If you’re driving down the streets of Austin and you suddenly start hearing a metallic sound when you press down on the brake pedal, it means there’s an issue with your braking system. If you hear your brakes making a grinding noise, whether you’re applying the brake pedal or not, you should bring your car to a service centre as soon as possible.
The National Highway Safety Administration estimates that up to 25% of road accidents are related to faulty braking systems, so it’s essential that you get any brake-related problems addressed right away. So if you find yourself asking, “Why are my brakes grinding?”, you’ve come to the right place!
Why Are My Brakes Grinding?
Hearing strange noises coming from your car can be pretty unnerving, and a grinding sound can be downright scary! Grinding brakes usually sound like a gritty, metal-on-metal sound. It’s a pretty distinct noise that’s certainly not pleasant on the ears.
If you hear this sound, it likely means you’ve worn out your brake pads to the point of exposing their metal backing plates, which are now rubbing against the metal of your brake rotors.
Not only does this put you in danger of brake failure on the road, but it may also damage the rest of your braking system, including the rotors and calipers. While replacing brake pads is simple, neglecting to do so can lead to more complicated problems!
How Grinding Brakes Affect Stopping Power
Not sure how a worn-down brake pad can make it harder to stop your car? Here’s how it works.
When you press down on the brake pedal, brake fluid is sent to the calipers — a metal device on your wheels. The brake fluid causes the calipers to squeeze the brake pads, which press against the brake rotors. The friction from the brake pads against the rotors slows and eventually stops the wheels from spinning.
If your brake pads are excessively worn, the metal backing on them can become exposed, allowing the rotors and metal to grind against each other when you brake. Not only does this cause an unpleasant sound, but it can also damage your rotor, reduce your brakes’ responsiveness, and lead to brake failure.
Grinding from worn-out brake pads and rotors is just one of many brake problems that may reduce your stopping power. Your brakes can make all kinds of noises throughout the life of your car, whether or not there’s an issue with their parts.
That’s why it’s important to get a free brake check when your brakes start “acting” funny, so you can find out if you have brake problems, what they are, and how much attention or which services they require.
Common Causes of Noise and Vibration when Braking
When you hear an annoying sound such as grinding, rubbing, squealing, or metal scraping sound while driving and applying the brakes, then you may have a problem. Sometimes it might be nothing and the sound will go away on its own.
But if the sound is consistent and does not go away or even gets worse, you likely have some type of brake issue. Here are 9 reasons for why this brake noise occurs.
#1. Worn Brake Pads.
If you hear grinding or whooshing when you step on the brake pedal, then it could mean that your brake pads are worn out. As the backing plate loses its material, this causes metal to come into contact with the metal on the rotor. Either that or the brake caliper itself may be making contact with the rotor.
Whichever one it is, your brakes could become severely damaged if the pads are not replaced. Your rotor could be destroyed by the backing plate, resulting in damage and grooves. The rotor will then do the same thing to the caliper. When your brake pads go bad, you need to get them replaced ASAP.
If you’re hearing a grinding noise when braking but the pads are fine, keep reading.
#2. Bad Quality Brake Pads.
Don’t try to save money by purchasing the cheapest brake pads you find. Skimping on poor-quality brake pads can literally mean the difference between a near collision vs a totaled car with serious injuries.
In addition to performance, cheap brake pads are poorly manufactured and can have defects such as metal chunks in the pad material which can scrape against the rotor and cause severe damage.
You will save money in the long run by choosing a reputable brand for your brake pads. Some of the best brake pad brands include Akebono, Stoptech, Wagner, EBC, Powerstop, and AC Delco.
#3. Worn Shims.
Any time you get a brake job done or replace brake pads yourself, you must replace the shims. Bad mechanics may avoid this if they want to do their job fast, so make sure they do replace them.
Brake shims that are not replaced will eventually get worn down. This can often result in a piece of the brake shim making contact with the rotor or other metal part of the brake system.
With metal touching other metal like this, you will hear sounds from your braking system as you drive the vehicle. So, make sure you replace the shims.
#4. Debris Stuck in Brakes.
Your brake system could have debris from the outside get lodged in it. This debris could be a piece of rock or gravel that gets stuck in the caliper.
Then, the debris will rest between the rotor and caliper, and cause scraping or grinding noises to occur and possibly vibration.
You’ll continue to hear these noises, even if you’re not applying pressure to the brake pedal. If the piece that’s lodged in there is not removed, your rotor may eventually get damaged and will at the least need to be resurfaced and possibly replaced.
Something stuck in your brakes can even cause your brake pads to get out of alignment and cause uneven pad wear. In this case, performance is reduced and you’ll need to replace your pads sooner than normal.
#5. Infrequent Driving.
A set of brake pads will usually last anywhere from 30,000 to 70,000 miles of normal driving depending on the type of vehicle and driving style. But if you start having braking problems sooner, then it could be from simply not driving your vehicle enough.
