Brake Fluid 101

Larrio Andretti · 06-06-2018, 01:55 AM

The brake fluid you use is directly related to how your brakes will perform, but this fluid is often the most neglected maintenance item in a daily driven car. Neglect the maintenance of this fluid on the track and you will learn in a hurry how important it really is.

Brake fluid is simply hydraulic fluid…. An uncompressible fluid used to transmit force to the brake piston acting on the pad. Brake fluid is fragile. It’s hygroscopic which means it will absord water. If the brake fluid gets too hot it boils.The more water the brake fluid contains the lower the boiling point. If you boil the fluid you form bubbles of water vapor which are very compressible. The fluid no longer has the ability to transmit braking energy from the pedal to the caliper. The pedal goes soft and your ability to slow the car is compromised.

Air trapped in the line is also compressible and will cause a soft pedal all the time not just when hot.

In order to keep this from happening at the track you should at minimum bleed your brakes until the fluid runs clear. If your brake fluid is more than 6 months old it should be changed even if the car was never used. As it sits the fluid is absorbing water vapor from the air. How much? I don’t think anyone knows. But just to be safe it’s a good idea to use fresh fluid.

The type of fluid you use will ultimately be determined by your vehicle owners manual, but for the purpose of this article we will assume a modern car which operates on DOT type 3 fluid. DOT type 4 fluid is interchangeable with DOT 3. DOT 4 brake fluids have higher dry boiling points, but are unfortunately more hygroscopic than type 3 which is why it needs to be changed often. Don’t attempt a road course on DOT 3 fluid. It just won’t perform well.

Popular fluids for track days are ATE Super Blue which is relatively cheap at about $12 per liter. It’s dry boiling point is 536F, and it’s wet boiling point is 392F. MOTUL RBF600 is the next step up and is $20 per ½ liter. The dry boiling point is 593F, and the wet is 420. So even when it’s completely saturated it’s got a higher boiling point than the ATE Super Blue.

The ultimate in brake fluids are ester based. These include Castrol SRF, Endless RF650, AP Racing 600 and Brembo LFC600. Endless RF650, Brembo and Castrol are used exclusively in Formula 1 & Porsche GT3Cup cars. 1 liter of these brake fluids costs about $60-$80. Yeah… you read that right.

Boiling Points dry/wet in farenheit:
Brembo LCF 600: 600/399
Endless RF 650: 622/424
Castrol SRF: 590/518
Motul 660: 617/400

Wet boiling point on the Castrol SRF is impressive and significantly better than all others. You can see that Castrol didn't lose much performance between dry and wet. If you want the ultimate these are your choices but overkill for anyone reading this post.

I stick with the MOTUL RBF600 and bleed 1 liter through all 4 calipers before each track day. I have never had a problem with fade. The most epensive brake fluids come at a premium price and are in the realm of diminishing returns for money spent. They are better on paper but do you really need it.

Choose the most suitable fluid for your budget and brake deep and hard with confidence at you next track day!

Retro69 · 06-06-2018, 07:25 AM

Thank you for this great info!

Sent from my iPhone using Tapatalk

JB'sZL1 · 06-06-2018, 07:29 AM

Good info.

I will add synthetic brake fluid is available and it is not hygroscopic.

Badgerbimmer · 06-06-2018, 07:47 AM

Castrol SRF period

Larrio Andretti · 06-06-2018, 01:30 PM

Quote:

Originally Posted by JB'sZL1

Good info.

I will add synthetic brake fluid is available and it is not hygroscopic.

Are you referring to DOT 5? That has no application for our Camaro so I didn’t mention it. It’s silicone based and not compatible.

JB'sZL1 · 06-06-2018, 01:57 PM

Quote:

Originally Posted by Larrio Andretti

Are you referring to DOT 5? That has no application for our Camaro so I didn’t mention it. It’s silicone based and not compatible.

