Brakes Squeak When Stopping Slow: 5 Potential Causes

If your brakes start squeaking when you’re coming to a stop, it’s a sign there could be an issue. Squeaky brakes while braking slowly can indicate your brake pads are worn down and need replacement.

Or there may be a buildup of brake dust and debris causing the noise. Whatever the cause, squeaky brakes shouldn’t be ignored. Continue reading to learn the common reasons for brake squeak at low speeds and what you can do about it.

So, why do brakes squeak when stopping slow? Brake dust buildup and moisture cause brakes to squeak, especially at slow speeds. Rust forms from condensation, leading to squeaking when brakes applied slowly. Worn brake pads cause metal backing plates to contact rotors, resulting in squeaking. Cold brakes squeak due to improper seal between pads and rotors. Warped rotors also cause brakes to squeak and pulsate when stopping slowly.

Before proceeding further, I would highly recommend you to have a brief overview of each component of a disc brake. It will help in troubleshooting brake-related issues easily. I have explained the working of disc brakes with a proper diagram. So, please visit the link and check that out.

Causes Of Brakes Squeak When Stopping Slow

Here are the causes of brakes squeak when stopping slow:

1. Buildup Of Brake Dust On Brake Disc

brake dust buildup

Brake dust is a mixture of metal shavings and adhesive materials that accumulate on the surface of brake pads and rotors as they wear down due to friction.

When you press on your brakes, the brake pads clamp down on the rotors, generating heat and friction that slows down your vehicle.

Over time, this constant wear and tear can cause the surface of the brake pads and rotors to break down and shed small particles of metal and other materials, which then stick to the surrounding surfaces and form a layer of brake dust.

In the case of brake dust, the particles can accumulate on the surface of the brake pads and rotors, creating an uneven layer that can interfere with the smooth operation of the brakes. This can cause the brake pads to vibrate in a way that creates a high-pitched squeaking sound as you come to a stop.

Also Read: Brake pads not touching the whole disc

How to fix?

To effectively eliminate the squeaky brake noise and clean the accumulated brake dust, a combination of a garden hose and a brake dust cleaner is recommended.

It is important to opt for a non-toxic brake dust cleaner, especially if the rims or finish are delicate and require special care.

For an affordable and effective solution, P&S Brake Dust Cleaner, which is a foam-based cleaner to float the brake dust on top of the foam, can be preferred.

To get started, ensure that the brakes have cooled down before proceeding. Next, spray the brake dust cleaner onto the wheels and brake caliper, ensuring that the foam reaches the brake pads.

After a few minutes of spraying, the brake cleaner will effectively remove and drip out the brake dust. Finally, rinse the wheels and brake caliper thoroughly with a garden hose.

2. Accumulation Of Moisture Due to Condensation

rust layer on brake disc due to moisture accumulation

When your car is exposed to rain or other sources of moisture, such as humid air, the water can easily accumulate on the surface of your brake rotors.

While this may not seem like a big deal at first, the problem arises when the moisture begins to interact with the metal surface of the rotors. 

Over time, the accumulation of moisture on your brake rotors can cause a rust layer to form.

When this rust layer forms, it can cause your brakes to make a squeaking noise when you come to a stop. This happens because the rust creates a rough surface on the brake rotors, which causes the brake pads to vibrate and make noise. 

If brake pads are metallic, they will also develop the rust, and cause squealing noise from the brakes in the morning.

Apart from the rust resulting due to moisture, brake pads also tend to stick to the moistened surface of the brake disc, causing a high-frequency vibration. This vibration further generates noise, which can be quite annoying for the driver and passengers.

How to fix?

This is not a serious issue. One way to prevent brake squeaking is to drive your car around for a few minutes in the morning before applying the brakes. This will allow the brake discs to heat up and evaporate any moisture that may have accumulated.

Another process requires removing the wheel, brake calipers, and brake pads. After that, spraying CRC brake cleaner onto the brake disc and utilizing a steel brush to scrub and wipe it with a shop towel.

Make sure to thoroughly clean the brake disc. If particles of brake cleaner are left on the disc, they will damage the surface of the brake pad that is in contact with the brake disc.

