Brake fluid and pads for track day

cw128 · 01-06-2015, 09:49 PM

So I took my M235i for a few laps around a local track not long ago, and although it was great fun the one thing that really let it down were the brakes. After about 2 laps the brake pedal got very soft and spongy.

Forgive my lack of mechanical knowledge, but my first thought was that it just needs some better pads but a few other people have told me that this is often caused by the brake fluid overheating too quickly. I'm thinking of doing a full day at the track in it very soon, so I'd like to get this sorted out before then if possible.

So a couple of questions:

1. Which would you suggest doing out of the two (brake fluid change or pad change) if I can only do one before I do the next track day?
2. Which brake fluid would people recommend for track (and street) use?
3. Would it still be worth getting better pads and if so, any particular pads you'd recommend for this car for track and street?

Oh and just for fun here's a pic of it on track

MrBucket · 01-07-2015, 03:48 AM

Pedal going soft would be the fluid boiling probably. Honestly I'd do both if possible, but the fluid might make the bigger difference if it went soft that fast just for now.

LDSM · 01-07-2015, 04:48 AM

Just wanted to say that's a great pic

bluemeanie · 01-07-2015, 04:57 AM

Motul 600 is widely used as a high quality high boiling point brake fluid. It's what I use in my track car.

ketema · 01-07-2015, 09:35 AM

I had the same problem on my first track day with the car as well. I changed the fluid to Torque RT 700, changed to steel braided lines, got new rotors from Stop Tech and pads from Pagid. RSLs. Did I need all of it? Probably not, but the combination made and incredible difference. The bite of the Pagids is just immense. No fade and my second track day was on a course that demanded more of the brakes. I am happy with the upgrades, only negative part is that the pagid pads are noisy. But to me the stopping power is worth the trade off

cw128 · 01-07-2015, 10:10 AM

Thanks for all the replies guys - I've got it booked in to get the standard fluid replaced with some race spec fluid now. I guess I'll do this track day next week and if it still doesn't feel great I'll go for the braided lines and better pads.

foamie · 01-07-2015, 10:14 AM

Dedicated track pads and high performance brake fluid as suggested by others.
My street pads never survive a whole day on the track but the dedicated pads are good for a couple or more events; when the brakes go soft, I do a cool-down lap then bleed the brakes (i use speed bleeders) and go out again. Check brakes and car after every session to spot potential problems and stay safe.

Nice pic

overcoil · 01-07-2015, 10:30 AM

As an aside, worth reading about air in brake lines and brake fluid boil at the calipers.
Also google racing braking technique and learn the problem with "limo" style braking and conversely the benefits of using the initial application of braking to get the weight of the car into the front tires.
Also, how the time off the brakes is time for brake cooling and notice other cars on the track how they perform and if they are using aftermarket cooling ducts.

NEUE02 · 01-07-2015, 05:38 PM

I use Pagid RS 29 racing brake pads. Great bite and fade free. They last a very long time and are gentle on rotors. Also, the brake dust is not corrosive to the wheels or painted surfaces. For fluid I like ATE Gold. It has a slightly lower boiling temp than Motul 600 but it is less hygroscopic so you can leave it in all year long with less degradation than Motul.

Here's a pic from my latest outing.

Liquidpaper · 01-08-2015, 03:28 PM

Before I ever went out on the track, I put in ATE Gold as well. Seemed to help a lot -- didn't notice a whole lot of brake fade. Then again, I am a very novice driver and probably don't push the brakes nearly as hard as some of these guys do.

That being said, the stock pads aren't THAT bad. They hold up okay. Also, options are limited at this point for aftermarket pads for the M235i -- your only real choice is race dedicated, or stock at the moment. I'd probably spring for some EBC Yellowstuff when it becomes available.

Braided brake lines are good too, but again, see what you need. You might be fine with the stock lines and some high temp brake fluid.

Also, great picture.

spyerx · 01-11-2015, 11:07 AM

I've yet to stick my head under the wheel well of my wife's new m235i, but I suspect that cooling is not the best + the pads are a compromise for street use. ALWAYS change fluid to a high boil fluid before track use. I wouldn't bother with braided lines. Fluid, cooling, pads, and rotors.