DOT3 synthetic is also available. I mention it because you mentioned hygroscopicity...and that brake fluid ought to be changed every six months. I'm not referencing it for track use, even though there is a high temp fluid.

ninetres · 06-06-2018, 02:04 PM

Hold up. You use 4L to bleed before each track day????? Or 1 divided up by all 4 corners? If 4.....that’s a fawkton or fluid and way more than anyone I know that races.

Akura · 06-06-2018, 02:36 PM

Always used in all my cars RBF600 and worked flawless, changed every year.

Crash76 · 06-06-2018, 03:25 PM

Motul 660 here

Ryephile · 06-06-2018, 04:29 PM

Quote:

Originally Posted by Larrio Andretti

...but for the purpose of this article ...

Since you didn't write it, how about sharing the source?

Larrio Andretti · 06-06-2018, 05:51 PM

I wrote it. I have a blog for my race car. Thought I’d post it here to be helpful. Credit is to me. You shouldnt make assumtions in an accusatory manner.

kropscamaro16 · 06-06-2018, 06:30 PM

i used motul 600 and used wilwood 550 in my old car lol good stuff way better than oem

Stephen12ZL1 · 06-06-2018, 08:37 PM

Motul 600 is excellent and has never let me down! I have 2000 miles at VIR in my ZL1!

06-06-2018, 01:55 AM	#1
Larrio Andretti Drives: Really Fast Join Date: Aug 2017 Location: In The Woods Posts: 238	Brake Fluid 101 The brake fluid you use is directly related to how your brakes will perform, but this fluid is often the most neglected maintenance item in a daily driven car. Neglect the maintenance of this fluid on the track and you will learn in a hurry how important it really is. Brake fluid is simply hydraulic fluid…. An uncompressible fluid used to transmit force to the brake piston acting on the pad. Brake fluid is fragile. It’s hygroscopic which means it will absord water. If the brake fluid gets too hot it boils.The more water the brake fluid contains the lower the boiling point. If you boil the fluid you form bubbles of water vapor which are very compressible. The fluid no longer has the ability to transmit braking energy from the pedal to the caliper. The pedal goes soft and your ability to slow the car is compromised. Air trapped in the line is also compressible and will cause a soft pedal all the time not just when hot. In order to keep this from happening at the track you should at minimum bleed your brakes until the fluid runs clear. If your brake fluid is more than 6 months old it should be changed even if the car was never used. As it sits the fluid is absorbing water vapor from the air. How much? I don’t think anyone knows. But just to be safe it’s a good idea to use fresh fluid. The type of fluid you use will ultimately be determined by your vehicle owners manual, but for the purpose of this article we will assume a modern car which operates on DOT type 3 fluid. DOT type 4 fluid is interchangeable with DOT 3. DOT 4 brake fluids have higher dry boiling points, but are unfortunately more hygroscopic than type 3 which is why it needs to be changed often. Don’t attempt a road course on DOT 3 fluid. It just won’t perform well. Popular fluids for track days are ATE Super Blue which is relatively cheap at about $12 per liter. It’s dry boiling point is 536F, and it’s wet boiling point is 392F. MOTUL RBF600 is the next step up and is $20 per ½ liter. The dry boiling point is 593F, and the wet is 420. So even when it’s completely saturated it’s got a higher boiling point than the ATE Super Blue. The ultimate in brake fluids are ester based. These include Castrol SRF, Endless RF650, AP Racing 600 and Brembo LFC600. Endless RF650, Brembo and Castrol are used exclusively in Formula 1 & Porsche GT3Cup cars. 1 liter of these brake fluids costs about $60-$80. Yeah… you read that right. Boiling Points dry/wet in farenheit: Brembo LCF 600: 600/399 Endless RF 650: 622/424 Castrol SRF: 590/518 Motul 660: 617/400 Wet boiling point on the Castrol SRF is impressive and significantly better than all others. You can see that Castrol didn't lose much performance between dry and wet. If you want the ultimate these are your choices but overkill for anyone reading this post. I stick with the MOTUL RBF600 and bleed 1 liter through all 4 calipers before each track day. I have never had a problem with fade. The most epensive brake fluids come at a premium price and are in the realm of diminishing returns for money spent. They are better on paper but do you really need it. Choose the most suitable fluid for your budget and brake deep and hard with confidence at you next track day! __________________ THIS SPACE FOR RENT

