Why Do My Brakes Squeak In The Morning?
Do you ever find yourself waking up in the morning, starting your car and hearing an unpleasant screeching sound coming from your brakes? That high-pitched squeak or squeal can be a jarring way to start your day, and it can leave you wondering if something is wrong with your vehicle. The truth is, a squeaky brake isn’t always a sign of something major, and it can be a common occurrence.
However, it’s still important to understand why your brakes are squeaking in the morning, so you can take action to prevent more significant issues down the road. In this article, we will explore the various reasons why your brakes might be squeaking in the morning and offer some solutions to help fix the issue.
So, why do brakes squeak in the morning? When your car sits idle overnight, moisture can accumulate on the brake rotors. When your car is parked outside, it’s exposed to the elements, including dew and humidity. When you hit the brakes in the morning, the moisture gets wiped away, causing a momentary layer of rust to form on the rotors. This rust can cause a slight grinding sound, which is often mistaken for a squeak. Additionally, your brake system may need some lubrication. Your brake calipers and pads need to move freely in order to function properly. If they become stuck, this can cause a squeaking noise.
Also Read: Groaning noise when braking at low speed
Table of Contents
Overview of Disc Brakes: Key Components and Mechanics
Before proceeding towards discusssing the causes of brakes squeaking in the morning, I will first walk you through the components of disc brakes, and their mechanics. It is important to first understand their working as it will help in troubleshooting all brakes related issues.
Disc brakes consist of the following components:
- Caliper guide pins
- Caliper bracket
- Brake pads
- Brake disc
The caliper is the part that actually applies force to the brake pads. It is a clamp-like mechanism that moves with the help of brake fluid from the brake pedal. When this happens, the caliper applies pressure to the brake pads, forcing them to move towards the rotor.
Caliper Guide Pins and Bracket
Caliper guide pins ensure that the brake pads remain in contact with the rotor equally. These small metal pins allow the caliper assembly to move freely in the correct direction, promoting even wear on the brake pads. The caliper bracket connects the caliper to the steering knuckle and suspension system, and it is essential for this connection to be strong and stable.
In the below video, you can see how caliper moves along the guide pins:
Brake pads are seated in the caliper bracket. While each wheel has two brake pads, the inboard pad is located on the inside of the rotor (closest to the vehicle’s center), and the outboard brake pad is located on the outside of the rotor (farthest from the center). When pressure is applied to the brake pedal, the pads grip both sides of the rotor, generating friction to slow down or stop the vehicle.
The brake disc or rotor is attached to each wheel and spins along with it. When the brake pedal is pressed, the caliper squeezes the brake pads against the rotor surface, creating friction that ultimately slows down the rotation of the wheel and the vehicle itself.
Hydraulic Action of Brake Caliper
When the driver presses the brake pedal, hydraulic fluid is pushed through the brake lines and into the caliper. The piston, in turn, presses the inboard brake pad against the rotor.
Meanwhile, the brake fluid exerts force in the opposite direction, moving the brake caliper along the caliper pin. Due to this action, the outboard brake pad is also pressed, causing the brake disc to be squeezed between both brake pads and apply stopping power.
Recoiling of Brake Pads After Brake Pedal Is Released
The brake caliper piston has a square edge seal, which helps the piston move and apply the pressing force. When the driver releases the brake pedal, the pressurized brake fluid is no longer present, causing the seal on the piston to snap back into its original shape. This action pulls the piston back slightly, creating a small gap between the brake pad and the rotor.
The square edge seal on the caliper piston creates a kind of resistance to rolling over, which helps create the necessary margin clearance needed to separate the brake pad from the rotor surface.
Once the rotor starts turning again, centrifugal force is used to produce a pocket of air around the rotor, which assists in pushing the brake pads back from the rotor surface. The presence of dirt and air gaps in the pads can impact this process, which is why keeping lubricated pads and slide pins and removing air gaps is essential for maintaining proper brake pads pressing and retraction.
Bonus Read: Why do my brakes squeak when I first start driving
Causes Of Brakes Squeaking In The Morning
Brake squeaking occurs when the brake pads vibrate against the brake disc, causing a high-pitched noise. When moisture is present on the brake disc, it can cause the brake pads to stick and vibrate more than usual, resulting in a louder noise.