I use endless in my gt3rs. The ONLY brake fluids I would ever use on track is endless, castor srf, or motul 660.

hoppy6698 · 01-11-2015, 03:22 PM

Quote:

Originally Posted by bluemeanie

Motul 600 is widely used as a high quality high boiling point brake fluid. It's what I use in my track car.

Is this the same stuff? Motul RBF600 Synthetic DOT 4 Brake Fluid ($19 / pint)

Supernaut · 01-11-2015, 03:32 PM

Out of curiosity,
1-how much fluid did it take to fill and flush out the system?
2-how accessible is the clutch bleeder?
3-anyone find SpeedBleeders for this car?

th1rd3y3 · 01-11-2015, 04:25 PM

If your pads aren't fading but you're losing pedal pressure, fluid would be the best for you. Dedicated track pads certainly can't hurt, but it sounds like at this point you're not running out of pad. Both would certainly help though. Better pads, will allow less time on the brakes so in theory would help with temps as well, but given that the factory fluid is most likely not performance oriented. If you had to choose do the fluid.

If you're doing it yourself, pick up one of these: http://motiveproducts.3dcartstores.c...der_p_115.html

Makes bleeding a painless one man operation. I've had one for years and love it. Keep in mind also to change out your fluid after events and also high temp stuff is supposed to only be used for a year before swapping even if it doesn't boil on you.

cw128 · 01-12-2015, 10:54 AM

Yeah it does seem like its the fluid rather than the pads from what everyone has said. I'm getting the fluid replaced with Castrol SRF tomorrow and got a track day on Friday so will report back on whether or not it is any better

Oyinko · 02-03-2015, 04:00 PM

I would like to add stainless brake lines + a new brake fluid for my track day. Can I ask my dealership to take care of it? And if yes, how much will it cost?

Liquidpaper · 02-03-2015, 04:23 PM

Quote:

Originally Posted by Oyinko

I would like to add stainless brake lines + a new brake fluid for my track day. Can I ask my dealership to take care of it? And if yes, how much will it cost?

Dealers will not do non-OEM services. You're going to have to find an independent BMW mechanic.

overcoil · 02-03-2015, 04:25 PM

Quote:

Originally Posted by Oyinko

I would like to add stainless brake lines + a new brake fluid for my track day. Can I ask my dealership to take care of it? And if yes, how much will it cost?

SS braided flex hoses - dealer probably won't do it since it reduces the ability to inspect for damage.

m235i_GM · 04-13-2016, 03:11 PM

I had the same issue. They became spongy and pedal travel was longer, braking distance decreased. I took mine to the dealer and he said the pads have plenty of life left in them for upto 22,000 miles. And they would not do a fluid flush as the next bmw regular service for a brake fluid flush is only in May 2017. Forget asking them for ATE specific fluids. I am going to go to a bmw specialist service guy and get a flush done.

How did your next track day go?

HP Autosport · 04-13-2016, 09:01 PM

1. Which would you suggest doing out of the two (brake fluid change or pad change) if I can only do one before I do the next track day?

Pad change. You will likely exceed the operating temperature of the pads first, then the fluid.

2. Which brake fluid would people recommend for track (and street) use?

If you don't want to flush it out after/before each track day, Castrol SRF. With this fluid all you need to do is bleed the air out right before each event and you are good to go. Flush it all out after each season and you are ready for the next.

3. Would it still be worth getting better pads and if so, any particular pads you'd recommend for this car for track and street?

Right now, the most popular is the RS29. The F8x take the same pad and lots of guys swear by it. Porsche owners too. Full information on the RS29 here:

http://www.hpashop.com/searchquick-s...?keywords=rs29

As for a street pad, the stock pads are fine. Stoptech makes a good sport pad with less dust and slightly higher maximum operating temperature.

i8ur911 · 04-15-2016, 08:19 PM

Quote:

Originally Posted by HP Autosport

1. Which would you suggest doing out of the two (brake fluid change or pad change) if I can only do one before I do the next track day?

Pad change. You will likely exceed the operating temperature of the pads first, then the fluid.

2. Which brake fluid would people recommend for track (and street) use?

If you don't want to flush it out after/before each track day, Castrol SRF. With this fluid all you need to do is bleed the air out right before each event and you are good to go. Flush it all out after each season and you are ready for the next.

