Carbotech brake pad fitment issues on Model 3 Performance

[comp3mo]

Has anyone else had fitment issues with Carbotech brake pads on the Model 3 Performance?

I have a 2021 M3P (Fremont factory, July 2021 build date) and purchased Carbotech AX6 front and rear pads through Martian Wheels. The brake pad part numbers that I received are correct (CT83752FP-AX6 / CT83752RP-AX6), but there are fitment issues on both the front and rear. My local shop here in Fremont, California helped install the pads.

The front pads make loud clunking noises the first time I brake after changing directions. Reverse out of a parking spot and brake "clunk", shift into drive and brake "clunk". Basically it seems like the front pads have some room to move around inside of the calipers.

The rear pads would not fit into the calipers at all. We had to re-install the stock rear brake pads for now. First, the narrow portions at the end of the backing plates were too wide by around 1mm. We ground those down to fit inside of the calipers, but then found out these pads are at least 1.5mm thicker than the stock pads. Even with the pistons fully pushed back, there was not enough room between the pads to fit the brake rotor.

Has anyone else encountered these problems? Could the brake calipers have changed to a new design recently?

 

[Theadonnan]

Did you reach out to carbotech?

 

[comp3mo]

Did you reach out to carbotech?

I have reached out to both Carbotech and Martian Wheels. I'll keep this thread updated with their replies!

 

[MasterC17]

I mean aftermarket pads are always going to be noisier than stock pads, especially Carbotech's which are the loudest pads on earth (in my experience).

The rears are a tight, press fit in my experience, but they fit. Are you sure the piston was retracted all the way? You need to use a 9V battery or equivalent to spin back the EPB all the way.

FWIW, the rear calipers HAVE been slightly redesigned in the last ~six months or so, but I do not believe the pad fitment would have been affected.

 

[tm1v2]

I recall some clunking noises from a looser fit for Carbotechs in past cars I've owned where I used Carbotechs. In those cars it was normal/expected/typical, the Carbotech pad backing was just a little smaller than OEM. However it does sound like your front pads are much looser (much worse clunking) than what I experienced in those other cars, so I think you're right to bring this up as an issue to Carbotech and/or your vendor. (And obviously so for the rear pads that are too big and don't fit at all.)

As for Carbotech track pads, I loved whichever ones I was using ~ 10 years ago, unbedded noise and all. Was probably XP10 or XP12, it was a <= 3400 lbs car with ~ 350 crank hp, definitely less demanding than an M3P. I had tried one highly recommend street+track compromise pad (not a Carbotech) and it was terrible at both, so after that I said f*** it, I'll just swap pads for track days. The Carbotech XP were just fantastic in that car (it did have nice Brembo calipers and very good EBD+ADS), I could hammer on them all I wanted on 25-30 minute track sessions, never a hint of fade, and that was without any ducting. (To be fair, I never truly pushed the absolute limits of late braking. It was my daily driver and only car, and I wasn't racing.)

The thing with the XPs is they're truly meant to be track-only. They stop just fine at cold/street temps, however they won't stay bedded with street driving, they'll eventually scrape off any bedded material and then become HOLY LORD ALMIGHTY LOUD and sound like 20 school buses all screeching to a halt at once, with just a light application of the brake pedal.

I actually found that behavior highly useful though! My routine was:
1) A few days before track day, install the XPs along with any other pre track day prep (e.g. any fluid changes needed).
2) Use pre-track driving to scrape off street pad material - the XPs did that great when cold / street temps. You know this step is done when they get super loud.
3) Don't even worry about bedding them before getting on the track, that happened naturally on the first session.
4) After the track day they would be totally quiet - because they're bedded!
5) When not going back to the track for a while, just keep driving on the XPs until they start to screech bloody murder again. Then you know you're done unbedding them and ready to swap back to your street pads.

Btw I am familiar with the 1521 street pads where Carbotech says you don't need to re-bed when swapping between them and XPs. I tried the 1521s and on that car, I actually found them to be a downgrade vs its stock pads for its Brembos. Since re-bedding was super easy with the XPs, I decided to just keep using the OEM pads for street.

 

[KenATKNS]

Hi - I was invited/linked by a friend and I have experience w/ Carbotech pads.