If the rotors don’t get used for a while, such as if a car is stored for the winter, then rust will eventually form on them or they may even get slightly corroded.
Other parts of the brake system may also develop rust so then you may have other issues such as your calipers sticking.
Because of the surface rust, the rotor is no longer smooth and can even has slightly raised areas where the rust forms, you may hear strange noises from your brakes while driving or braking.
Avoid this problem by not letting your vehicle sit too long without driving it. If a little bit of rust does form, it can often be cleared off by itself over time from the heat and friction of braking during normal driving. Too much rust will require resurfacing the rotors.
#6. Worn Brake Rotors.
If you have brake rotors that are worn or bad (warped, gouged, or cracked), they will make various sounds. Rotors that are warped and not flat will create squealing or squeaking noises. If the rotors are too worn, there may be scraping noises instead.
On top of that, worn rotors will create a lot of vibration from the braking system. The vibrations may come at irregular patterns and your foot will be able to feel them through the brake pedal in the form of brake shudder or your steering wheel will shake.
Sometimes rotors can be resurfaced (or turned) if they are slightly warped but if they are simply past their lifespan, rotor replacement will be necessary.
#7. No Lubrication on Brake Parts.
When installing brake pads, the brake pads’ backside need to be lubricated lightly using a brake caliper lube. If this simple step is ignored, then the metal of the pads and metal of the caliper piston will come together when you apply the brakes and make squealing or rubbing sound.
In addition, the caliper slider pins (which connect the two sides of the brake caliper together) should be generously lubricated before reinstalling.
#8. Caliper Bolts.
Brake caliper bolts should also be lubricated or else their slides will create sounds if they’re dry. This scenario is less likely to occur, but it could especially if it’s a DIY job. A reputable auto repair shop will at the least lubricate the bolts and often provide brand new bolts.
#9. Faulty Wheel Bearings.
This is probably the least likely reason for having brake noises. If grinding sounds can be heard from your wheels or if you experience vibrations that alternate from loud to quiet, then you could simply have a bad wheel bearing.
In addition to the noise, you’ll likely feel vibrations in your steering wheel while driving.
Brakes Grinding Situations
There are 3 main situations that could cause brake grinding:
Brake Grinding When You Press On Your Brakes
If you notice your brakes are grinding while slowing down, it’s probably due to a lack of thickness in your brake pads.
Your brake pads must be thick enough to provide adequate performance and halting power. Over time as you use your brake pads, they will eventually wear out.
When your brake pads are thinner than the suggested thickness, they will begin to screech every time you press the brake pedal. This uncomfortable sound is known as brake scrubbing, indicating that it is time to upgrade the brake pads.
If you ignore this noise, the brake pads will continue to wear out, and the squealing sound will become a grinding noise.
If your brakes make a sharp grinding noise while decelerating, the brake disc and caliper are likely scratching together. The sound often appears when your vehicle comes to a complete stop, but you may also hear it as you step on the brake pedal.
The best way to resolve this problem is to have your brake pads replaced as soon as possible, but you may also need to replace both your discs or rotors at this point.
Brake Grinding While Driving
If you hear your brakes grinding when traveling at a steady speed, that may be due to rocks or pebbles lodged between the caliper and the rotor. In this case, you’ll want the debris removed from the system as soon as possible. Lack of immediate action can severely damage the brake pedal and other performance components.
While you can remove rocks and debris from your brakes, hiring a professional is always best, especially if you’re new to working on cars. If you hear any brake grinding noises, you should schedule a service appointment with a car mechanic and have them inspect your vehicle.
Brake Grinding When Your Vehicle Comes To a Sudden Stop
Another common reason for a grinding noise from your brakes is when you suddenly slam the brakes. When you hit the brakes suddenly, you might hear a grinding noise and feel the brake pedal rattle. However, if your brake pads are sufficiently thick, you should not need to replace your brake pads.
If you hear grinding when you suddenly stop, it’s most likely caused by your Anti-Lock Braking System (ABS). In a panic stop, the ABS will start automatically to stop wheel lockups and vehicle skidding. The system operates by pumping the brakes to maintain stability and control, resulting in the grinding noise and rumbling brake pedal.
When to Replace Brake Pads?
Knowing when to replace brake pads is essential for your safety. Here are key signs it’s time for brake pad replacement:
- Squeaking or Squealing: High-pitched noises often indicate worn pads.
- Grinding Sounds: A grinding noise means the pads are worn down to the metal, requiring an immediate brake pad replacement.
- Reduced Brake Performance: If your car takes longer to stop or pulls to one side, it’s time to replace your pads.
- Visual Inspection: Pads thinner than 1/4 inch should be replaced.
- Warning Lights: Some cars alert you when it’s time for brake pad replacement.
Wondering how often to replace brake pads? This varies depending on your driving habits and the brake pad material, but it typically ranges from 25,000 to 70,000 miles. Regular inspections ensure your brakes perform at their best.