3. Would it still be worth getting better pads and if so, any particular pads you'd recommend for this car for track and street?

Right now, the most popular is the RS29. The F8x take the same pad and lots of guys swear by it. Porsche owners too. Full information on the RS29 here:

http://www.hpashop.com/searchquick-s...?keywords=rs29

As for a street pad, the stock pads are fine. Stoptech makes a good sport pad with less dust and slightly higher maximum operating temperature.

I would actually, respectfully, disagree on this.

Most cars on track will suffer from boiling brake fluid before glazing pads. In fact, I use the stock M Performance pads on my car with RBF600 and the car has been great (7 days at Palmer Motorsport Park.....on stock pads....running in group 2 with BMWCCA). So, in my opinion, I would swap fluid first.

Regarding what fluid, I'd recommend ATE200 (Gold) or Motul RBF600. The Motul fluid will be more hydroscopic, but had a higher boiling point.....should be changed every 6 months or so.

There shouldn't be any air in the system once bled either.

I do agree that the Pagid RS29 pad is likely the most popular. It's expensive, but you get what you pay for too.

cw128 · 05-23-2016, 07:22 AM

FWIW, it did turn out to be the brake fluid. Once that had been replaced with Castrol SRF, the pedal didn't go soft after a few laps like it did before.

I also eventually replaced the front brake pads with EBC Red Stuff and they felt a lot better than the stock pads just for normal road driving (much better initial bite). Swapped the car for an M4 recently though so I'm afraid I can't say how good those pads would have been on track as I didn't do any more track days in it after changing the pads.

