[fleetfoot]

While at the track last weekend, I noticed that my driver side brake caliper has developed a "creak". This is most noticeable at a stop if I apply more pressure or release the pedal. I removed the wheel and confirmed the noise is coming directly from the caliper. I removed the pads, springs, and pins, but didn't see anything unusual. The pistons moved smoothly when I pressed them back into the caliper with my fingers.

At this point I'm trying to decide if there's any risk from just living with the creak, or if it's a leading indicator of a bigger issue. Any suggestions?

A few more details:
1) I've got 25,000 miles and 30 track days on the car
2) The piston dust boots are cracked
3) The only potential next step I've come across is doing a caliper rebuild; I'm not sure if this is necessary.

[HP Autosport]

Originally Posted by fleetfoot

While at the track last weekend, I noticed that my driver side brake caliper has developed a "creak". This is most noticeable at a stop if I apply more pressure or release the pedal. I removed the wheel and confirmed the noise is coming directly from the caliper. I removed the pads, springs, and pins, but didn't see anything unusual. The pistons moved smoothly when I pressed them back into the caliper with my fingers.

At this point I'm trying to decide if there's any risk from just living with the creak, or if it's a leading indicator of a bigger issue. Any suggestions?

A few more details:
1) I've got 25,000 miles and 30 track days on the car
2) The piston dust boots are cracked
3) The only potential next step I've come across is doing a caliper rebuild; I'm not sure if this is necessary.

if no fluid leaks, piston not seized and no abnormal brake pad wear you are good to go.

Lube the guide pins and end of the pad backing plates and see if that does anything.

[fleetfoot]

Originally Posted by HP Autosport

if no fluid leaks, piston not seized and no abnormal brake pad wear you are good to go.

Lube the guide pins and end of the pad backing plates and see if that does anything.

I just went ahead and lubed these up, but no change. Any other ideas?

[HP Autosport]

Originally Posted by fleetfoot

I just went ahead and lubed these up, but no change. Any other ideas?

Something is flexing or moving. I think that is what you are hearing. What pads are on the car now? If race pads, does street pads eliminate the noise? Do you use any sort of paste on the backing plate against the piston and caliper? The noise the pads are typically a clunk or rattle, though.

[fleetfoot]

It definitely sounds like something flexing. Currently running PFC-08 pads with no paste.

[HP Autosport]

Originally Posted by fleetfoot

It definitely sounds like something flexing. Currently running PFC-08 pads with no paste.

Worth adding some paste to the contact points on the pad and see what happens.

[Ata_T1T]

What brake fluid are you running?

I JUST went through the same thing and a combination of these solved my problems:

Switched from ATE to SRF

Cleaned the brake caliper

Noise stopped.

[fleetfoot]

Originally Posted by Ata_T1T

What brake fluid are you running?

I JUST went through the same thing and a combination of these solved my problems:

Switched from ATE to SRF

Cleaned the brake caliper

Noise stopped.

I’m running RBF600. Any ideas why fluid would make a difference? I wonder if it was just the bleeding that somehow helped.

I did clean some of the caliper where the pads sit while I was in there lubing the guide pins yesterday. What part did you clean?

[Ata_T1T]

Originally Posted by fleetfoot

I’m running RBF600. Any ideas why fluid would make a difference? I wonder if it was just the bleeding that somehow helped.

I did clean some of the caliper where the pads sit while I was in there lubing the guide pins yesterday. What part did you clean?

I have a suspicision that it was because my ATE fluid was not LV rated. I'm not sure if RBF600 is low viscosity or not.

I took out the brake pad; cleaned the entire caliper and surrounding piston with brake clean and wiped it squeaky clean.

It could be a combination of fluid, bleeding and cleaning.

[fleetfoot]

I tightened the caliper bolts and bled the fluid yesterday, but still the same noise. I got my ear closer to the caliper while having a friend press the brake and it seems to be coming from the inboard pistons. If this were a street car I wouldn’t worry, but with it going on track I think my only smart option at this point is to do a caliper rebuild. Now where to have that done in the Atlanta area?

• I called Solo Motorsport and they said they hadn’t done many rebuilds, so I don’t want them learning on mine.
• I called Harrison Motorsport and the front desk guy said his shop foreman doesn’t like doing that work (aren’t you guys a race shop?!?). Eventually he provided a quote for $1300, with a claim of 5-7 hours of labor. Uhhh no thanks.
• I’m going to call Gran Turismo East Monday and see if this is in their wheelhouse. Even if it’s over $1000, I’d trust them more to do the job right based on past experiences.

Let me know if you’ve had a good rebuild experience anywhere else.

[HP Autosport]

Originally Posted by fleetfoot

I tightened the caliper bolts and bled the fluid yesterday, but still the same noise. I got my ear closer to the caliper while having a friend press the brake and it seems to be coming from the inboard pistons. If this were a street car I wouldn’t worry, but with it going on track I think my only smart option at this point is to do a caliper rebuild. Now where to have that done in the Atlanta area?

• I called Solo Motorsport and they said they hadn’t done many rebuilds, so I don’t want them learning on mine.
• I called Harrison Motorsport and the front desk guy said his shop foreman doesn’t like doing that work (aren’t you guys a race shop?!?). Eventually he provided a quote for $1300, with a claim of 5-7 hours of labor. Uhhh no thanks.
• I’m going to call Gran Turismo East Monday and see if this is in their wheelhouse. Even if it’s over $1000, I’d trust them more to do the job right based on past experiences.

Let me know if you’ve had a good rebuild experience anywhere else.

Most shops don't rebuild OE style calipers these days because of OEM parts availability. Have you looked into a BMW replacement calipers?

[fleetfoot]

A BMW replacement caliper would be ~$1000. I hate to throw away relatively good calipers (and then my left one would be blue and my right one green haha). A rebuild of both front calipers for $750-1000 would be ideal.

[David.m]

If going to re-build the oem caliper and you track this kit might be worth considering and if you're handy there is plenty of info/guidance available for diy. Found this kit on the F80/82 forum.

https://racingbrake.com/bb-43bsp/

[fleetfoot]

I'll give that RB kit a look. I did some more research last night and found this same creaking problem on other brembo-style calipers for Audi, Subaru, and Lotus guys. This Lotus thread was the only one that seemed to solve the problem, which seemed to be excessive buildup of pad material between the piston and pads. He also added some anti-seize to the pads. I'm going to take the pads out again this weekend and give those specific surface a better cleaning. Fingers crossed!

FYI this Audi video perfectly captures the sound my car makes:

[fleetfoot]

Figured out the root cause today. It’s definitely the piston. Took the pads out and pressed each piston individually this time. The bottom inboard one won’t budge by hand, but would move with my spreader tool. And the pad is 1mm shallower there.

So looks like I’m gonna have to do a rebuild. How many hours of labor would you expect to pay for a job like that? Debating doing it myself.

[fleetfoot]

Finally convinced my usual shop, Bavarian Repair in Woodstock, to do the work. They’re estimating 6 hours of labor, which seems reasonable.

FWIW I called Harrison Motorsport for a quote twice and they never called back after saying they would send me a written quote. GTE said they wouldn’t do caliper rebuilds. Solo Motorsports Roswell said they would provide a callback quote, but never did. 🤷‍♂️ This is why I keep using Bavarian Repair.