For fixed calipers, if the pads are a bit narrow there can be the aforementioned clunk when braking in opposite directions. The anti-rattle hardware and retaining pins can also make noise as the pad shifts back and forth.

It should not be a safety issue unless the pad was grossly too narrow but on a street car (and one that I'd guess is quieter!) it would be pretty annoying. The tolerance on the pad width is not super critical but it is a thing. Race pads can rattle all the time - not really a big deal if that makes sense.

In the rear - unless there is something I have not seen it should not be a press fit. The pad needs to drop in pretty nicely and not bind on the caliper abutment plates/inner body.

If you do need more help w/ Carbotech on this issue feel free to reach out.

Ken

 

[Motion122]

Has anyone else had fitment issues with Carbotech brake pads on the Model 3 Performance?

I have a 2021 M3P (Fremont factory, July 2021 build date) and purchased Carbotech AX6 front and rear pads through Martian Wheels. The brake pad part numbers that I received are correct (CT83752FP-AX6 / CT83752RP-AX6), but there are fitment issues on both the front and rear. My local shop here in Fremont, California helped install the pads.

The front pads make loud clunking noises the first time I brake after changing directions. Reverse out of a parking spot and brake "clunk", shift into drive and brake "clunk". Basically it seems like the front pads have some room to move around inside of the calipers.

The rear pads would not fit into the calipers at all. We had to re-install the stock rear brake pads for now. First, the narrow portions at the end of the backing plates were too wide by around 1mm. We ground those down to fit inside of the calipers, but then found out these pads are at least 1.5mm thicker than the stock pads. Even with the pistons fully pushed back, there was not enough room between the pads to fit the brake rotor.

Has anyone else encountered these problems? Could the brake calipers have changed to a new design recently?

Pad clunk is very typical of aftermarket race/track pads because of the lack of shims.

 

[comp3mo]

I finally had time to jack up my car and check the rear Carbotech AX6 brake pad fitment for myself instead of heading back to my local tuning shop.

For the brake pad thickness concern, @MasterC17 was correct that the electronic parking brake (EPB) was not fully retracted. My shop simply put the car into Tow Mode and then disconnected the wire going into the EPB. I ordered the Tevo Solutions EPB service cable (Tesla Model 3 EPB service cable) and was able to get the pistons fully retracted. The keying on the cable did not match the connector on my EPB, but I was able to pull out the black plastic keying insert from the service cable to make it work. I've contacted Tevo Solutions about this.

For the brake pad ear width issue, I confirmed it is a problem on my car. The Carbotech backing plate ears are 19mm wide, and they definitely need to be grinded down to 18mm in order to fit into the red calipers for the outside brake pads (the OEM brake pad ears are even narrower, maybe 17mm). No modifications need to be made for the inside brake pads that get held in by spring clips (as mentioned by other members here, it's a very tight fit but manageable).

I reached out to Carbotech using their website contact form but never heard back.

Drew from Martian Wheels was very responsive. He confirmed that various compounds of Carbotech pads they've used in their M3P all had 19mm ears and were a snug fit but worked great.

I don't know if the rear brake caliper re-design that happened in the last 6 months mentioned by @MasterC17 affected brake pad fitment, but the Carbotech pads with 19mm ears definitely will not fit into my outside rear calipers without grinding them down to 18mm.

 

[comp3mo]

Just a final update. I headed back to my local tuning shop this past week and confirmed that all of the front bolts were torqued down correctly. The clunking sound from the front appears to be from the brake pads. To me it looks like the front brake pads are always self-centering because they are held in place with pins and spring clips, but we could not find anything loose so we're concluding that it's the pads.

For the recent rear M3P brake caliper re-design, it looks like the entire rear brake assembly was painted red for earlier model years. My 2021 M3P only has the rear outside brake caliper painted red while the inside caliper (that holds the piston and EPB) is black. I don't know if the re-design only changed the inside caliper color to black or also changed the outside caliper brake pad fitment.

 

[MountainPass]

Just a final update. I headed back to my local tuning shop this past week and confirmed that all of the front bolts were torqued down correctly. The clunking sound from the front appears to be from the brake pads. To me it looks like the front brake pads are always self-centering because they are held in place with pins and spring clips, but we could not find anything loose so we're concluding that it's the pads.