01-06-2015, 09:49 PM	#1
cw128 Private First Class 67 Rep 112 Posts Drives: 2015 M4 Join Date: Oct 2013 Location: United Kingdom iTrader: (0)	Brake fluid and pads for track day So I took my M235i for a few laps around a local track not long ago, and although it was great fun the one thing that really let it down were the brakes. After about 2 laps the brake pedal got very soft and spongy. Forgive my lack of mechanical knowledge, but my first thought was that it just needs some better pads but a few other people have told me that this is often caused by the brake fluid overheating too quickly. I'm thinking of doing a full day at the track in it very soon, so I'd like to get this sorted out before then if possible. So a couple of questions: 1. Which would you suggest doing out of the two (brake fluid change or pad change) if I can only do one before I do the next track day? 2. Which brake fluid would people recommend for track (and street) use? 3. Would it still be worth getting better pads and if so, any particular pads you'd recommend for this car for track and street? Oh and just for fun here's a pic of it on track Attached Images
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01-07-2015, 03:48 AM	#2
MrBucket Captain 257 Rep 721 Posts Drives: '17 AW M2 6MT Exec Pack Join Date: Aug 2014 Location: United States iTrader: (0)	Pedal going soft would be the fluid boiling probably. Honestly I'd do both if possible, but the fluid might make the bigger difference if it went soft that fast just for now.
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01-07-2015, 04:48 AM	#3
LDSM Captain 344 Rep 686 Posts Drives: ... Join Date: Jun 2012 Location: ... iTrader: (0)	Just wanted to say that's a great pic
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01-07-2015, 04:57 AM	#4
bluemeanie Private 17 Rep 76 Posts Drives: 228i=awesome Join Date: Nov 2014 Location: NoVa iTrader: (0)	Motul 600 is widely used as a high quality high boiling point brake fluid. It's what I use in my track car.
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01-07-2015, 09:35 AM	#5
ketema Second Lieutenant 73 Rep 201 Posts Drives: 2015 M235i Join Date: Aug 2014 Location: Oviedo, FL iTrader: (0)	I had the same problem on my first track day with the car as well. I changed the fluid to Torque RT 700, changed to steel braided lines, got new rotors from Stop Tech and pads from Pagid. RSLs. Did I need all of it? Probably not, but the combination made and incredible difference. The bite of the Pagids is just immense. No fade and my second track day was on a course that demanded more of the brakes. I am happy with the upgrades, only negative part is that the pagid pads are noisy. But to me the stopping power is worth the trade off Attached Images __________________ 2015 6M Black Sapphire Metallic \| MPE w/Carbon Tips \| Digital MP Steering Wheel \| Carbon Interior \| StopTech Slotted Rotors \| Pagid RSL1 Race Pads \| KW Clubsport Coilovers \| DINAN Stage 2 and Carbon air intake \| Clutch Masters Lightweight Performance Clutch and Flywheel \| Hotchkis Anti-Roll Bars \| Enkei RS05RR 18" Racing Wheels
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01-07-2015, 10:10 AM	#6
cw128 Private First Class 67 Rep 112 Posts Drives: 2015 M4 Join Date: Oct 2013 Location: United Kingdom iTrader: (0)	Thanks for all the replies guys - I've got it booked in to get the standard fluid replaced with some race spec fluid now. I guess I'll do this track day next week and if it still doesn't feel great I'll go for the braided lines and better pads.
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01-07-2015, 10:14 AM	#7
foamie Enlisted Member 10 Rep 36 Posts Drives: M235i Join Date: Dec 2014 Location: MN iTrader: (0)	Dedicated track pads and high performance brake fluid as suggested by others. My street pads never survive a whole day on the track but the dedicated pads are good for a couple or more events; when the brakes go soft, I do a cool-down lap then bleed the brakes (i use speed bleeders) and go out again. Check brakes and car after every session to spot potential problems and stay safe. Nice pic
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01-07-2015, 10:30 AM	#8
overcoil Major General 3074 Rep 5,577 Posts Drives: M235i 6spd Join Date: Dec 2013 Location: Mid-Atlantic iTrader: (0)	As an aside, worth reading about air in brake lines and brake fluid boil at the calipers. Also google racing braking technique and learn the problem with "limo" style braking and conversely the benefits of using the initial application of braking to get the weight of the car into the front tires. Also, how the time off the brakes is time for brake cooling and notice other cars on the track how they perform and if they are using aftermarket cooling ducts.
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01-07-2015, 05:38 PM	#9
NEUE02 Lieutenant 267 Rep 554 Posts Drives: M235i Join Date: Dec 2014 Location: St Louis iTrader: (0)	I use Pagid RS 29 racing brake pads. Great bite and fade free. They last a very long time and are gentle on rotors. Also, the brake dust is not corrosive to the wheels or painted surfaces. For fluid I like ATE Gold. It has a slightly lower boiling temp than Motul 600 but it is less hygroscopic so you can leave it in all year long with less degradation than Motul. Here's a pic from my latest outing. __________________ The Stable 2015 BMW M235i \| 2014 Porsche Carrera S \| 2017 Porsche Macan GTS \| 1996 Porsche Carrera 4S
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01-08-2015, 03:28 PM	#10
Liquidpaper Captain 450 Rep 845 Posts Drives: '15 M235i Join Date: Jun 2014 Location: SoCal iTrader: (0) Garage List 2015 BMW M235i [0.00]	Before I ever went out on the track, I put in ATE Gold as well. Seemed to help a lot -- didn't notice a whole lot of brake fade. Then again, I am a very novice driver and probably don't push the brakes nearly as hard as some of these guys do. That being said, the stock pads aren't THAT bad. They hold up okay. Also, options are limited at this point for aftermarket pads for the M235i -- your only real choice is race dedicated, or stock at the moment. I'd probably spring for some EBC Yellowstuff when it becomes available. Braided brake lines are good too, but again, see what you need. You might be fine with the stock lines and some high temp brake fluid. Also, great picture.
