Why Do My New Brakes Squeal?

Have you recently replaced your brakes only to find they’re making an unusual squeaking sound?

There’s no need to fret, as this happens quite frequently.

If you’re searching the internet for answers to “why do my new brakes make noise?” then you’ve arrived at the right spot!

One of the most common reasons that new brakes squeal is that there’s moisture on the rotors. A thin layer of rust will develop on the surface when they get wet. When the pads come into contact with the rotors, these particles get embedded into them, creating a squealing sound.

Thankfully, in this brief and informative guide, I cover everything you need to know about squealing brakes.

We will first review the difference between the two main types of braking systems – drum and disc.

Afterward, we will examine the most common reasons they make noise and provide a few simple tips to help quiet them down.

Let’s dive right into it!

Drum vs. Disc: What Is The Difference?

Drum

This system gets its name due to it being housed in a cast-iron drum-like casing. When you press the brake pedal of a vehicle equipped with drum brakes, it sends hydraulic fluid into what’s known as a wheel cylinder.

Inside this cylinder are two pistons that, when triggered, push outwards.

As this happens, they press against what’s called a brake shoe, which consists of a curved piece of metal with a friction material attached to one side. When the shoes and the interior of the drum meet, it generates friction. This decelerates the rotation and, therefore, the vehicle.

Drum brakes have largely been phased out on contemporary cars.

However, some entry-level models still use them on the rear because they are less expensive to produce. The problem with drum brakes is that they’re more intricate, which makes them more susceptible to maintenance. They also generate more heat, causing them to deteriorate faster.

Disc

A disc braking system is similar to a drum in that pressing the brake pedal sends hydraulic fluid to a piston, causing it to press against the caliper. A caliper is a clamp-like device that fits around a portion of the rotor and houses the brake pads, which are equivalent to shoes.

Then there is the rotor, which is a metallic disc that’s affixed to the wheel. As the wheel turns, so too does the rotor. When the pads press against the rotor, it creates friction, which slows the rotation.

This interaction generates a lot of heat, so the rotors have minuscule holes drilled into them, allowing the heat to dissipate.

This system is less complex and has fewer moving parts, which makes it easier to maintain, yet, more expensive to produce. Most newer cars have a disc braking system due to their added stopping power.

Now that you better understand the two primary types of braking systems. Let’s look at a few of the most common reasons they might squeal.

Common Reasons Your New Brakes Squeal – And How To Quiet Them Down

Note: Before performing any repairs, you’ll first want to determine where the squeal is originating. To do this, roll the windows down and brake, listening for which wheel is producing the sound.

Wet Brake Rotors

As mentioned earlier, damp rotors are one of the primary causes of squealing brakes, regardless of whether they’re new or old.

When water remains on your brakes, it causes corrosion to form. Then, when you use your brakes, the rust breaks into minuscule pieces.

These particles then become embedded into the brake pads, and when they press against the rotor, it creates a shrill sound. Thankfully, this does not last very long, and after a few hard stops, it should disappear. If not, the issue might be more severe.

This is not really something you can repair since there is no way to avoid every puddle and not driving on days it’s precipitating isn’t practical.

Lack Of Lubrication

This specific cause of squealing brakes only applies to cars equipped with a drum braking system and can happen on new or old brakes as the pistons press the shoes outwards against the drum.

If there’s not enough lubrication, they may let out a piercing sound as they scrape against the backing plate.

To fix this, remove the drum and apply a minuscule amount of brake lubricant to the backing plate where the piston meets the shoes. You can usually tell where the issue is by looking for signs of scraping where the bare metal is visible.

Worn Or Thinning Brake Pads

While this doesn’t really pertain to new brakes, it can still happen if you’ve replaced a caliper or rotor without swapping out your pads.

Most brake pads last between 25,000 to 65,000 miles, depending on your driving habits. 

Thankfully, manufacturers design brake pads with metal indicator tabs near the base. When the pads become too worn or slender, they rub against the rotor, emitting a piercing sound.

You should substitute your pads promptly when this happens, or you’ll risk having reduced stopping power.

Depending on the quality of the pad, they should cost anywhere between $100 to $200 each at a shop (including labor).

If you know how to replace them, expect to pay between $50 and $150 for each pad. If you don’t, check out the video below for thorough instructions.

Glazed Brake Rotors

As rotors age, they develop flaws, and if you get new pads, they won’t match the shape of these imperfections, resulting in a squeal. Thankfully, rotors usually last between 30,000 to 70,000 miles.

If your brakes haven’t yet reached this number, you will probably only need to resurface them rather than replace them.

Thankfully, many quick-lube-style shops only charge $10-$15 to resurface (or turn) rotors, which is a lot less costly than replacement, which usually runs around $500 or more.

You can also do this yourself by removing the wheel and polishing the surface of the rotor with 1,500-grade sandpaper.

Brake Pads High In Metal Content

Another reason your new brakes might squeal is if the replacement pads are elevated in metal content. Most brake pads contain a blend of various metals, including iron, steel, copper, and graphite. Depending on the ratios, they might squeal as they rub against the rotor.

There are options made from organic materials, such as glass, rubber, and heat-resistant resins. Though, these often lack the same halting power as metallic pads.

The other option (arguably the best) is ceramic brake pads, which combine copper fibers and ceramic. These are the quietest and most enduring options but also the costliest.

If you can’t handle the squeal, you might consider swapping out your brake pads for ones with less metallic material in them.

Don’t Let Squealing Get You Down – Instead, Get Rid Of The Sound

Replacing your brake pads might be the solution you need.

However, if it’s not, don’t squander your money. Instead, if a high-pitched sound is driving you crazy, consider the other options first, most of which are free or only require that you spend a minimal amount.