Vehicles are designed to be driven regularly, and having your vehicle in storage can be extremely hard on a variety of vehicle systems, including the brakes. Because the brake system is exposed to the elements while driving, it is common for rust to develop on brake parts, especially the brake rotors. Rust buildup on the rotors can cause both grinding and scraping noises during braking. In some cases, rust may prevent the calipers from applying even pressure or the brake pads from making complete contact with the rotors, and you may not be able to stop your vehicle. In many cases, rusted rotors will be “cleaned” by the brake pads the first few times you brake, but this may not always be the case. If your vehicle has been sitting for more than a month, it is recommended that you inspect your brakes for any rust that may not allow your brakes to operate properly. If your brake rotors have too much rust to operate properly, many local O’Reilly Auto Parts locations offer brake rotor resurfacing near you to return your brakes to operational condition.
Getting looks from other drivers when your brakes grind or make noise can be more than just embarrassing, it can be an indication of a safety issue that needs to be addressed. Brake systems are designed to operate quietly and efficiently, but there are times when a problem with one or more parts of the system can make them noisy. Because brakes are vital to driving safety, diagnosing any brake grinding or noticeable noise should be a priority.
Brake systems slow your vehicle by using hydraulic pressure to compress the brake pads against a brake rotor. Modern brake pads are made of friction-reducing materials like graphite, steel, or brass to reduce heat and extend the life of the friction material on the pad. These materials also help brakes stay quiet, but because brakes generate friction to stop the vehicle, there may be more than one reason the brakes on your vehicle may begin to make noise or grind.
Worn Brake Pads or Brake Hardware
The most common source of brake grinding or brake noise is worn-out brake pads. Many brake pads are equipped with a metal tab, called a wear indicator, that rubs against the rotor to make noise when the friction wears to a specific point and it is time to replace the brake pads. If the brake pads are not equipped with a wear tab, you may not hear any noise until the brake friction material is completely worn off and the metal backing plate of the brake pad makes direct contact with the rotor. When this occurs, you will hear a metal-on-metal grinding noise, and may even feel vibrations in the brake pedal. Adding a brake inspection to your normal maintenance or tire inspection routine can help you determine when it is time to replace the brake pads and prevent any damage caused by worn or damaged brake pads.
Over the life of the brake pads, the brake hardware will also wear out or become corroded. Most brake pads are held in place with thin metal hardware clips which can rust or corrode depending on local weather conditions, or they can wear due to brake pad vibrations. When the hardware begins to wear out, the brake pads and hardware will loosen slightly and may cause squeaky brakes. Most new brake pad sets come with new brake hardware, and it is recommended to replace the old hardware with new hardware every time you change your brake pads. Replacing the brake hardware with every brake pad change will help hold the brake pads securely in place and reduce the vibrations that cause brake noise.
Low-Quality Brake Pads
When purchasing brake pads for your vehicle, it is easy to pick the most budget-friendly pad without a second thought. However, trying to save a few dollars can lead to more frequent replacements or more expensive repairs. Lower-quality brake pads normally contain more metal content than brake pads that contain more costly friction-reducing materials such as ceramic or graphite. Higher metal content in brake pads can create more vibrations or noise and can lead to excess or premature brake rotor wear. Lower-quality brake pads may also generate more heat and brake dust, which causes them to wear out more quickly and can result in wear to other brake and wheel-end parts. Replacing worn brake pads with higher-quality brake pads can prevent excess wear to all the parts of the brake system and save repair costs in the long term.
The Brake Rotors Need to be Replaced
Brake rotors are the discs that the brake pads contact when braking, and like brake pads, they wear out over time. Most brake rotors are made of cast iron or an iron or steel alloy, and they are designed to last between 30,000 to 70,000 miles. However, there are conditions that can cause the brake rotor to wear prematurely or unevenly, which can lead to noise, grinding, or vibrations. Any issues with worn or uneven brake rotors may be repaired by replacing or resurfacing the rotors.
“Warped rotors” is a common expression that may be used to explain brake noise or vibrations. However, this term can be misleading as modern cast iron brake rotors do not warp. The noise or vibrations from brake rotors may be from a variation in the thickness of the rotor caused by runout. Runout is the amount of wobble that occurs as the wheel rotates, and can be caused by rust, debris, a bent hub, a bad wheel bearing, or any wheel-end part that is out of tolerance. All of the parts that are out of tolerance combine for the total stacked runout. Runout should be evaluated each time a rotor is removed or installed, and it can be measured with a dial indicator on the rotor as it is rotated. Runout is repaired by cleaning the hub and rotor, using shims on the inside of the rotor against the hub, or by resurfacing the rotor with an on-car brake lathe. In many cases if the runout has been caused by a buildup of friction material on the face of the rotor, simply resurfacing the rotor may allow it to be returned to service successfully.