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01-11-2015, 11:07 AM	#11
spyerx New Member 0 Rep 9 Posts Drives: m235i Join Date: Jan 2015 Location: us iTrader: (0)	I've yet to stick my head under the wheel well of my wife's new m235i, but I suspect that cooling is not the best + the pads are a compromise for street use. ALWAYS change fluid to a high boil fluid before track use. I wouldn't bother with braided lines. Fluid, cooling, pads, and rotors. I use endless in my gt3rs. The ONLY brake fluids I would ever use on track is endless, castor srf, or motul 660.
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01-11-2015, 03:32 PM	#13
Supernaut Little Deuce Coupe 391 Rep 635 Posts Drives: SO M2C Join Date: Sep 2014 Location: Virginia Beach iTrader: (0) Garage List 2020 BMW M2 competi ... [0.00]	Out of curiosity, 1-how much fluid did it take to fill and flush out the system? 2-how accessible is the clutch bleeder? 3-anyone find SpeedBleeders for this car? __________________ ex: 2004 Thermonuclear Yellow RX-8\|6MT ex: 2015 Estoril Blue M235i \|6MT\|slicktop\|MP exhaust - PCD 2020 Sunset Orange M2C\|6MT\|Black 788s
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01-11-2015, 04:25 PM	#14
th1rd3y3 Private First Class 31 Rep 199 Posts Drives: '20 M340i xDrive Join Date: May 2013 Location: United States iTrader: (0)	If your pads aren't fading but you're losing pedal pressure, fluid would be the best for you. Dedicated track pads certainly can't hurt, but it sounds like at this point you're not running out of pad. Both would certainly help though. Better pads, will allow less time on the brakes so in theory would help with temps as well, but given that the factory fluid is most likely not performance oriented. If you had to choose do the fluid. If you're doing it yourself, pick up one of these: http://motiveproducts.3dcartstores.c...der_p_115.html Makes bleeding a painless one man operation. I've had one for years and love it. Keep in mind also to change out your fluid after events and also high temp stuff is supposed to only be used for a year before swapping even if it doesn't boil on you.
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01-12-2015, 10:54 AM	#15
cw128 Private First Class 67 Rep 112 Posts Drives: 2015 M4 Join Date: Oct 2013 Location: United Kingdom iTrader: (0)	Yeah it does seem like its the fluid rather than the pads from what everyone has said. I'm getting the fluid replaced with Castrol SRF tomorrow and got a track day on Friday so will report back on whether or not it is any better
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02-03-2015, 04:00 PM	#16
Oyinko Private First Class 40 Rep 176 Posts Drives: M235i Join Date: Apr 2014 Location: SF Bay Area iTrader: (0)	I would like to add stainless brake lines + a new brake fluid for my track day. Can I ask my dealership to take care of it? And if yes, how much will it cost?
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04-13-2016, 03:11 PM	#19
m235i_GM Enlisted Member 5 Rep 36 Posts Drives: 14 M235i Join Date: Jul 2015 Location: Michigan iTrader: (0)	I had the same issue. They became spongy and pedal travel was longer, braking distance decreased. I took mine to the dealer and he said the pads have plenty of life left in them for upto 22,000 miles. And they would not do a fluid flush as the next bmw regular service for a brake fluid flush is only in May 2017. Forget asking them for ATE specific fluids. I am going to go to a bmw specialist service guy and get a flush done. How did your next track day go?
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04-13-2016, 09:01 PM	#20
HP Autosport Supreme Allied Commander 3815 Rep 54,307 Posts Drives: F80 M3 Join Date: Mar 2007 Location: Santa Barbara, AP, Brembo, GIAC, Koni, Ohlins, Performance Friction, www.hpautosport.com iTrader: (36)	1. Which would you suggest doing out of the two (brake fluid change or pad change) if I can only do one before I do the next track day? Pad change. You will likely exceed the operating temperature of the pads first, then the fluid. 2. Which brake fluid would people recommend for track (and street) use? If you don't want to flush it out after/before each track day, Castrol SRF. With this fluid all you need to do is bleed the air out right before each event and you are good to go. Flush it all out after each season and you are ready for the next. 3. Would it still be worth getting better pads and if so, any particular pads you'd recommend for this car for track and street? Right now, the most popular is the RS29. The F8x take the same pad and lots of guys swear by it. Porsche owners too. Full information on the RS29 here: http://www.hpashop.com/searchquick-s...?keywords=rs29 As for a street pad, the stock pads are fine. Stoptech makes a good sport pad with less dust and slightly higher maximum operating temperature.
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05-23-2016, 07:22 AM	#22
cw128 Private First Class 67 Rep 112 Posts Drives: 2015 M4 Join Date: Oct 2013 Location: United Kingdom iTrader: (0)	FWIW, it did turn out to be the brake fluid. Once that had been replaced with Castrol SRF, the pedal didn't go soft after a few laps like it did before. I also eventually replaced the front brake pads with EBC Red Stuff and they felt a lot better than the stock pads just for normal road driving (much better initial bite). Swapped the car for an M4 recently though so I'm afraid I can't say how good those pads would have been on track as I didn't do any more track days in it after changing the pads.
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