What is it?
Brake noise usually occurs when you apply the brakes but can also occur when driving normally, the noise comes from the brake components and is something such as a metal-to-metal grinding sound, squealing or even a repeating click sound.
What causes it?
There are a number of possible causes, common causes are but not limited to include:
- Worn out brake-pads – Lack of brake material on brake-pads
- Brake components rattle – Components of the braking system not fitted correctly/Lack of brake-pad shim
- Slotted/Drilled rotors – The grooves and holes on the rotor surface
- Shims, these are thin layers of either metal or rubber which correct alignment defects and act as an anti-rattling piece. Depending on the brake-pad, some come with a shim already attached. Otherwise they can sometimes be purchased separately and then later be applied to the brake-pads.
- Incorrect/Incompatible brake-pads is another possible cause, cross-reference the brake-pad part number to ensure you get the correct part. Brake-pads look similar in design and can be easily mistaken for each other, using a smaller brake-pad can be dangerous. Using the incorrect part can also lead to other hazards such as damage to other components and causing the calipers to jam.
- Brake-pads are made out of different materials and compounds, depending on which is used can lead to noise occurring.
- If you have Slotted/Drilled rotors fitted to your car, this may be the cause. The grooves and holes on the rotor surface make noise when moving which is normal, if the brake-pad has been bedded-in then the noise can be reduced.
- Manufacturers now sometimes offer a coating on their disc brake rotors such as colored finishes or protective finishes. If the coating was not applied evenly it may cause noise to occur, if the rotor is new and coated the noise may reduce with more usage.
- Warped Rotors have uneven braking surfaces, this can result in noise when braking. If you have warped rotors it is best to get them machined or replaced completely.
- Loose wheels can also be another cause of noise, check the wheel/lug nuts are screwed in and the rotor is sitting securely without any wobble.
- Check your brake components, in particular the brake calipers for any dirt, grime or rust. These can prevent the brake-pad from sitting correctly and lead to noise. If necessary some grease can be lightly applied on the backing plates – Never apply grease/lubricants to the surfaces of the rotor & brake-pads where they come into contact
- Completely new disc rotors/brake-pads may have noise at first, after the bedding-in process and more usage the noise may disappear or dramatically be reduced.
How is it fixed?
For worn out brake-pads the solution is simple, replace the brake-pads with new ones. Driving with brake-pads that have low or no braking material left can lead to longer braking distances and time.
For rattling components, it is important to inspect your braking system.