Dietmar Rabich / Wikimedia Commons / “Dülmen, Wiesmann Sports Cars, Wiesmann GT MF5 — 2018 — 9603” / CC BY-SA 4.0

The braking system of a car is what enables the car to come to a stop.  Keeping the braking system in optimum condition is important for your safety, and also for the safety of others on the road.  Brakes that don’t work properly can prevent you from stopping when needed and can cause accidents.  The most common indicator of an issue with your braking system, aside from the feel of the brakes when you press the pedal while driving, is the noise they make.

There are two main types of noises that the brakes will make when there is an issue.  These noises are rattling and grinding.  Brake rattling sounds similar to the sound made when shaking a can of spray paint.  The sound is usually due to heat expansion causing the shims to rattle.  Anti-rattle shims solve this problem.  The second noise, and most worrying, is the sound of grinding coming from the brakes.  The most common noise to indicate that there is a problem with the braking system is grinding.  A grinding noise coming from the brakes of your car can happen for many reasons.  Not all of them will require a complete brake job.  The following list outlines the main reasons your brakes grind.

Reasons why your brakes are grinding

1.  Worn brake pads.  On average, the brake pads of a car last 40,000 miles.  Sometimes more, sometimes less.  How you drive and how you brake plays a large part in how long they will last.  The most common reason for the sound of grinding when the brakes are applied is that they require replacement.  You can continue to drive with worn brake pads but your braking time will be severely compromised.  Caution should be used as this can lead to more extensive, and expensive repairs.

2.  Metal spot on brakes.  Depending on the type of brake pads installed on your car, the sound may be the regular wear and tear of a larger spot of metal within the brake pad.  This is most often seen on inexpensive or low-quality brake pads but can also occur for a short period of time on a regular brake pad.  If the noise goes away after a short period of time it is probably nothing to worry about.

3. Brake wear indicator.  The brake wear indicator, also known as the wear bar, is a clip attached to the brake pad which makes a grinding metal noise to indicate to the driver that the brake pads will soon be in need of replacement.

4. Rusted brake pads. If the car is not driven very often the brake pads can accumulate rust which will cause a grinding noise.  If the brake pads are rusted it is very possible that rust could have also spread to other parts of the braking system.  This can affect the effectiveness of the braking system as a whole and be quite dangerous.  Caution should be used when driving a car that has not been driven for a while.  If the problem continues, the car should be taken into a licensed mechanic as quickly as possible.  It may not be safe to continue driving.

5.  Rotor wear.  Rotors, also called brake discs, are what the car’ brake pads clamp down on to stop the wheels from spinning.  They generally last 50,000-70,000 miles.  If you do a lot of highway driving, which often entails braking hard from fast speeds, the rotors may require more frequent replacement.  Rotors in need of replacement will often make a screeching noise as opposed to grinding.  Warped rotors can also cause brake pads to wear faster, which will lead to that dreaded grinding noise.  If you are having to replace the brake pads sooner than the average listed lifetime, have the rotors checked for warping and hot spots.

6. Cheap brake pads.  Cheap brake pads can seem like a good idea when you see the price.  The problem is that they tend to be poorly made and can have large chunks of metal in the pad which can scrape against the rotor making a grinding noise, and possibly causing severe damage.  Low-quality brake pads should be avoided in all but a financial emergency.  Low-quality brake pads can be better than badly worn brake pads but you will need to get them replaced sooner so the cost savings may not be worth it.

7. Wheel bearings issues.  A worn or damaged wheel bearing can cause uneven wear on the brake pads and/or rotors.  This can be caused due to a warped rotor.  If you have ruled out the other possibilities, have a licensed professional take a look at the wheel bearings for any wear and tear or other possible issues.

8. Something in the brake calipers or pads.  Debris may have made its way into the braking system.  This may cause a grinding noise and possibly produce a vibration.  This can cause a realignment of your brake pads causing uneven brake wear.

9. Brake caliper bolts need lubrication.  Like most other moving parts on your car, brake caliper bolts need lubrication.  If not properly lubricated you may hear a grinding noise coming from the braking system.

10. Damaged shims.  Shims replacement is often overlooked in fast or inexpensive brake replacements.  The shims will eventually wear down.  This can cause them to make contact with another part of the braking system such as the rotor.

The braking system is one of the greatest safety features of your car.  Ensuring that all components are in great shape and working well will not only save you money but prevent you from getting into accidents.  Remember when in doubt, have it checked out!