If you’ve ever experienced a bad brake squeal on your car, you know it’s one of the most awful sounds known to mankind. But what causes brakes to squeal and is there any way to stop it before it drives you over the edge of insanity?
Brakes can actually squeal in a few very different and annoying ways. Just like a child’s recorder, there’s a few different tones that come from each kind of squeal. No matter what the cause though, it comes all stems from vibrations.
When brakes squeal, they actually vibrate at a very high speed (the same way a speaker or a musical instrument causes vibrations). When they vibrate at just the right speed and power (or frequency), the brakes actually become sort of a musical instrument of their own and play you the song of their people.
With that said, what are the common causes for the brakes on your car to attempt to serenade you? While it might not cover everything, here’s a list of some of the things we’ve seen over the years that can cause problems.
1. Worn out brake pads – Brake pads usually have a small tab on the inside of each set which is called a squealer. While that might seem a little weird, it’s actually a really nice feature provided by the manufacturers of the brake pads to help inform the owner (you) that the pads are approaching the end of their life.
While this is the most common diagnosis from Dr Google for any brake squeal, in our experience it’s not usually the cause of the squeal. If you want to try to check your own brake pads, check out this blog on how to check your brake pads.
2. Poor pad material or rotor condition – Though it seems a little silly, most of the brake noises we’ve seen have actually come about after the brakes have been replaced already. It’s not all that uncommon for workshops to fit the cheapest brake pads they can find to a vehicle.
These cheaper brake pads are often made up of lower grade materials and can cause the vibrations in the brakes that cause squeal.
On top of this, brake rotors that are in poor condition or that haven’t been machined can greatly contribute to squeal as the edge of the new pad may catch the lip of the old rotor. This is one of the reasons we always recommend replacing pads and rotors at the same time.
3. Debris stuck in the brakes – This is a little less common but still up there with some of our favourite bothersome squeals, rocks or debris getting caught in the brakes themselves.
As the brake rotor rotates past whatever is caught in there, the brakes can squeal and squeak horribly. This is often more common for 4wd’s and offroad enthusiasts though and can even be caused by rust from not washing the car properly.
Thanks to Milton for requesting this blog post. If you have any suggestions for blog posts you'd like to see, follow the links below. While this isn’t every cause, it is a good show of some of the most common reasons for brakes to squeal.
If you have any questions about this blog post, would like a second opinion from a mechanic or would like to find an honest mechanic in Brisbane, check out Kashy here.