Stop Tech Slotted 380/365 Street Pad "Squeal"

[Longboarder]

Gentlemen,

I picked up a bone stock 2012 e92 M3 a year and a half ago with the intention of tracking it. Bought a new Stop Tech 380/365 slotted kit with street performance pads and got some Cup2's, camber plates and an alignment. Well it made it to two track events but with life changes I'm now using it as a daily driver and utility car so it doesn't see track use.

I like the brakes and want to keep them except they squeak and squeal all the time. When this happens I usually do a bed-in but that only seems to work for a couple days and the squeals return. The original pads have 80% remaining but I'm thinking maybe I glazed them a little at the track or something. Went to Thermal it was over 100 degrees F and the car was pushed hard. I know they shouldn't squeal because I had this kit / pads before on a previous e92 for 30,000 miles.

You guys with Stop Techs + street performance pads encounter something similar? If the pads were causing squeal is it going to be noticeable by looking at the pads?

Cheers.

[EJT86]

I’ve never had that problem. Did you wash the rotors before you installed them? They have an anti corrosive coating that needs to be removed by washing or brake clean. I’m guessing they’re not zinc since you’re in CA did you grease everything up? Just a couple things to consider. Maybe get the wheels off grease up the calipers then swap the pads around (inside to outside) and try a bed in again

[Longboarder]

Originally Posted by EJT86

I’ve never had that problem. Did you wash the rotors before you installed them? They have an anti corrosive coating that needs to be removed by washing or brake clean. I’m guessing they’re not zinc since you’re in CA did you grease everything up? Just a couple things to consider. Maybe get the wheels off grease up the calipers then swap the pads around (inside to outside) and try a bed in again

Hi yes installation was done by the same shop that installed the same kit on my prior M3 (which didnt squeal with 30k miles and lots of track use). On my current M3, the brakes were greased once after my Thermal track day last year and that helped in getting rid of the squeal but the squeal keeps returning. That's why I think I might have done something to the pads but dunno. Even if I removed the pads I wouldn't know what I'm looking for.

[EJT86]

Originally Posted by Longboarder

Hi yes installation was done by the same shop that installed the same kit on my prior M3 (which didnt squeal with 30k miles and lots of track use). On my current M3, the brakes were greased once after my Thermal track day last year and that helped in getting rid of the squeal but the squeal keeps returning. That's why I think I might have done something to the pads but dunno. Even if I removed the pads I wouldn't know what I'm looking for.

Then I would try using an Emory cloth on the rotors and pads, and swap the inside pads with the outside ones

[Richbot]

Have you tried getting them warm, spraying them with water, and letting them rust up overnight and then driving again? That surface rust becomes an abrasive when you next apply the brakes and can be helpful for removing thin layers of crud and has helped to get rid of a pedal pulse a couple times for me in the past. A squeal is just a really high frequency vibration - might be worth a shot?

I had the street performance pads on my STR40 front kit for like 55k miles and there was always a very occasional squeak here and there but never constanst squeal. But I also never pushed them so hard that they faded badly on track. The squeaks did get worse the thinner the pads get, which makes sense, less mass damping the vibrations. Are they about worn out already? If tracked hard I've heard they wear pretty fast.

[Longboarder]

Originally Posted by Richbot

Have you tried getting them warm, spraying them with water, and letting them rust up overnight and then driving again? That surface rust becomes an abrasive when you next apply the brakes and can be helpful for removing thin layers of crud

Wow haven't heard that approach before but will give it a shot!

I contacted my shop since I need an oil change and they will inspect the pads and scuff them but if I cooked them at the track I suppose I need new pads.

[dparm]

Try a Flex-Hone tool on the rotors. You can get them on Amazon.

Performance pads make noise, that's just the reality of it. Why don't you just run a cheap ceramic street pad around town and then throw a track pad on? Changes on those calipers are pretty easy.

[Deebo]

I had the same issue using the supplied pads on the Stoptech kit, albeit the smaller one on my old 335. I swapped to Akebono ceramic pads and got rid of the squealing, plus almost never needed to clean the wheels.

[Longboarder]

Well now I know why it was making an awful noise:

[Richbot]

Sweet flame job

[Longboarder]

Originally Posted by Richbot

Sweet flame job

ever seen this before? looks like a rock got in there but no because the rotor is fine.

[Ximian]

Originally Posted by Longboarder

ever seen this before? looks like a rock got in there but no because the rotor is fine.

Could be a manufacturing defect, damage during installation, or more likely, caused by some object like a rock. If your rotors have slots or holes, the object could have gone in them without leaving behind any damage on the rotors.

[EJT86]

Originally Posted by Longboarder

ever seen this before? looks like a rock got in there but no because the rotor is fine.

My rear pad has that. No squeal I just had this unwiped ring form on the rotor took it apart and found a gouge like that. Swapped it to the inside so at least the new ring that’s probably formed isn’t visible anymore