[gokusan]

Hello to everybody. Im new on this side and this is my first post.

So i had and i have a problem with brakes. Becouse of that i crashed two cars. M6 F13 and M2 F87 comp.

Both time went brake pedal to the flor. And even after pumping padel nothing heppend.

So in march i crashed M6. It was 10 days after winter i had summer tyres on. I was driving lets say a little bit of dynamic but nothing sirius becuse there were pars of tarmac dry and parts of tarmac wet. road was up hill. Then i was driving normal down hill. When i went down i have decidet that i turn to one good road. I was pushing hard. Down and back up. Up hill disks were glowing orange... Again i was driving normal and after 3km of normal driving brake pedal went to the flor. I tryed 20 times and it did slow down car from 100km/h to 70km/h. But this corner was ok. Next was herpin. And even if i tryed again 20 times nothing didnt heppend and i crashed with 60km/h in to the wall.

Brake pads were OEM brake fluid was 2 month old motul 660.

Next is M2 comp. one week ago i was on a race track. I made 8 stints for 20min. I have destroyed 1 pair of ferodo ds 1.11 in front, 1/2 ferodo ds 3.12 in front and 1 pair od ds2500 in the back. One day before TD i have changed brake fluid and i put castol SRF. Rotors are stock car is stock.

So i am driving realy fast all day, brake calipers were olive green from previus TD but in this TD they become black. And rear were green. Everything is ok good day, last stint or lets say last 5min of TD. Brakes are ok also all lap before crash even last two corners befor crash.

So i am doing 225km/h on start/finish line it is long around 700m when i hit brake pedal as hard as i can. Like 60 laps before. And nothing happens. Nothing. I relise i press againg and nothing. In this time i was 100m to late to do anything i pul hand brake and i go off the track with 210km/h. Go over the gravel over the grass direct in tyres with 120km/h by gps. in this time i made 630 spin and hit with left side. car totaled. i was "ok".

we took car to box left it ther to next day. next day i tryed brake pedal with engine off and on and both times brake pedal went down to the flor. nothing.

So where is the problem. OK i know its me i am wery agresive on braking but no brakes?

Is it possible that there is air inside? did brake fluid boil? master cilinder foult? is problem in calipers?

[HP Autosport]

Soft pedal is usually associated with air in the system. Try flushing/bleed the system and see what happens.

What happens if you pump the pedal several times?

[MooMooM2]

don't have much to add but 2nd time this week I hear of brakes failing on a track going pretty fast, other was a corvette and video on instagram, guy said he pressed brakes and went through the floor. Just glad you are ok!

[medphysdave]

It sounds like your brakes are getting really hot. Is it possible the the piston seals are melting and you're getting a loss of fluid? The day yo went back and checked the wrecked car was there fluid in the reservoir? I'm sure it's possible to boil even the best track focused fluid.

[gokusan]

So, brake pedal was next day the same. No power and pedal went to the flor. Dust seals were gone, also ruber on front lower arm was gone. So too much heat. It looks like brake oil boil.

Why is another question. I konw that i am agresive driver on track, that ds3.12 are to agresive brake pads, becouse they turn brake caliper to black, then alu pistons in calipers transfer too much heat inside caliper and brake cooling ist ok that i had. becouse i mount air duct, tube and change heat protection for piece that tube goes on. And problem is becouse that cranel or air cool just brake disk on inner side. And can disturbe air witch goes originali from center of the disk to out side of the disk. Now i need to fix also this and put inox/steinless steal brake pistons in caliper

[Sequence_]

Originally Posted by gokusan

So, brake pedal was next day the same. No power and pedal went to the flor. Dust seals were gone, also ruber on front lower arm was gone. So too much heat. It looks like brake oil boil.

Why is another question. I konw that i am agresive driver on track, that ds3.12 are to agresive brake pads, becouse they turn brake caliper to black, then alu pistons in calipers transfer too much heat inside caliper and brake cooling ist ok that i had. becouse i mount air duct, tube and change heat protection for piece that tube goes on. And problem is becouse that cranel or air cool just brake disk on inner side. And can disturbe air witch goes originali from center of the disk to out side of the disk. Now i need to fix also this and put inox/steinless steal brake pistons in caliper

How are you managing to do this??? does your m2 weigh 5 tonnes?