In order to restore a flat surface for new brake pads to contact, brake rotor resurfacing, also known as turning rotors, or replacing the brake rotors is usually recommended. If the rotors are not turned during a brake job, the surface could be uneven or a lip may be present on the edge of the rotor. Uneven or worn rotor surfaces could cause grinding, vibrations, or noise while braking. If the brake rotors are under the recommended thickness, they should be replaced and not resurfaced. Most O’Reilly Auto Parts locations offer brake drum & rotor resurfacing and can assist you with parts or repair recommendations if you are repairing your own brakes.
Rusted Brake Rotors
Seized or Sticking Brake Calipers
Corrosion is one of the main reasons the brake calipers on your vehicle may stick or seize. When a brake caliper sticks, you may notice that your vehicle pulls to one side when you apply the brakes. This may be due to the caliper piston locking up and no longer moving in or out as it should. This can cause the brake pads to fail to make complete contact with the rotor, or it may keep the brake pads pressed against the rotor and cause accelerated pad wear, pulling, and wheel drag. A seized brake caliper can cause brake noise or grinding and should be addressed as soon as possible. Keep your brake calipers operating smoothly by lubricating them during regular brake maintenance and inspecting the condition of the piston and piston seal. If any part of the caliper is damaged or if the seal is torn or leaking, your brake calipers will need to be replaced.
Brake Grease & Lubrication
Since there are so many moving parts in a brake system, lubrication is necessary in key areas to keep everything moving smoothly. Brake caliper bolts or guide pins are one of the most common areas that require lubrication to operate as they should. The brake caliper bolts or guide pins hold the brake caliper firmly in place and allow it to slide freely to compress the brake pads against the brake rotors. If the lubricant on the brake caliper bolts dries out, it can cause excess vibrations and noise as the brake caliper actuates and can cause binding. It is recommended to lubricate the caliper bolts with brake caliper grease at least every time the brake pads are changed. If there is any pitting on the smooth surface of the caliper bolts or pins, they should be replaced and not reused. Reusing pitted caliper guide pins or failing to lubricate them as needed could cause uneven brake pad and rotor wear, premature failure, or could result in a stuck caliper.
Something is Lodged Between the Brake Pad and Rotor
Whether driving your vehicle on pavement or a dirt road, there may be debris on the road that could become stuck between the brake pad and rotor. The debris could include a rock, a piece of wood, a nail or screw, or a variety of other items. Depending on how the debris is lodged in the brakes, it could cause symptoms such as noise, grinding, and vibrations. In some cases the debris may free itself when the vehicle slows, stops, or is reversed, but in other cases, the brakes on the affected wheel may need to be disassembled to manually remove the debris. If the debris is not removed quickly, it could damage the brake pads, the brake rotor, or both, and could prevent the brakes from grabbing or properly engaging the rotor. This could also cause your vehicle to pull to one side while braking, and any effects caused by debris in the braking system should be addressed quickly.
Bad Wheel Bearing
Wheel bearings are not normally considered part of the braking system, but they are responsible for the rotation of not only the wheel, but also the brake rotor. A wheel bearing may begin to vibrate or make grinding noise as it wears out, if the bearing is low on grease or the grease has been contaminated, or if debris accumulates inside the bearing. Vibration or noise from wheel bearings may occur while braking similarly to the effects of warped rotors or damaged brake pads, but wheel bearing issues may only occur during acceleration or at a certain speed. If the vibrations or noises are coming from the wheel bearings, they may need to be greased or replaced. Inspection of the bearings and the braking system can help determine whether they are the source of the noise, and checking the wheel bearings for play is a good way to see if they have begun to fail.
Driving with The Parking Brake Engaged
It may seem like common sense, but driving with the parking brake engaged may create brake grinding and noise. Other than noise, driving with the parking brake engaged will make your vehicle’s acceleration feel sluggish, and it may rapidly decelerate when you let off the gas pedal. The brakes and wheel-end may also overheat if driven a long distance with the parking brake engaged, and this can result in excess wear or damage to the brakes, wheel bearings, and other wheel-end parts. Simply checking and disengaging the parking brake before driving can help prevent wear that may be caused while driving with the parking brake engaged.
Can I Drive My Vehicle if the Brakes are Making Noise?
Brake noise or grinding sounds coming from your brakes may be annoying, but also point to a potential safety issue. It is recommended that you drive your car as little as possible when your brakes are grinding until you have an opportunity to have the brakes inspected or repaired. If you are unable or unsure of how to properly inspect or repair your brakes, we would be happy to recommend a trusted local repair shop for you. You can also check out our brake repair videos for an in-depth look at how to perform a brake pad and rotor replacement yourself.
We hope this has helped you understand what may cause brake noise and brake grinding. You can visit your local O’Reilly Auto Parts if you have questions about brake parts or brake issues, or you can shop our brake parts selection to find the parts you need to complete the repair on your vehicle.