[Noh Wan]

Hi all, wondering if anyone has any experience with this. I've searched but can't find anything about brake noises (other than squeal).

After my commute to/from work I back my car into it's parking spot. The first time I touch the brakes in reverse I hear a noticable clunk (in the rear I think). It doesn't repeat if I brake a second time and it doesn't clunk again if I pull forward and brake or back up a second time. It only seems to happen after a sustained drive. It's not loud enough to startle you, but it's clear as day. Sounds about the same as if a medium rock got stuck in a tire tread and came out into the wheel well at 30-40MPH (if that helps).

Full disclosure, I swapped in Pagid RSL 29 brake pads a couple of weeks ago for some extended track time and that marked the beginning of the noise. I assumed I had messed something up so I double checked everything, but Everything seems ok. Pedal is firm and consistent, braking is linear and doesn't pull even under hard track use.

I've removed both rear wheels and checked that everything seems tight. Pads seem to have even wear, pins are fully seated, rotors and calipers don't seem to have any excess play. I didn't notice any excessive play in any suspension components. That's not to say it doesn't exist, just that I couldn't find it on a cursory examination.

It doesn't seem like knock-back or pad tilt. Could it be the result of the different geometry on the backing plate? Anyone else have experience with the RSL 29's or experience this noise before? I have an appointment to get a couple of tires replaced tomorrow and will have them check it out, but I can't repeat the noise reliably.

Thanks in advance!

[ZL9M2]

Common with aftermarket pads. Some movement of the pad in the caliper when changing directions.

[Up4speed]

I have a 2015 GTI that I use on the track, and put aftermarket pads on. They do the same thing. The backing of the plate is probably a TINY bit smaller than stock, causing the to shift ever so slightly and cause a knock. It can be a little annoying, but won't cause any issues. As the brake dust builds up, they seem to get quiet, then if I wash the car, they start to knock again, lol

[dtran556]

could it be possible that something is making your brakes wet while you are working? i get the same clunking noise as you after a car wash and i pull my car back into the garage after each wash

[Noh Wan]

Thanks everyone! I'm glad to hear it's not unusual for the aftermarket pads.

[ypk]

Can confirm, just switched to ME20s as well. Same "clunk" when changing direction. Never heard it being any issue other than that.

[Maynard]

Factory pads (rear) have a backing plate that adds about a mm to width; most aftermarkets do not have this, so they knock fore/aft when you change direction. You can pull the plate from yr stock pads and put it on the aftermarkets (at least w/ the Ferodo's I run).

[///MPhatic]

I just switched to the CarboTech 521's and immediately noticed this. I had not heard of it before, but some basic research turned up that it's a super common issue, usually on the rear only. I had my wife listen to me drive forwards and backwards several times and she confirmed it was just the rears. Apparently the shops know to remove the rear Brembo pad shim and install it on the aftermarket pads. I did this and will swap them on today.

I looked for a YouTube tutorial on how to remove the Brembo shim, but there wasn't any, so I made my own that I'll post later. It's simple really.

1. Heat the back of the pad up with a heat gun until it's warm to the touch.
2. Use a box knife on both sides to release the adhesive enough to get a small screwdriver in between the pad and shim.
3. Stick the screwdriver in at various spots until it pops off.
4. Use an eraser wheel (by hand) to rub the excess adhesive off of the shim.

Ignore the larger screwdriver and putty knife in the first pic, you won't need them.

[///MPhatic]

Just installed the shims. Such an easy job when you have a clean car, clean work area, and the right tools. That little Brembo pin punch is fantastic, and so is the pad spreader. Such a far cry from doing brake work 25 years ago!

[butraymond]

It's common on racing pad. When in high temperature situation, it has room to expand.

[Poochie]

In most of the vehicles I've own and repaired for friends and relatives, I never really had a positive experience with aftermarket brake pads or rotors. I always encountered various installations or performance issues (i.e. noises), it was almost never smooth sailing as the OEM offerings.

Long story short, unless it's absolutely necessary for track runs, stick with the OEM brake components - you'll thank me later..

[///MPhatic]

Originally Posted by Poochie

In most of the vehicles I've own and repaired for friends and relatives, I never really had a positive experience with aftermarket brake pads or rotors. I always encountered various installations or performance issues (i.e. noises), it was almost never smooth sailing as the OEM offerings.

Long story short, unless it's absolutely necessary for track runs, stick with the OEM brake components - you'll thank me later..

In my experience that's generally good advice, but really depends on the company you're using. I've used many, and had some bad experiences, but in pads have had great luck with G-Loc, Akebono, and I like these CarboTech pads as well (they use BMW blanks for their pads).

As far as rotors, same story, there are bad ones for sure, but there are also vastly better choices than stock (at a cost).

BMW themselves don't make rotors or pads as I understand it, so sourcing them elsewhere is just doing what they did, only being more specific to your own needs.

[chris719]

Originally Posted by ///MPhatic

In my experience that's generally good advice, but really depends on the company you're using. I've used many, and had some bad experiences, but in pads have had great luck with G-Loc, Akebono, and I like these CarboTech pads as well (they use BMW blanks for their pads).

As far as rotors, same story, there are bad ones for sure, but there are also vastly better choices than stock (at a cost).

BMW themselves don't make rotors or pads as I understand it, so sourcing them elsewhere is just doing what they did, only being more specific to your own needs.

Really appreciate the pictures and post!

Very interested on your feedback when you get some miles on the 1521s, especially regarding bite. As I'm sure you know, the stock 2NH pads are insanely dusty, like 3x any other BMW pads. The bite is too much when warm also IMO.

I was ready to go buy some CT 1521 but have seen some posts on other forums that say the initial bite is not good in the cold/wet, and I had some scary experiences with Hawk pads that did this on my Mazda 3. Perhaps the overboosted pedal and drilled rotors will help this on the M2C though.

[///MPhatic]

Originally Posted by chris719

Really appreciate the pictures and post!

Very interested on your feedback when you get some miles on the 1521s, especially regarding bite. As I'm sure you know, the stock 2NH pads are insanely dusty, like 3x any other BMW pads. The bite is too much when warm also IMO.

I was ready to go buy some CT 1521 but have seen some posts on other forums that say the initial bite is not good in the cold/wet, and I had some scary experiences with Hawk pads that did this on my Mazda 3. Perhaps the overboosted pedal and drilled rotors will help this on the M2C though.

I'm happy to help in any way I can, but I'm not a good one to ask about performance because I never track my car. I can tell you this, though, they are definitely more capable pads than the Akebono street pads I had on the blue brakes. So far the 1521's feel a lot like the stock pad but with a lot less dust and no squealing. I'm told that they are super easy on rotors as well, but that has yet to be seen.

I wish G-Loc made pads for the 2NH, as they are my absolute favorites. I've had RedStuff's, which were ok, and the Akebono's (that only polish the rotors). I'll know more after some more miles and will definitely give my street thoughts.

[beezyM2C]

im running RSL 29s as well. Have the clunk and massive squeal as well. Im daily/streeting GIROS with RSLs in the front stock rotors RSLs in back upgraded lines etc etc

[doughboy]

Originally Posted by beezyM2C

im running RSL 29s as well. Have the clunk and massive squeal as well. Im daily/streeting GIROS with RSLs in the front stock rotors RSLs in back upgraded lines etc etc

Rs29 are way OTT for DD / street. They're an endurance racing pad. They won't get clean or hot enough..

Stock will do fine.