Squeal or squeak
A high squeal when you brake is the most common brake noise. Most pads have a small metal tab called a wear indicator. When the pad gets thin, the tab touches the rotor and squeals. The rotor is the metal disc the pads squeeze.
A squeal can also come from glazed pads, cheap pads or a bit of rust. A short squeak on a damp morning is often nothing. A squeal that shows up every time you brake means it is time for a check.
Brake dust plays a part too. Some pads on BMW and Mercedes-Benz cars make a lot of dust. Dust and heat can leave a glaze on the pad. A glazed pad squeals and does not grip as well. New pads and a clean rotor surface fix it.
Grind
A grind is a deep, rough sound. It often means the pads are gone. Now the metal backing plate is rubbing on the rotor. That ruins the rotor fast and hurts your stopping power.
A grind can also be a small rock stuck between the rotor and the dust shield. Either way, do not wait. Grinding brakes are not safe. Call us and we will get you in.
Click, clunk or rattle
A click when you first press the pedal can mean the pads are loose in their bracket. Worn clips and hardware let them shift. A clunk can mean a loose caliper bolt. The caliper is the part that pushes the pads.
A rattle over bumps that stops when you brake is often a loose pad or a worn shim. None of these are urgent by themselves. But loose parts wear out fast, so have them looked at soon.
Thump or pulse when you brake
A thump or a pulse in the pedal usually means a warped rotor. Heat from hard stops can make the rotor uneven. You may also feel a shake in the steering wheel at highway speed on the Loop.
Sometimes the rotor is fine and the wheel bearing is the problem. We measure the rotor with a gauge. Then we know which one it is. Rotors on many German cars are made to be replaced with the pads, not turned. Turning means shaving the rotor flat on a lathe. We will tell you which your car needs.
Noises that are not the brakes
Not every noise when you slow down is the brakes.
We check all of these when you bring your car in for a noise. That way you fix the real cause.
- A hum or growl that changes with speed is often a wheel bearing.
- A click on turns is often a CV joint. That is the joint in the axle that lets the wheel turn and steer.
- A clunk over bumps can be a worn sway bar link or a ball joint.
- A whine when you brake hard can be the ABS pump doing its job.
Brake wear sensors on German cars
Many BMW, Mercedes-Benz, Audi and Volkswagen cars have a brake wear sensor. It is a small wire in the pad. When the pad gets thin, it sets off a light on the dash. You may see the light before you hear any noise.
The sensor is replaced with the pads. Hear a noise or see a light? Call Athens Import Auto Repair at 706-353-3880. We check brakes on imports every day at our shop on Winterville Road in Athens, GA.
Key takeaways
- A squeal usually means thin pads.
- A grind means metal on metal. Do not wait.
- A click or clunk points to loose brake hardware.
- A pulse in the pedal usually means a warped rotor.
- Some noises are bearings or joints, not brakes.