06-06-2018, 07:25 AM	#2
Retro69 Drives: 2018 Camaro ZL1 Join Date: Jun 2011 Location: Morgan, UT Posts: 1,359	Thank you for this great info! Sent from my iPhone using Tapatalk __________________

06-06-2018, 07:47 AM	#4
Badgerbimmer Drives: ZL1 A10 Join Date: Dec 2017 Location: Wisconsin Posts: 306	Castrol SRF period __________________ My rides: 2017 Camaro ZL1 A10 2015 Jeep Grand Cherokee Diesel 2012 Audi S4 1992 Porsche America Roadster 1990 BMW 325Ic

06-06-2018, 02:36 PM	#8
Akura Drives: ´18 ZL1 A10 Red Hot 😍 Join Date: Jan 2016 Location: Madrid, SPAIN Posts: 347	Always used in all my cars RBF600 and worked flawless, changed every year. __________________ First ZL1 in Spain (Madrid)! Red Hot, A10, PDR, carbon fiber hood & grounds effects...

06-06-2018, 05:51 PM	#11
Larrio Andretti Drives: Really Fast Join Date: Aug 2017 Location: In The Woods Posts: 238	I wrote it. I have a blog for my race car. Thought I’d post it here to be helpful. Credit is to me. You shouldnt make assumtions in an accusatory manner. __________________ THIS SPACE FOR RENT

06-06-2018, 07:29 AM	#3
JB'sZL1 Drives: 2013 ZL1 and 2019 Ram Laramie Join Date: May 2017 Location: Milwaukee Posts: 1,259	Good info. I will add synthetic brake fluid is available and it is not hygroscopic.

06-06-2018, 02:04 PM	#7
ninetres Drives: Crush ZLE M6 \| 2000 Corvette FRC Join Date: Jun 2010 Location: Cencal Posts: 1,659	Hold up. You use 4L to bleed before each track day????? Or 1 divided up by all 4 corners? If 4.....that’s a fawkton or fluid and way more than anyone I know that races.

06-06-2018, 03:25 PM	#9
Crash76 Team 913 Drives: '14 ZL1, '15 Jeep GC, ‘22 Ram 2500 Join Date: Apr 2015 Location: USA, Central CA Posts: 1,119	Motul 660 here

06-06-2018, 06:30 PM	#12
kropscamaro16 Drives: 2016 1ss camaro Join Date: Feb 2016 Location: 909 Posts: 9,813	i used motul 600 and used wilwood 550 in my old car lol good stuff way better than oem __________________ 16 1SS NIGHTFALL GRAY METALLIC WITH NPP #BECAUSERACECAR #SAVETHEMANUALS

06-06-2018, 08:37 PM	#13
Stephen12ZL1 Drives: '21 ZLE A10 Join Date: May 2012 Location: Mechanicsville, VA Posts: 6,808	Motul 600 is excellent and has never let me down! I have 2000 miles at VIR in my ZL1! __________________ '21 ZLE A10 Wild Cherry PDR 2:00.78 VIR Full 10.68@131.69 1.68 60' '17 ZL1 A10 Mosaic Black PDR/Nav 2:03.08 VIR Full 11.003@129.2 1.75 (sold) '15 Z/28 #325 Black a/c & stereo. 2:10.1 VIR Full (sold) '12 ZL1 A6 Black 10.52@131 1.55 60' 2:13 VIR Full (sold)

User Name		Remember Me?
Password