So, keeping in view this, here are the causes of brakes squeaking in the morning:
1. Moisture Developed On The Brake Disc
When a vehicle is parked overnight, the brake discs become exposed to the elements. The moisture in the air can condense on the surface of the brake discs.
Since brake discs are made of metal, this moisture can cause a thin layer of rust to form on the surface of the disc, which can make the brakes squeak when they are applied in the morning as the brake pads tend to scrape off the rust layer of brake disc. The rust on the brake disc can also cause the brakes to feel less responsive or even stick.
Also, if you let your car sitting for a long time with the above condition, the rust could be bad enough and could spread all over the rotor. 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?
One way 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 developed overnight.
Fixing brakes that squeak due to moisture and rust buildup involves a relatively complex procedure. The 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.
2. Stuck Brake Pads Due to Seized Brake Caliper
If you are experiencing a squeaking sound when you apply the brakes, there are several potential causes. One common issue is stuck brake pads due to a seized brake caliper, specifically the pin that holds the caliper in place.
The caliper is responsible for moving the brake pads in and out as the brakes are applied and released. The caliper moves on a set of pins when you press the brake pedal.
When the caliper pin becomes seized, the caliper cannot move freely to allow the brake pads to properly release from the rotor. This can cause the brake pads to remain in contact with the rotor, even when the brake pedal is released. As a result, the pads can wear down more quickly, and you may notice a squeaking sound when you apply the brakes.
How to fix?
To maintain your brake system, you will need a brake cleaner and wire brush to eliminate any debris or rust present on the brake caliper pin. Additionally, ensure that the debris and dirt inside the caliper pin hole must also be removed.
To clean the caliper bore where the pin moves, use a brush that fits. Dip a bore brush or cotton swab into the cleaning solution and carefully wipe the hole’s interior.
After cleaning, apply a high-temperature brake lubricant to help prevent friction and ensure smooth movement. I recommend this particular lubricant for optimal results.
3. Brake Pads Vibrating and Need To Be Lubricated
Brake pads seat into the retaining clips of the caliper mounting bracket as shown in the figure below:
Brake pads glide smoothly along those retaining clips when brake caliper pushes the brake pads. When there is unsufficient lubrication, and brake pads are not able to smoothly glidely, they will not be able to recoil back smoothly after brake pedal is released.
As a result, brake pads will remain in contact with the brake disc, and vibrate, which will cause squeaking or squealing noise from the brakes. This is particularly noticeable in the morning, when there’s dew on the rotor. The moisture can make the brake pads stick to the rotor, making the vibration and noise even worse.
How to fix?
Due to trapping of moistures, brake pads do not glide smoothly. So, you need to remove them and apply high-temperature lubricant on the ends of the brake pad that are in contact with retaining clips. I would recommend ATE Plastilube Grease. Make sure that you clean any dirt and rust before applying the grease.
4. Cold Weather Causing Brake Components to Contract
If you’ve ever heard a high-pitched squeal or screech when you first hit the brakes in the morning during the colder months of the year, you may have wondered what’s causing that annoying sound. The good news is that this is a common issue that many drivers experience, and it’s usually not a serious problem.
One of the main reasons that cold weather can cause brakes to squeak in the morning is related to moisture. When the temperature drops overnight, the metal parts of your car, including the brake rotors and pads, can become covered in a thin layer of condensation or frost. This moisture can cause the brakes to feel a bit more slippery or sensitive than usual, and it can also contribute to the squeaking noise when you first apply pressure to the brake pedal.
Moreover, When the temperature drops, the metal used in brake rotors and pads contracts, causing them to become harder and less pliable.
As a result, when the brakes are applied, the pads create more friction than usual, which can result in a squeaking sound. This is particularly true when the brakes are first applied in the morning, as the rotors and pads have been sitting in a cold environment for an extended period of time.
How to fix?
One simple way to reduce the amount of moisture on your brake system is to give your car a few extra minutes to warm up before you hit the road. This can help evaporate any moisture that may have accumulated overnight and also give your engine and other systems a chance to warm up to operating temperature.
After you lightly apply the brakes a few times, they will heat up, and the moisture layer will be gone along with your squealing noises.
Lastly, try to avoid slamming on your brakes in cold weather, as this can increase the friction between your brake pads and rotors.