Lastly, if rust has also formed on the brake pads, take 180 to 200 grit sand paper and sand down the brake pad surface to remove contaminants.

3. Warped and Scored Brake Rotor

scored brake disc

The brake rotor is a disc-shaped component that is attached to the wheel hub of your car.

The brake rotors can become warped and scored due to various reasons. Continuous braking for a long period of time, such as driving downhill, can cause the brake pads to overheat and the pad material to transfer to the surface of the rotor. This can create a glaze on the rotor and cause it to become uneven.

Another reason for warped and scored rotors is rapid cooling of the hot rotors. If you drive through a puddle of water or spray water on the hot rotors, the sudden temperature change can cause the rotor to warp.

Another common cause of warped rotors is uneven wear. If the brake pads are not wearing down evenly, it can create high spots on the rotor that eventually lead to warping.

Moreover, if lug nuts are not torqued to the manufacturer’s specifications, it can cause uneven pressure on the rotor, leading to warping.

A scored brake rotor is one that has developed grooves or ridges on its surface. This can happen due to wear and tear, improper installation, or using the wrong type of brake pads.

How they cause squeaky noise from brakes?

Warped and scored brake rotors can greatly affect the efficiency of your vehicle’s braking system. Brakes rely on a smooth and even surface on the rotors to create consistent friction and slow down the vehicle.

However, a warped or scored rotor creates an uneven surface that causes inconsistent friction and can lead to noisy and inefficient braking.

When you apply the brakes slowly, the brake pads press against the brake rotor with less force than when you apply the brakes quickly. If the brake rotor is warped or scored, it can cause the brake pads to vibrate, resulting in a squeaking noise.

How to spot and fix?

To remove light scoring marks, you can try using 120-grit sandpaper. Don’t forget to clean the brake rotor with rubbing alcohol or CRC brake cleaner.

Furthermore, you can also use Scotchbrite pad and rubbing alchohol to clean the brake rotors.

To inspect for scoring grooves on the rotor, run your fingernail along both faces of the rotor. In case your nail moves freely without catching in any groove, the rotor is in good condition.

However, if you detect a groove that is deep enough to catch your fingernail, it indicates the brake rotor is damaged, and you should replace it with a new one.

Warped rotors refer to the uneven thickness of brake rotors which can cause vibration in the steering wheel or a wobbling brake pedal while braking.

When brakes are applied, the brake pads grip the rotors and slow or stop the vehicle. If the rotor is not completely even, the pads won’t have even contact with the rotor, and this could result in the pads wearing unevenly, causing a vibration or pulsation in the brake pedal or steering wheel.

How to fix?

The most effective way to fix warped rotors is to have them replaced. However, if the rotors are only slightly warped, they may be able to be resurfaced or machined.

Resurfacing refers to the process of removing a thin layer of the rotor’s surface using a lathe. By doing so, the rotor’s surface is evened out, allowing for smooth and consistent braking.

Resurfacing is only recommended if the rotor is still thick enough to be safely machined and not too damaged.

A thinner brake rotor cannot dissipate heat as effectively, can cause brake fade, and may compromise the structural integrity of the rotor, leading to potential brake failure, which can be extremely dangerous.

4. Brakes Are Not Bedded-in Properly

If you have installed new brake pads or brake rotors, it is necesssary to bed-in them. During the manufacturing process, brake pads and rotors are treated with a layer of protective coating to prevent rust and corrosion.

However, this coating can also affect the performance of the brakes. Bedding-in removes this protective layer through a controlled process of heating and cooling.

Bedding-in is the process of breaking in new brake pads and rotors by gradually heating them up and cooling them down. This helps to transfer a thin layer of material from the brake pad to the rotor, which creates a more even surface and improves the overall performance of the brakes.

Moreover, bedding-in heats the brake pad and rotor to the proper operating temperature, which is necessary to remove any glaze that may have formed on the surface.

If bedding of new brakes is not performed correctly, it can cause squeaking or squealing noise at low speeds.

This is because the surface of the brake pad is not optimally matched with the surface of the rotor, leading to vibrations that produce an audible noise, which is more noticeable at low speed.

How to fix?

