7 Causes of Grinding Noise When Braking

Hydraulics are used to provide functionality to the brakes of vehicles. Each wheel of a vehicle is going to have an individual brake built into it.

These brakes typically consist of a brake pad which creates friction against a brake rotor in order to slow down the vehicle. All these braking functions are controlled through a hydraulic system. This is how stepping on the brake pedal will cause the wheels to slow down or stop spinning.

Since most of the vehicle’s weight is pushed toward the front of the vehicle, it is the front wheel brakes that will endure the most wear and tear. They are under more pressure to slow down the vehicle after you step on the brake pedal.

For this reason, disc brakes are used for the front wheels of every vehicle even when drum brakes are used in the rear. Most vehicles have disc brakes on all four corners.

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Reasons for Grinding Sound When Braking

When you normally step on the brake pedal, it should feel nice and smooth as the vehicle slows down. But if you experience vibrations or hear strange grinding noises as you are stepping on the pedal, then something must be wrong in your braking system.

Below are seven of the most common causes of grinding noises and vibrations as you step on the brake pedal.

1) Dry Caliper Bolts

brake caliper bolt

The caliper bolts have slides which need to be lubricated at all times. Otherwise, if they are dry, there will be grinding sounds coming from them. While it’s not a common occurrence, it can happen on occasion.

People who are driving older cars might have a bigger chance of having dry caliper bolts. If so, just get local auto repair shop to add grease to them or simply have a brake job done if you need new pads or rotors. Lubricating the brake caliper bolts is also an easy DIY job.

2) Worn Brake Rotors

rusty brake rotor

Healthy brake discs will be flat and won’t cause any noise during the braking process. However, brake rotors tend to become worn out as you continue to use them over the years and corrosion or rust can cover areas on them.

They will eventually become uneven instead of flat, resulting in loud squeaking sounds to be heard each time you step on the brake pedal. If they become warped because too much cold water made contact with hot rotors, you will notice a slight grinding noise with every revolution of the wheel.

3) Worn Brake Pads

minimum brake pad thickness

The most common cause of noises from the braking system is worn brake pads. As you continue to use your brake pads, the material on the front each pad will get used up and you’ll eventually surpass their minimum thickness.

Once enough of the friction material is gone, the metal from the backing plate will show through. Once this metal makes contact with the surface of the brake rotor, it will create a lot of grinding noise and other sounds as it gouges into the rotor.

Not only will the noise be loud and annoying, your brake rotor will need to be replaced from the damage.

4) Bad Shims

brake pad shims

Brake shims are designed specifically for preventing noises to occur between the brake discs and brake pads. These shims are merely rubber layers which go between the two components.

The material can easily diminish as time goes on. As a result, they won’t be able to prevent brake noises as much anymore.

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5) Rust or Corrosion


disc brake rotor

With all these metal pieces in your braking system, you need to keep them moving on a regular basis. If you just let your car sit in a garage for weeks or months at a time, you can expect these metal components to form rust and/or corrosion from normal air moisture.

Once that happens, you will experience all sorts of strange noises coming from your brakes until you either clean these components or replace them, depending on the severity of the rust or corrosion.

6) Brake Debris

brake caliper slides

There could be foreign debris stuck inside your braking system that is causing those noises. Perhaps a small rock or pebble flew into the caliper area and got stuck there.

If you have any hard debris like this in between the caliper and the disc brake, then you will certainly have here some noises. In addition, the debris will likely damage your brake rotor if not removed soon.

7) Bad Wheel Bearing

bad wheel bearing symptoms

A bad wheel bearing could create inconsistent noises from your braking system. Sometimes they will be loud while other times they will be soft and quiet.

Don’t leave this to chance. Replace a bad wheel bearing right away.


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