[chris719]

You have the blue brakes I assume. Crazy, but it sounds like you need an AP Racing or Alcon kit.

[rhyary]

Get Carbon Ceramic Brakes :-)

[gokusan]

yes i have blue calipers but rear are now olive green and front are black. You can do this with extremely hard driving combined with very agresive brake pads. Otherwise car is stock. weight is around 1580kg.

CC brakes are not ok becouse they produce same temperatures (i think) biggest problem is that it is better that you dont get any stone betwen dick and brake pade if you some how go out of the track. Stone will cut disc like its from paper. A lot of my friends went from CC to steal brakes.

Biggest advantege of CC in unspringed weight.

[gokusan]

Originally Posted by Sequence_

How are you managing to do this??? does your m2 weigh 5 tonnes?

https://www.youtube.com/@MatejRatko/videos

this are my videos. f30 335i RWD MT and blue M2OG are mine and i am driving.

M2comp that we are talking is my frends car but i was driving when we crashed. He was beside me inside car so he knows all the story and we dont have any problems. Car is on repair right now.

[gokusan]

Originally Posted by chris719

You have the blue brakes I assume. Crazy, but it sounds like you need an AP Racing or Alcon kit.

I was thinking to buying used silver, gold or red 6 piston OE brake calipers for my car. Silver red gold are all the same. Down side is aditional weight and that you cant change brake pads from back in 10min on a track...

[chris719]

Originally Posted by gokusan

I was thinking to buying used silver, gold or red 6 piston OE brake calipers for my car. Silver red gold are all the same. Down side is aditional weight and that you cant change brake pads from back in 10min on a track...

You should just get a proper setup like AP Racing or Alcon. The big BMW 6 piston calipers seem to be problematic for some people on track with pad knock-back. You’re good enough to turn the blue calipers black so I feel like you should get a real track-worthy setup. The M2 CSR uses Alcon front calipers.

[rhyary]

Originally Posted by gokusan

yes i have blue calipers but rear are now olive green and front are black. You can do this with extremely hard driving combined with very agresive brake pads. Otherwise car is stock. weight is around 1580kg.

CC brakes are not ok becouse they produce same temperatures (i think) biggest problem is that it is better that you dont get any stone betwen dick and brake pade if you some how go out of the track. Stone will cut disc like its from paper. A lot of my friends went from CC to steal brakes.

Biggest advantege of CC in unspringed weight.

.
There is a lot to like about carbon ceramic brakes. The new type from BMW have friction layer made of silicon carbide which does not oxedize at high temperature. CCBs can tolerate much higher temperatue than grey iron. If CCBs are damaged from stones, they can be refurbished. CCBs are better than iron on track, but they are expensive. So the issue is not “better”, they issue is cost/benefit. And cost is relative to what else you want to do with the money.

Check out rebrakeusa if your friends need refubishment.

[gokusan]

Well yes of course money playes big part in this upgrade. Becouse complete kit it is around 13k€ with TAX witch is more than 1/4 of price of the car.

[medphysdave]

A member just posted a great price for an Alcon front setup.

https://f87.bimmerpost.com/forums/sh....php?t=2042713

[Ratcher]

Sorry to say but I think you are the issue. Both your setups shouldn't be failing. And if so, not out of nowhere, you'd feel fading since there's no fading compensation on M cars.

[gokusan]

All lap before and last lap brakes were working normal. Even last two corners were ok where are speeds from 160 to 80 and last corner before start finish line from 150 to 100. And then its like mybee 700m of streight.

[jritt@essex]

A soft pedal indicates one of two things typically:

1. You have a leak somewhere in your system. The hydraulic brake system is a closed loop of non-compressible fluid. If you don't find any fluid escaping anywhere at any of the connections, and your brake fluid level isn't getting lower, then you don't have a leak.