To properly bed-in brakes, follow these steps:

  1. Find an empty road or parking lot to perform the procedure.
  2. Accelerate to around 40-50 mph and then firmly apply the brakes to slow down to 10-15 mph.
  3. Repeat this process 10 times, allowing the brakes to cool between each application.This brings the brake rotors up to temperature so they are not exposed to sudden thermal shock.
  4. Make sure that you do not press the brakes too hard as it will activate ABS.
  5. After completing the bedding-in process, avoid coming to a complete stop for at least 5 minutes to allow the brake pads and rotors to cool down.

5. Brake Pads Are Vibrating Due to Improper Lubrication or Lack of Anti-squeal Shim

brake pads structure

The back of the brake pad usually has a shim incorporated onto it. This shim is a thin layer of metal or rubber that sits between the brake pad and the braking system. The main purpose of the shim is to absorb some of the vibrations coming from the brake pads and reduce the noise.

The shim functions as a cushion between the pad and the caliper, reducing the potential for high-frequency vibrations that create brake noise. When the shim is installed properly, it can significantly reduce the amount of noise coming from the brakes.

Moreover, shims are individually tuned to match Original Equipment Manufacturer (OEM) pads, which are designed to specific tolerances to work optimally with a vehicle’s braking system. Therefore, it is essential to use the correct shim for the brake pad you are installing.

It is not recommended to use old shims for brake pads as they will be worn-out and ineffective in absorbing noise and vibrations. However, shims can be cleaned and reused. The important thing to remember is to clean the shim thoroughly using brake cleaner and paper towels before installation.

Mismatched shims can cause problems with the brakes. This occurs because different brake pads can require shims of different thicknesses, and using the wrong shim can cause the pad to rub against the rotor creating noise or vibration.

To prevent this issue, it is essential to match the correct shim with the brake pads used on a particular vehicle.

Furthermore, using two sets of shims can cause a spongy pedal. The caliper may not clamp down on the rotor evenly, creating a pedal that feels soft and not very responsive.

If your brake pad does not have a shim, you can apply high-temperature and rubber-safe grease on the backing plate of the brake pad.

To prevent damage to the frictional material of the brake pad and rubber seals of the brake piston, it is crucial to use a high temperature grease. Melting and flowing of grease between the brake pad and rotor can cause significant harm in such a scenario.

To address this issue, I recommend using ATE Plastilube grease for lubricating the brake pads. For optimal results, apply a thin layer of this grease on the backing plate of the brake pad and ears, which include leading and trailing edges of the brake pads.

Final Thoughts On Brakes Squeaking When Stopping Slow

In summary, squeaky brakes when braking lightly can indicate several issues that shouldn’t be ignored.

Worn brake pads, accumulation of brake dust and moisture, warped rotors, improper bedding of new brakes, and lack of anti-squeal shims can all cause annoying brake squeaks at low speeds.

Addressing the specific cause, whether through cleaning, sanding, lubrication, or replacement of components, is key to restoring silent and effective braking.

Regular inspection and maintenance is crucial, as squeaky brakes reduce braking power, and can potentially lead to complete brake failure if left unchecked.

FAQs (Frequently Asked Questions)

Is it safe to drive with squeaky brakes?

Drive with caution and avoid excessive use of brakes. Have brakes inspected and repaired soon, as ignored squeaky brakes can fail completely.

How do I know if my brake rotors are warped?

Warped rotors cause vibration in steering wheel and brake pedal pulsation when braking. Visually inspecting rotor surfaces or using fingernail to detect grooves also indicates scoring/warping.

Do I need new brake pads if my brakes are squeaking?

Squeaky brakes during light braking can mean worn brake pads need replacement. But other issues like moisture or uneven wear can also cause noise.

What’s the easiest way to stop brake squeaking?

Cleaning brake rotors and pads of dust buildup using brake cleaner can often eliminate squeaky brake noise during light braking.

Are squeaky brakes dangerous or can I just ignore the noise?

Don’t ignore squeaky brakes as they indicate issues reducing braking power. This could potentially lead to brake failure and should be addressed.

Why do my brakes squeak when I’m stopping slowly but not when I brake hard?

rakes tend to squeak at low speeds due to buildup of dust, moisture, and uneven brake pad wear. Hard braking generates more heat and friction to mask the noise.

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