M2 Brake Issue

nkwrite · 05-04-2018, 09:44 PM

I tracked my M2 at Watkins Glen and the car was wonderful, however, I have a bad rumble when I step on the brake pedal now, and a groaning noise. Second time this has happened...I am told this could be from the rotors glazing? It did go away the first time, but this time seems much worse. Has anyone else experienced this? This is unacceptable for a car that is advertised as a track-ready car. Should not happen. Also, how do I cure the problem?

Bee Pee · 05-05-2018, 12:55 AM

Pad deposits after a track day - re-do brake pad bed in procedure should clean up the discs nicely.

nkwrite · 05-06-2018, 09:27 AM

Thanks! I'll give it a shot and report back.

boostm3 · 05-06-2018, 09:37 AM

Are you on stock pads?

pal · 05-06-2018, 01:47 PM

If you ran with stock pads and stability control, the material has likely broken down a bit (chunked) and cracked. This will normally give you the grinding noise later, likely exacerbated with drilled rotors. It’s not M2 or BMW specific. If you take the pads off, you will likely see physical evidence of this.

boostm3 · 05-06-2018, 01:51 PM

Quote:

Originally Posted by pal

If you ran with stock pads and stability control, the material has likely broken down a bit (chunked) and cracked. This will normally give you the grinding noise later, likely exacerbated with drilled rotors. It’s not M2 or BMW specific. If you take the pads off, you will likely see physical evidence of this.

Ive never known any stock bmw that didnt require a change of pads for track duty.

pal · 05-06-2018, 02:00 PM

Quote:

Originally Posted by boostm3

Ive never known any stock bmw that didnt require a change of pads for track duty.

Agreed. I have yet to see any street car that gets tracked extensively run stock pads. Even GT3s tend to run Pagids or some other track pad. Same goes for fluid.

M+M · 05-06-2018, 04:01 PM

very hard to get a pad that can cover road and track well. Especially if you are going hard at the track. All track pads will screech sooner or later on the road and become annoying in city driving. And then road pads aren't up to it for prolonged track use. You may be finding it worse this time because you are going faster with a bit more familiarity.

PackPride85 · 05-06-2018, 04:19 PM

Quote:

Originally Posted by M+M

very hard to get a pad that can cover road and track well. Especially if you are going hard at the track. All track pads will screech sooner or later on the road and become annoying in city driving. And then road pads aren't up to it for prolonged track use. You may be finding it worse this time because you are going faster with a bit more familiarity.

What are your thoughts on switching out pads but using the same rotors. Have heard differing opinions on this.

Franzino · 05-06-2018, 05:01 PM

Quote:

Originally Posted by PackPride85

What are your thoughts on switching out pads but using the same rotors. Have heard differing opinions on this.

Zero problems!

Franzino · 05-06-2018, 05:05 PM

Quote:

Originally Posted by nkwrite

This is unacceptable for a car that is advertised as a track-ready car. Should not happen.

You are wrong! If BMW would fit trackpads as standard....they would get massive amount of complaints about everybody driving on the street with noisy brakes. The M2 is a street car not a track-ready car. It's a street car that you can also drive on track...if you fit different brake pads. You can order the M perf pads from BMW or go aftermarket for a solution.

chief1richard · 05-06-2018, 08:29 PM

Quote:

Originally Posted by Franzino

You are wrong! If BMW would fit trackpads as standard....they would get massive amount of complaints about everybody driving on the street with noisy brakes. The M2 is a street car not a track-ready car. It's a street car that you can also drive on track...if you fit different brake pads. You can order the M perf pads from BMW or go aftermarket for a solution.

Just tracked my car with Pagid brake pads. The difference between OEM and Pagids is incredible. Well worth the $ spent for track pads.

PackPride85 · 05-06-2018, 09:23 PM

Quote:

Originally Posted by chief1richard

Just tracked my car with Pagid brake pads. The difference between OEM and Pagids is incredible. Well worth the $ spent for track pads.

Even the high end Porshe guys all swap their pads for the track....and most of them use Pagid R29s as well.

eeyang92 · 05-07-2018, 01:43 AM

I ran into the same issue with stock pads. I ended up purchasing rs29s to scrape off the old deposits + my next hdpe event. My new issue was that I ended up boiling the stock fluid with the new pads, so now I have Castrol srf.

M3 Adjuster · 05-07-2018, 02:13 AM

Quote:

Originally Posted by nkwrite

I tracked my M2 at Watkins Glen and the car was wonderful, however, I have a bad rumble when I step on the brake pedal now, and a groaning noise. Second time this has happened...I am told this could be from the rotors glazing? It did go away the first time, but this time seems much worse. Has anyone else experienced this? This is unacceptable for a car that is advertised as a track-ready car. Should not happen. Also, how do I cure the problem?