2. You've boiled your brake fluid. This is the more common cause of a soft brake pedal that we see. If you get too much heat in the system, air bubbles form in the brake fluid that can compress. If you are boiling Castrol SRF and Motul 660, that means you are simply pouring more heat into the system than the current components can handle/get rid of. The underlying cause for boiled fluid is that your discs and pads are running too hot. Think of your brake system as a chain. If you discs are hot, that causes your pads to heat, which causes your caliper pistons to heat, which causes your caliper body and fluid to overheat.

The solution is getting your brake disc and pad temperatures down. That can usually be accomplished by a couple different ways. 1) Go to a larger disc that has more thermal mass and/or 2) Increase the thermal efficiency of the brake components. Since the OEM discs on the M2 Comp are already massive, you can't really go any bigger unless you plan to run 22" wheels!

All of the symptoms you describe below can be solved with one of our AP Racing by Essex Radi-CAL Competition Brake Kits. https://www.essexparts.com/my-vehicl...tion/F87%20All

So, brake pedal was next day the same. No power and pedal went to the flor. Dust seals were gone, also ruber on front lower arm was gone. So too much heat. It looks like brake oil boil.

Why is another question. I konw that i am agresive driver on track, that ds3.12 are to agresive brake pads, becouse they turn brake caliper to black, then alu pistons in calipers transfer too much heat inside caliper and brake cooling ist ok that i had. becouse i mount air duct, tube and change heat protection for piece that tube goes on. And problem is becouse that cranel or air cool just brake disk on inner side. And can disturbe air witch goes originali from center of the disk to out side of the disk. Now i need to fix also this and put inox/steinless steal brake pistons in caliper

Some comments on your points above:

The DS3.12 is not too aggressive when paired with the correct disc and caliper. We have thousands of happy customers using DS3.12, and these pads are winning endurance races at the elite level of motorsport.

Yes, aluminum pistons transfer heat very rapidly to the brake fluid. Our AP COmpetition Kits feature ventilated stainless still pistons to slow the transfer of heat to the fluid.

Your brake ducts may be hurting you more than helping you. We've found that in many cases self-installed brake ducts cause the brakes on road cars to run hotter than they do without ducts. If you have ducts installed, you may be trapping heat and reflecting more heat back onto the discs and pads. Please see our article here on that topic: https://www.essexparts.com/news-blog...n-my-track-car

Despite being smaller than the OEM discs, our AP Racing 372x34mm J Hook Discs flow more air and run considerably cooler than the stock discs. That brings disc, pad, piston, and fluid temperatures down considerably.

Our calipers also have anti-knockback springs as standard, and typically eliminate pad knockback and soft pedal.

Carbon ceramic discs are NOT the answer. They tend to do far worse on a track than one of our iron systems that are specifically designed for heavy track use and racing. Here's an article on that topic: https://www.essexparts.com/news-blog...tter-than-iron

[rhyary]

The article on CCB by Essexparts is
misleading. it talks about CCM, but BMW uses CCBH. It is true that CCM does not last long on the track. But there is away to bind a silicon Carbide friction layer to a CCM disk to make it durable.

CCBH uses a friction layer made out of silicon carbide and does not oxidize (burns) like CCM. BMW, Porsche, Audi and AMG all use silicon carbide friction layer. The durability of CCBH on track is a proven by many GT3 and GT3 RS cars. And there is no brake fade with all types of ccb disks, regardless how long they last or how much they cost. They don’t fade.

Attached is a picture of CCBH type disk:

If interested to learn about carbon ceramic brakes, join my group on Facebook:

https://m.facebook.com/groups/296265...ibextid=S66gvF

[medphysdave]

The silicon carbide layer creates a very hard surface with minimal wear. However, the carbon within the carbon matrix of the rotor oxidise at temperature beginning at 600C. The SC surface does not prevent the oxidation of the carbon. This is why Porsche, BMW, etc rotors are measured by weight and not rotor thickness.

If you can keep these rotors cool and run a pad that doesn't aggressively wear the SC layer, then they will truly last a lifetime.

Track use tends to push these rotors into the oxidation window.