Why Are My Brakes Making Noise?

Do you hate when you hear that squeaking sound everytime you press your brakes? Even on a brand new disc, you may still hear that sound. So, why are your brakes making noise?
The reasons why your brakes are making noises is because your brakes are worn out, contaminated with dirt and rust, not lubricated properly or your dust shield is bent against the rotor.
Let me explain more why your brakes are making noises and how to fix it.

Top 5 Reasons Why Your Brakes Make Noise And How To Fix It

I will tell 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. 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 the brake rotor that causes friction and slows the car down. The space between the caliper and brake pads is very small. There’s a lot of pressure and there’s a lot of friction. 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.

1. Worn Out

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. A brake pad should have the backing plate and then your braking material on top. If your brake pads are worn all the way to the rivets, that’s pretty bad and this could be the reason for the noise. The only way to know that your brake pad is wearing down is to take the wheels off and inspect them. On quality brake pads, you have something called wear indicators. Wear indicators are these metal clips that stick out past the backing plate so as your brakes wear down to about two to three millimeters, it will start screeching against the brake rotor and it will let you know that the brake pad is worn out. So, as you’re driving along and you apply the brakes the wear indicator contacts the rotor surface and makes a squeaking noise, and that squeak will let you know that these brake pads are dangerously low and they need to be replaced. Although the pads wear out a lot faster the rotor also starts to lose material.  When a rotor wears down, it wears down in the middle smooth part. It doesn’t wear away the sides which could 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 can make contact with the rust. If that’s your problem, sometimes you could 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 brake noise and prevent your
rotors from wearing out.

2. Contamination

The second common cause of brake noise could be seen without taking off the wheels, and that is dirty or contaminated brake pads and rotors. Your brick rotors have tons of grooves in there. 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. 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. A little rust 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. So that’s contamination on the rotor surface, but how about the brake pad surface. So before you go out and buy brand new brake pads, sometimes your brake pads have a lot of life left on them. One thing that you could do, you should grab some sandpaper and just sand down the surface to remove the contaminants.
Next source of contamination is 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 a cleaner or you could use plain old soapy water. I prefer using brake cleaner when cleaning the rotors. So, just spray it on there, then wipe it down with the clean towel. You don’t want to forget to clean the other side as well. Since we’re talking about cleaning with brake cleaner, one thing I want to talk about is getting brake clean on your pad surface. You don’t want to use brake cleaner on your brake pad surface. It could break down the material of the brake pad, it could cause swelling. The other thing is a lot of brake pads are painted and brake cleaner damages the painted surface which could cause rust. Some brake pads use this rubber backing plate, and the brake cleaner could eat away at the rubber backing plate.

3. Brake Hardware

The third reason and probably one of the most overlooked parts to changing out your brakes is replacing the brake hardware. Brake hardware are any of the components that are in or around the brake caliper and brake pads. What the brake hardware does is, it allows the brake pad to slide smoothly and quietly in the brake caliper, and as your brake pads wear out your brake hardware wears out and it becomes difficult for your brakes to slide smoothly in the brake hardware. That friction could create squeaks and also could 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. When you press on the brakes, the wheel cylinder pushes the shoes outwards 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. There isn’t too much space between the shoes and the drum so 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.

4. Lubrication

The fourth reason why your brakes make noise is because they’re not lubricated. So, for brake lubrication, I am using two different lubricants to lubricate two different things. I am using the copper NTC’s to lubricate any contact points between the brake pads and brake caliper, and the silicon paste to grease the caliper guide pins which definitely need lubrication. Whenever I replace brakes I like using copper anti-seize. Every time you press on the brakes, the braking system is under a lot of pressure. So the first area of lubrication is at the brake caliper bracket right where the brake pad and guide meets up. It makes sense they have some type of lubrication so you don’t have metal to metal contact with no lubricant. 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. That’s everything you need to lubricate. Next, on the drum brake backing plate, there are six contact points, three on each side that you want to add anti-seize to. And just like the disc brakes, you don’t want to use a lot of anti-seize, especially on the 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 the contact points.
Next, use the silicon paste to lubricate the guide pins. It’s important that these guide pins are lubricated because the caliper should slide back and forth easily. So all you do is loosen the guide pin bolt, slide the caliper out of the way and pull the guide pin out. 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 that will cause squeaking as it moves back and forth. Add a coat of silicone paste and slide the guide pin
right back in. Why you use silicone paste is because it could withstand the heat of the brakes and it won’t damage the rubber dust boots like a petroleum-based grease will.

5. Dust Shield

The last reason on why your brakes make noise isn’t something that many people think of but is surprisingly common and that is brake noise created by the dust shield. The dust shield does exactly what it says. It’s the thin metal plate that’s 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 its thin bendable metal. It can easily bend against the rotor and make scrapping noise.

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Hi there. I am a certified Automotive Service Excellence (ASE) mechanic since 2018 and a car detailer for 10 years.

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