Pump your brakes bro! No need to sell the M2!
For me simply braking slightly worked within a few stops ..

Quote:

Originally Posted by Bee Pee

Pad deposits after a track day - re-do brake pad bed in procedure should clean up the discs nicely.

Quote:

Originally Posted by pal

If you ran with stock pads and stability control, the material has likely broken down a bit (chunked) and cracked. This will normally give you the grinding noise later, likely exacerbated with drilled rotors. It's not M2 or BMW specific. If you take the pads off, you will likely see physical evidence of this.

I was on track in my 1M and had this issue occur this weekend as well. I drove on track, decided to pack the stock wheels in the car and drive home on my track set. I didn't get far up the road and I slowed to stop at an intersection and got a crunching sound from the brakes pulling to a stop. This happened the next few times I braked so to mitigate it I simply used the brakes very lightly when coming to a stop. This yielded more squeak/squeal but less crunch.

After about 15 miles of highway driving with a few stops in towns it didn't occur the rest of the way home. I ran Performance friction full race pads.

I agree with the others above that you can try a re-bed as well. The issue definitely revolves around cross drilled rotors. These shred the pad to a degree causing small chunks to imbed in the holes of the drilled rotors. An odd size chunk of brake material in your rotor has the same effect as a rock against a backing plate.

Reversing a short distance and slamming on the brakes is a good way to eject a rock stuck against a backing place and disc by the way, and also might be something to try.

For decades, BMW eschewed cross drilled rotors in favor of solid discs and this was never an issue. Old school bimwads will recall that slotted rotors were very common on aftermarket rotors for track use. These also can suffer from pad material getting trapped in the slots as well.

M3 Adjuster · 05-07-2018, 02:39 AM

Quote:

Originally Posted by eeyang92

I ran into the same issue with stock pads. I ended up purchasing rs29s to scrape off the old deposits + my next hdpe event. My new issue was that I ended up boiling the stock fluid with the new pads, so now I have Castrol srf.

Castrol SRF rocks. If you have an issue with that fluid .. then this is a driver problem.

Braking less is faster !

PackPride85 · 05-07-2018, 09:48 AM

Quote:

Originally Posted by M3 Adjuster

Castrol SRF rocks. If you have an issue with that fluid .. then this is a driver problem.

Braking less is faster !

For those that have swapped brake fluid for track. I'm assuming you just keep that in when on the streets and will continue to flush with track fluid? Can't think of any reason why not but figured I'd ask.

M+M · 05-07-2018, 04:10 PM

Quote:

Originally Posted by PackPride85

What are your thoughts on switching out pads but using the same rotors. Have heard differing opinions on this.

You will get better braking performance and it will shorten the life of the rotors. How much will depend on how hard you go and how hot you get the rotors. For example 15min sessions or 30 min sessions? Road pads are more sacrificial - that's why they can leave deposits. Track pads are more aggressive compound.
If you get too much heat into the rotor with no cooling they won't stand the heat as well as a competition rotor. But is all a question of how hard you want to go - A few casual trackdays is ok - just try and see how it goes.

M+M · 05-07-2018, 04:14 PM

yep just switch to track fluid permanently. SRF expensive but much better for a dd car as it resists moisture better. there other threads talking about this.

Al1969 · 05-21-2018, 03:28 PM

Quote:

Originally Posted by nkwrite

I tracked my M2 at Watkins Glen and the car was wonderful, however, I have a bad rumble when I step on the brake pedal now, and a groaning noise. Second time this has happened...I am told this could be from the rotors glazing? It did go away the first time, but this time seems much worse. Has anyone else experienced this? This is unacceptable for a car that is advertised as a track-ready car. Should not happen. Also, how do I cure the problem?

Similar issue reported on french M2 forum, apparently disks holes must be cleaned with water or air and rumble should go away ...

M3 Adjuster · 05-22-2018, 01:29 AM

Quote:

Originally Posted by PackPride85

Quote:

Originally Posted by M3 Adjuster

Castrol SRF rocks. If you have an issue with that fluid .. then this is a driver problem.

Braking less is faster !

For those that have swapped brake fluid for track. I'm assuming you just keep that in when on the streets and will continue to flush with track fluid? Can't think of any reason why not but figured I'd ask.

