide smoothly and quietly in the brake caliper. As your brake pads wear out, your brake hardware wears out, and it becomes difficult for your brake pad to slide smoothly in the brake hardware. That friction can create squeaks, and it can also create excessive brake wear. That's for disc brakes, but there's also brake hardware for drum brakes. Drum brake hardware is made up of springs, which are very important. Let me show you why. I cut apart this drum so you could see how everything works. When you press on the brakes, the wheel cylinder pushes the shoes outward, which then rubs against the drum, creating friction and slowing the vehicle down. When you let go of the brakes, the springs pull the shoes off the drums, so there's no more friction, and there isn't too much space between the shoes and the drum. The springs have to be in good shape and working properly to ensure that the shoes don't continue to rub against the drum with your foot off the brake. You can really see the importance of getting new brake hardware, which is why when you get new brakes, make sure they come with brake hardware. If they don't, it's inexpensive enough and worth every penny.
With that being said, some cars don't use the typical brake hardware. For example, on my Jag, when you get new brake pads, the only brake hardware they make for this car are the guide pin bolts. For brakes like this, all you have to do is get a metal wire brush, and where your brake pads make contact with the caliper, you want to clean out this area really well so it's rust free and nice and smooth. If you have a rotary tool, you could get a wire brush attachment, and it makes cleaning this up even faster. All you're trying to do is get the surface smooth and rust free so the brake pads can slide freely, just like that. So not using brake hardware is the third reason why your brakes make noise.
Since I need new rotors, I want to share a top tip with you: anytime you replace rotors, make sure you use a wire brush to smooth down the hub surface so it's not rusty. Rust could cause the rotor to sit unevenly and cause brake rotor runout, which could look like a warped rotor and give you a rhythmic brake noise like this. You also could feel this because the brakes might pulsate. So get that hub surface nice and smooth, then apply a thin layer of anti-seize to prevent future rust and make it easier to get the brake rotor off for your next brake job.
Speaking of anti-seize, the fourth reason why your brakes make noise is because they're not lubricated. We're going to be using two different lubricants to lubricate two different things. We're going to use the copper anti-seize to lubricate any contact points between the brake pads and brake caliper, and then we're going to use silicone paste to grease the caliper guide pins, which definitely need lubrication. These things are stiff. First, let's talk about the anti-seize lubricant. Whenever I replace brakes, I like using copper anti-seize compared to graphite anti-seize. They both will work, but copper anti-seize is better for brakes, and here's why. Every time you press on the brakes, the braking system is under a lot of pressure. To simulate graphite under a lot of pressure, I have graphite from a pencil, and what I'm going to do is put pressure on it. It's not even that much pressure, and you can see what happens: the graphite breaks down into smaller pieces. That's good if you're trying to lubricate the threads on a bolt, and it will work for the brakes, but it's not as good as copper anti-seize. To simulate copper anti-seize under pressure, I have a thin copper pipe. If you take a look, the copper just bent. It didn't break up into little pieces, because copper is more malleable compared to graphite, which isn't. Copper-based anti-seize holds up better under pressure, while graphite-based anti-seize continues to break down. That's why, if you can, you want to use copper-based anti-seize when lubricating your brakes.
To show you how to properly lubricate disc brakes, we're going to use my Mustang as an example. The first area of lubrication is right here at the brake caliper bracket, right where the brake pad and guide meet up. Here and down here, we want to add some anti-seize. Be careful, just add a little bit right down here and right up here. It makes sense to have some type of lubrication here so you don't have metal-to-metal contact with no lubricant, because this does have to slide back and forth as the brakes get used. Then on the other side of the caliper, you have the identical spots where the brake pads sit, and you also want to lubricate those. It's also important to lubricate the brake hardware, so just get a little copper anti-seize and lubricate the top of the brake hardware. The last place to add a thin layer of anti-seize is on the back of the brake pad, which helps prevent squeaks. That's everything you need to lubricate.
Next, I'm going to show you how to lubricate drum brakes using my truck as an example. On the drum brake backing plate, there are six contact points, three on each side, that you want to add anti-seize to. Just like disc brakes, you don't want to use a lot of anti-seize, especially on drum-style brakes, because these get very dusty, and any lubrication you use will collect dust. You just want a very thin layer on each of those contact points, just like that.
Back at the Jaguar brakes, I lubricated the contact points with anti-seize, and now I'm going to show you how to use silicone paste to lubricate the guide pins. It's important that these guide pins are lubricated because this caliper should slide back and forth easily, and this one has a little bit of resistance, because these guide pins need to be lubricated. All you do is loosen the guide pin bolt, slide the caliper out of the way, and pull the guide pin out. Then clean all the old lubricant off with a paper towel and do a quick inspection to make sure the guide pin is smooth and not rusty, because rust will cause squeaking as it moves back and forth. This looks nice and smooth, so add a coat of silicone paste and slide that guide pin right back in. Now look how easily this moves. We can add our guide pin bolt and tighten it down, then make sure you do the bottom guide pin as well. The reason you use silicone paste is that it can withstand the heat of the brakes, and it won't damage the rubber dust boots like a petroleum-based grease will. So there we go, that's the fourth reason why your brakes make noise and how to prevent it with lubrication.
Our last reason why your brakes make noise isn't something many people think of, but it is surprisingly common, and that is brake noise created by the dust shield. The dust shield does exactly what it says: it's a thin metal plate behind the brake rotor, and it prevents brake dust from getting all over the suspension components. It also helps prevent water, dirt, and debris from getting all over the brakes. The problem with the dust shield is that it's thin, bendable metal, so a lot of times friends, neighbors, and family come to me with a scraping noise, and when I take the brakes apart, the dust shield is rusted or bent and scraping against the brake rotor. Although it's such a simple problem, it's definitely something to keep in mind, and it's the fifth reason why your brakes could be making noise.
If you have any questions about your brake noise specifically, feel free to leave a comment below. And if you've had experience yourself with brake noise for a reason I didn't cover, make sure you share that in the comments below, because that would be a great contribution, and I'm sure it'll help people out. Hopefully the video is helpful. If it was, remember to give it a thumbs up, and if you're not a subscriber, consider subscribing.