Grinding Noises When Braking?

Today’s cars are sophisticated pieces of equipment. A typical entry-level car has more technology and computing power than NASA needed to land astronauts on the moon. The idea of getting under the hood or otherwise getting dirt under your fingernails might not be your cup of tea, and can even be intimidating, but there’s value to being able to identify and diagnose an issue before driving over to your next service appointment. 

How do disc brakes work?

Modern disc brakes are actually pretty straightforward in concept, even if there are a lot of parts involved. The good news is, if you’re hearing a grinding noise when you’re braking, we can probably narrow the scope of where we need to look to diagnose the issue.

There are several parts that matter here. Brake lines bring pressurized fluid to the brake caliper. The caliper holds and actuates the brake pads, pressing up against the surface of the rotor to slow and, eventually, stop your car.

Brake pads are constructed with a high-friction material applied to a metal backing plate. It is a fact of life, and a result of the work they do, that brake pads wear down over time. The rotors also are subject to wear, and either part might be the cause of some alarming sounds.

Why are my brakes so loud?

There are a few different causes that might lead to various sounds you never want to hear.

Grinding noises: Excessive brake pad wear

Excessive wear on your brake pads is the single most common cause of grinding noises when braking. As the high-friction material wears down, you are left with only the metal backing plate of your brake pad, leading to “metal-on-metal” as the worn-down brake pad squeezes the metal disc brake rotor.

This isn’t just a minor inconvenience, either—the backing plate of your brake pad can eat into the rotor, causing grooves and potentially serious (and costly!) damage. It’s also possible that caliper is coming into contact with the rotor, which can serious damage to either or both the rotor and caliper, leading to more costly parts and labor to repair what could’ve been a relatively minor and standard bit of standard vehicle maintenance.

Constant scraping noises: Debris lodged in brakes

A pebble, a stick, a bit of road debris—it’s incredible what can find its way into a supposedly closed system. Typically, the debris becomes stuck between the caliper and the rotor, which can cause damage to either part. If you hear the grinding noise whenever your car is in motion, and not just when you’re braking, this is the likely explanation.

Grinding noises after replacing your brake pads: Low-quality parts

If you recently had your brakes serviced and your brake pads replaced and soon after starting to notice a grinding noise when you brake, it’s possible that your mechanic selected low-quality replacement parts. Semi-metallic pads might contain larger inclusions of hard metals that can eat into the rotors, causing the grinding noises, along with hundreds of dollars more in damage. You can avoid this issue by selecting OEM brake pads.

That’s a squeal, not a grind: Regular wear on your brake pads

It can be hard to distinguish between the two noises, but if what you hear is more of a squeal than a grinding noise, odds are it’s a sign that it’s time to replace your brake pads. OEM brake pads are designed with a wear indicator that will create a squealing noise but not damage your rotors. This is a convenience feature to alert you that your pads are wearing down and due for replacement.

Whatever the reason, a grinding noise when you’re braking is not something you should ignore. There are a handful of potential causes, and most of them will have similar fixes. Knowing the issue will let you shop for the appropriate parts—and Bernardi Parts Volvo carries all of the OEM parts and accessories you’ll need, whatever the project.