Correct. Brake fluid that has a higher wet and/or dry boiling point is more effective. It's been awhile since I checked but Castrol SRF has some of the highest boiling points for both wet and dry situations. The major key for SRF is its boiling point when wet blows all others out of the water. If you don't know the difference between a wet and dry boiling point ... it's time for a homework assignment.

http://www.ctbrakes.com/brake-fluid.asp

Smiley1175 · 05-24-2018, 07:12 PM

I'm with the OP on this one. The standard pads BMW use are great for the road but shit anywhere else. I ran my Porsche on the track straight from the showroom and never had the issues I've had with BMW.

If you're still getting the grinding sound or vibrations, get the discs machined and swap pads.
Simple rule, don't ever bother with the BMW pads on the track, swap them before going out along with better fluid.

05-04-2018, 09:44 PM	#1
nkwrite Registered 3 Rep 2 Posts Drives: 2017 BMW M2 Join Date: May 2018 Location: Putnam County, NY iTrader: (0)	M2 Brake Issue I tracked my M2 at Watkins Glen and the car was wonderful, however, I have a bad rumble when I step on the brake pedal now, and a groaning noise. Second time this has happened...I am told this could be from the rotors glazing? It did go away the first time, but this time seems much worse. Has anyone else experienced this? This is unacceptable for a car that is advertised as a track-ready car. Should not happen. Also, how do I cure the problem?
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05-05-2018, 12:55 AM	#2
Bee Pee Brigadier General 1774 Rep 4,510 Posts Drives: AW M2 DCT Join Date: Jun 2010 Location: SW London iTrader: (3)	Pad deposits after a track day - re-do brake pad bed in procedure should clean up the discs nicely. __________________ Fettled M135i EB AT then AW M2 DCT - both gone but not forgotten: Current '22 X3M LCI..
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05-06-2018, 09:27 AM	#3
nkwrite Registered 3 Rep 2 Posts Drives: 2017 BMW M2 Join Date: May 2018 Location: Putnam County, NY iTrader: (0)	Thanks! I'll give it a shot and report back.
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05-06-2018, 09:37 AM	#4
boostm3 Lieutenant Colonel 683 Rep 1,608 Posts Drives: '18 LBB M2 6MT Exec Join Date: Sep 2006 Location: Parkland, Fl iTrader: (0)	Are you on stock pads? __________________ Boostm3 '18 LBB MT M2 Exec pkg, Moonroof, Production 7/6/17
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05-06-2018, 01:47 PM	#5
pal Captain 433 Rep 753 Posts Drives: Z4 M Coupe Join Date: Nov 2007 Location: Seattle, WA iTrader: (2)	If you ran with stock pads and stability control, the material has likely broken down a bit (chunked) and cracked. This will normally give you the grinding noise later, likely exacerbated with drilled rotors. It’s not M2 or BMW specific. If you take the pads off, you will likely see physical evidence of this.
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05-06-2018, 04:01 PM	#8
M+M Second Lieutenant 227 Rep 245 Posts Drives: M2 DCT MPerformance coilovers Join Date: Apr 2016 Location: New Zealand iTrader: (0) Garage List 1998 Subaru Impreza ... [0.00] 2016 BMW M2 [0.00] 1995 Fraser Clubman ... [0.00]	very hard to get a pad that can cover road and track well. Especially if you are going hard at the track. All track pads will screech sooner or later on the road and become annoying in city driving. And then road pads aren't up to it for prolonged track use. You may be finding it worse this time because you are going faster with a bit more familiarity.
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05-07-2018, 01:43 AM	#14
eeyang92 Captain 319 Rep 660 Posts Drives: LBB M2 LCI 6MT Join Date: Oct 2017 Location: CA iTrader: (0)	I ran into the same issue with stock pads. I ended up purchasing rs29s to scrape off the old deposits + my next hdpe event. My new issue was that I ended up boiling the stock fluid with the new pads, so now I have Castrol srf.
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05-07-2018, 04:14 PM	#19
M+M Second Lieutenant 227 Rep 245 Posts Drives: M2 DCT MPerformance coilovers Join Date: Apr 2016 Location: New Zealand iTrader: (0) Garage List 1998 Subaru Impreza ... [0.00] 2016 BMW M2 [0.00] 1995 Fraser Clubman ... [0.00]	yep just switch to track fluid permanently. SRF expensive but much better for a dd car as it resists moisture better. there other threads talking about this.
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05-24-2018, 07:12 PM	#22
Smiley1175 Major 281 Rep 1,017 Posts Drives: M2 Join Date: Jun 2011 Location: Melbourne iTrader: (0)	I'm with the OP on this one. The standard pads BMW use are great for the road but shit anywhere else. I ran my Porsche on the track straight from the showroom and never had the issues I've had with BMW. If you're still getting the grinding sound or vibrations, get the discs machined and swap pads. Simple rule, don't ever bother with the BMW pads on the track, swap them before going out along with better fluid.
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