Brake "clap/clunk" sound?

[BimmerNugget]

My E90 M3 has been making some funny sounds lately.

When I brake, there is a "clap/clunk" sound coming from the front brakes. It almost sounds like the brake pad is loose inside the caliper or something.

Happens 5-6/10 times I hit the brakes. Even happens at low speeds like parking lot maneuvers or stop signs.

The brake rotors and pads were replaced 7,000 miles ago with OE parts at a reputable BMW Indy (German Auto Group) so I'm sure they are still good. The clunk started happening around 2,000 miles ago, so the first 5,000 miles were good.

I visually inspected the pads/rotors/calipers/ and retainer clips and they all seem good and in the right place.

Any idea where to look next?

[BimmerNugget]

Forgot to mention, there is only 1 clap/clunk per braking. It will clap/clunk again the next time I apply the brakes at the next stop sign or whatever...

[apexscholar]

If the visual inspection yielded nothing I would dive into taking the braking system apart and seeing if there is anything that could have been damaged during install. Make sure everything is torqued properly and double check everything is installed as it should be.

[wootloops]

Both of my BMWs do it. It usually happens the first time you hit the brakes after changing directions. When I back out of my garage, I get one CLUNK and then when I move forward and hit the first top sign I hear another CLUNK. Assuming its the same pad noise, it's probably nothing to worry about.

[tdott]

Loose pads.

See if they didn't put the shims back in or if the pads are just too loose.

[BimmerNugget]

Originally Posted by tdott

Loose pads.

See if they didn't put the shims back in or if the pads are just too loose.

Yeah it sounds like loose pads. What are the shims? I see the retainer clips are on the calipers. Not sure what shims are?

[tdott]

Originally Posted by BimmerNugget

Yeah it sounds like loose pads. What are the shims? I see the retainer clips are on the calipers. Not sure what shims are?

Actually yea no shims on stock calipers, so they must just be loose, inspect your caliper brackets to see if they are worn down where the pads make contact or maybe it is just the pad tolerances aren't good. Try a different brand see if they fit better.

I have f8x brakes and they have an anti rattle clip that I was thinking of.

[spammysammich]

While I don't notice it on my M3 brembos, aftermarket pads in my STI brembos click when changing forward and backward direction. the pads are shifting in the pocket. Silicone grease or high temp anti squeal grease on the back of the pads and on points where they contact the caliper quiets it for a bit. I don't sweat it anymore as guide pins and caliper don't seem to be wearing or impacted by the shift. Perhaps if I tracked the car, I would try to shim it better.

[ksc]

I have this on my front passenger brake. Going to try fixing it and inspecting the pads. Any consensus on what fixes it? I have new rotors and pads, guide pins are tight. Sound was present before the new brake refresh, and is still present after.

[Remonster]

Originally Posted by BimmerNugget

My E90 M3 has been making some funny sounds lately.

When I brake, there is a "clap/clunk" sound coming from the front brakes. It almost sounds like the brake pad is loose inside the caliper or something.

Happens 5-6/10 times I hit the brakes. Even happens at low speeds like parking lot maneuvers or stop signs.

The brake rotors and pads were replaced 7,000 miles ago with OE parts at a reputable BMW Indy (German Auto Group) so I'm sure they are still good. The clunk started happening around 2,000 miles ago, so the first 5,000 miles were good.

I visually inspected the pads/rotors/calipers/ and retainer clips and they all seem good and in the right place.

Any idea where to look next?

I will almost guarantee that the shop put in OE or OE-quality brake pads but not the actual genuine BMW part. It's very common for pads to be listed as OE replacement because they will fit into the caliper but may be fractionally smaller than the genuine part. This allows the pad to move a bit and you'll hear it slap against the caliper.

This is almost always noticeable with track pads, they're smaller on purpose to create room for thermal expansion when you're beating on them.

If this is the cause of the noise you're hearing, it won't cause any kind of problem but it won't get any less annoying. The fix would be a different pad that's hopefully a bit larger. I'd do the actual genuine parts to avoid guess work.