For the recent rear M3P brake caliper re-design, it looks like the entire rear brake assembly was painted red for earlier model years. My 2021 M3P only has the rear outside brake caliper painted red while the inside caliper (that holds the piston and EPB) is black. I don't know if the re-design only changed the inside caliper color to black or also changed the outside caliper brake pad fitment.

If the pads aren't a perfect fit they will clunk when you change direction then press the brakes again. It is very good that you confirmed it wasn't anything loose though!

 

[Motion122]

Just a final update. I headed back to my local tuning shop this past week and confirmed that all of the front bolts were torqued down correctly. The clunking sound from the front appears to be from the brake pads. To me it looks like the front brake pads are always self-centering because they are held in place with pins and spring clips, but we could not find anything loose so we're concluding that it's the pads.

For the recent rear M3P brake caliper re-design, it looks like the entire rear brake assembly was painted red for earlier model years. My 2021 M3P only has the rear outside brake caliper painted red while the inside caliper (that holds the piston and EPB) is black. I don't know if the re-design only changed the inside caliper color to black or also changed the outside caliper brake pad fitment.

Even Pagid RS/RSL and Fedrodo track pads make similar sounds when the vehicle is changing directions. Maybe one of noisy pads you have to live with.

 

[K44ENT]

My December 2020 Model 3 performance makes this noise with standard brakes. It didn't do it when new but 5000 miles in and it's started.

 

[MasterC17]

My December 2020 Model 3 performance makes this noise with standard brakes. It didn't do it when new but 5000 miles in and it's started.

What the OP is reporting is a different concern due to aftermarket pads. Your brake noise can almost certainly be attributed to corrosion buildup on the rotor surfaces. Take the car for some spirited driving and work the brakes aggressively to clean it up.

 

[Motion122]

What the OP is reporting is a different concern due to aftermarket pads. Your brake noise can almost certainly be attributed to corrosion buildup on the rotor surfaces. Take the car for some spirited driving and work the brakes aggressively to clean it up.

Not a fitment or clunking issue?

 

[K44ENT]

What the OP is reporting is a different concern due to aftermarket pads. Your brake noise can almost certainly be attributed to corrosion buildup on the rotor surfaces. Take the car for some spirited driving and work the brakes aggressively to clean it up.

No it's a definite metallic clunking noise front one side on the front. Drive forward slowly and brake, it clunks, drive forward again and brake, the clunk is gone. Reverse and brake, it clunks, reverse again and no clunk. However if I drive forward again it will clunk. I'm sure corrosion has a small part to play but the rotor surface look clean and shiny. I think a pad is slightly sticking and the retaining spring is not strong enough to centre the pad, that and the pad is maybe slightly loose (under size). If I go for a drive and use the brakes to add some heat the heat expansion and maybe lack of corrosion stops the noise. All the other brakes are silent, just one on the front. I still think the root cause is a pad that is very slightly smaller than the others.

 

[Motion122]

No it's a definite metallic clunking noise front one side on the front. Drive forward slowly and brake, it clunks, drive forward again and brake, the clunk is gone. Reverse and brake, it clunks, reverse again and no clunk. However if I drive forward again it will clunk. I'm sure corrosion has a small part to play but the rotor surface look clean and shiny. I think a pad is slightly sticking and the retaining spring is not strong enough to centre the pad, that and the pad is maybe slightly loose (under size). If I go for a drive and use the brakes to add some heat the heat expansion and maybe lack of corrosion stops the noise. All the other brakes are silent, just one on the front. I still think the root cause is a pad that is very slightly smaller than the others.

The clunk has nothing to do with the bed-in process. If you can transfer the shim, that may reduce or eliminate the noise completely. The spring clip you are referring to may not have enough tension in the directions you wanted to reduce pad shifting. If you search on other vehicle forums, the pad clunking when changing direction has been discussed in depth. You are just trading off a bit of noise for brake performance.

 

[Scubadoo]

What the OP is reporting is a different concern due to aftermarket pads. Your brake noise can almost certainly be attributed to corrosion buildup on the rotor surfaces. Take the car for some spirited driving and work the brakes aggressively to clean it up.

Not necessarily corrosion. My M3LR started after about 7k miles. First application of brakes after direction change results in loud metallic clack. Holding the brake and applying forward then reverse drive power results in similar. Seems to be pads moving. On stock pads, very very clean 2022 M3LR, certainly zero corrosion.