5 Most Common Causes of Brake Squeak

A squeaking noise from your car can be concerning if you don’t know what’s causing the noise.  If you only hear the squeaking noise when you are applying your brakes then that means there is likely a problem with your brake system causing the squeaking noise.

So what usually causes your brakes to squeak?  The most common causes of brake squeaks are worn brake pads, glazed brake rotors, or warped brake rotors.  Brake pads and brake rotors are meant to be replaced when they are worn out, so if you hear a squeaking noise when braking first check your brake pads and rotors for wear.

But how do you know if your brake pads or rotors are worn out?  Can you tell if your brake rotors and pads are worn out by just looking at them?  What other brake issues can cause squeaking when braking?  These questions answered and more.

1. Worn Brake Pads

The brake pads installed on your car will have a metal tab installed on them that is designed to alert you when your brake pad material gets too low, this tab is called a brake pad squealer.  When your brake pad material gets too low the brake pad squealer will come in contact with your brake rotor and will make a high pitched squeal or squeak sound.

Once your brake pad material gets low enough the squealing/squeaking sound will continue until the brake pads are replaced with new ones.  So if your car starts making squeaking or squealing noises when you brake one day out of the blue there is a chance that your brake pads are worn and need to be replaced.

If you know that your brake rotors are in good shape or have been recently replaced then your focus should be on your brake pads.  To tell if your brake pads need to be replaced check out my other article on how to tell if your brake pads are worn and need to be replaced.

2. Glazed Brake Rotors

Brake rotors can also become glazed if they are not broken in properly or are exposed to high heat situations.  When brake rotors become glazed the brake pads won’t be able to grip into the brake rotor as easily and can cause squeaking noises to occur while braking.

Sometimes the only solution for this issue is to have your brake rotors machined or resurfaced, you may also opt to just have them replaced.  Replacement brake rotors usually don’t cost an arm and a leg for brand new ones so you may want to go that route instead of having your old brake rotors resurfaced.

3. Brake Rotors Are Warped

Warped brake rotors can also cause your brakes to squeak when coming to a stop.  Brake rotors are designed to be round and flat on the surface, but excess heat can cause the brake rotors to become so hot that they actually warp.

When this happens your brake pads will touch the uneven surface of the brake rotor and squeak as it moves over the surface.  Unfortunately, the only real solution for warped brake rotors is to have them replaced, the good news is that most brake rotors are fairly inexpensive to replace on most vehicles.

4. Brake Pads Weren’t Broken In

Brake pads can also cause squeaking sounds if they are not broken in after they are installed.  If you don’t properly break in new brake pads it can cause the braking surface to become glazed over which also reduces braking power.   Since the brake pads are glazed over they will squeak as they come into contact with the brake rotor.

You can try to heavily brake a few times consecutively to see if your squeaking brake problem still persists.  Sometimes you are able to wear down the surface of a glazed brake pad this way, but sometimes the brake pads will need to be replaced with new ones.

To break in new brake pads accelerate to 30-40 MPH and then come to a stop quickly, repeat that procedure 4 to 5 times.  After that, the brake pads should be broken in and ready for normal use.

5. Brake Rotors Have Manufacturing Issues

Another cause for squeaking brakes is manufacturing issues with brake components.  You’d think that using new brake parts wouldn’t cause squeaking but that’s not always the case.  Sometimes brake parts will have defects from the manufacturing process that cause your brakes to squeak or squeal.

When I recently bought new replacement brake rotors and this happened to me, one of the brake rotors had a small defect around the lip of the brake rotor causing the brake rotor surface to be uneven and would cause squeaking when I would come to a stop.  I inspected the brake rotors and found the defect and then sanded down the area of the defect on the brake rotor to make it flat, which stopped the squeaking and vibration that I felt.

6. Squeaking Brake Caliper Piston and Brake Pad Backing Plate

Another common area for squeaks coming from your brakes is the area between the brake caliper piston and the brake pad backing plate.   If you did not know your brake calipers have a piston that applies pressure on the back of your brake pads which then applies pressure to the brake rotor with the front of the brake pad material.

Since the brake caliper piston and the back of the brake pad are both metal squeaks can occur from the metal on metal contact.  To get around this problem most brake pad manufacturers install an anti squeak material on the back of the brake pad to keep squeaks from happening but over time the anti squeak material can become brittle and fall off.

When this happens you will hear squeaking from the metal piston coming into contact with the metal backing plate.  You can try to fix this by applying an anti-squeal paste to the back of the brake pad plate to quiet the squeaking/squealing noise and that should help at least temporarily.  But you may need to replace your brake pads to fully fix the squeaking noise.

Related Questions

How do you know if your brake pads or rotors are worn out? 

If you are hearing a squeaking noise coming from your car when you brake you likely should have your brake system inspected, this is usually a sign that your brake pads are worn and need to be replaced, but it could be that both the brake rotor and pad need to be replaced.

The easiest way to tell if your brake pads are worn out is by inspecting the brake pad material to see how much brake pad material is remaining.  You may have to take your wheels off to be able to see behind the brake pad backing plate to see how much brake pad material is left.  If it looks like there is not much brake pad material left (less than 4mm) then your brake pads need to be replaced.

New brake rotors have a smooth surface so if your brake rotors have a bunch of etching and have a deep lip on the outer edge they likely need to be replaced.  Another sign that your brake rotors need to be replaced is a pulsing feeling when braking, if your brakes don’t feel smooth when coming to a stop it’s likely that your brake rotors are warped and need to be replaced with new smooth brake rotors.

Can you tell if your brake rotors and pads are worn out by just looking at them?

Both brake pads and brake rotors can be visually inspected to determine if they are worn out but it may be better to visually and physically inspect them to determine if they are worn out.  Sometimes you won’t be able to see how much brake pad material is left by just looking at the brake pad, you may have to remove your wheels to get a good look at the brake pad material.

With brake rotors, you may just be able to visually inspect the brake rotors to tell if they are worn but you may have to feel the rotor with your fingers to get an idea of how deep a lip is on the brake rotors.  Just don’t do this after you just got done driving as your brake rotors will be hot!