Thread: Hi-Temp Brake Fluid

DOT 4 was invented for those who drive their Auto with the left foot resting on the brake.

Some manufacturers sell a grade called DOT 5.1
It's not a true DOT classification as it's not recognised by the Department of Transportation. Instead it's a version of DOT 4 which has a boiling point higher than DOT 5 silicon fluid.
However, some brands use the name "Super DOT 4" for their high boiling point fluids, others just produce DOT 4 which blows everything else away and barely mention boiling point.

The motorsport guys I know swear by motul, I have boiled DOT4 from my mountainbike brakes, but now with bigger rotors they simply turn purple and don't boil.

Originally Posted by procrastination inc

DOT 4 was invented for those who drive their Auto with the left foot resting on the brake.

Dot 4 is what I'm using and I dont ride the brakes and it boils all too easy, do you know of a Brake fluid that has a higher boiling point than 275C, Regards Frank.

Try Wilwood disc brakes,

Wilwood Engineering - Brake Fluid

WILWOOD Hi-Temp° 570 RACING BRAKE FLUID:
Wilwood’s specially formulated Hi-Temp° 570 Racing Brake Fluid has a minimum 570° F dry boiling point to withstand the severe heat requirements of automotive racing. Hi-Temp° 570’s low viscosity allows easy bleeding of your brake system, eliminating aeration of the brake fluid caused by foaming due to excessive pumping of the pedal.

OR

EXP 600 PLUS SUPER HIGH-TEMP RACING BRAKE FLUID:
EXP 600 Plus is a highly refined blend developed for extreme performance under the high heat and extreme pressure of professional motorsports.

What’s in a number?
EXP 600 Plus has tested to 626 degrees F with a wet boiling point of 417 F. These numbers far exceed any DOT or SAE specifications.

We use the first one in our offroad Pro-Class buggy...

how the hell are you guys driving them if your boiling off the brake fluid?

if you want much better than top end dot 4 (remeber some brands are better than others and 275 degrees is the minimum boiling point you should have for dot 4 brake fluid) then you need to goto the silicone stuff.


you have fun doing that now. you have to change just about every seal in the thing do make it work properly and reliabley but once its done you almost never have to change it.

and a little info on brake fluid from Wilwood...

Wilwood Engineering - Brake Fluid Tips

Pasted from their site...

BRAKE FLUID:
Due to the extreme operating temperatures of a high performance brake system, standard off-the-shelf brake fluids are not recommended. Of critical importance in determining a fluids ability to handle high temperature applications is the Dry Boiling Point and compressibility.

The Dry Boiling Point is the temperature at which a brake fluid will boil in its virgin non-contaminated state. The highest temperature Dry Boiling Point available in a DOT 3 fluid is 572 degrees F.

The Wet Boiling Point is the temperature a brake fluid will boil after it has been fully saturated with moisture. The DOT 3 requirement for wet boiling point is a minimum temperature of 284 degrees F.

There are many ways for moisture to enter your brake system. Condensation from regular use, washing the vehicle and humidity are the most common, with little hope of prevention. Glycol based DOT 3 & 4 fluids are hygroscopic; they absorb brake system moisture, and over time the boiling point is gradually reduced.

Wilwood does not recommend using DOT 5 fluid in any racing applications. DOT 5 fluid is not hygroscopic, so as moisture enters the system, it is not absorbed by the fluid, and results in beads of moisture moving through the brake line, collecting in the calipers. It is not uncommon to have caliper temperatures exceed 200 degrees F, and at 212 degrees F, this collected moisture will boil causing vapor lock and system failure. Additionally, DOT 5 fluid is highly compressible due to aeration and foaming under normal braking conditions, providing a spongy brake feel.

Whenever you add fresh fluid to your existing system (never mix fluids of different DOT classifications), it immediately becomes contaminated, lowering the boiling point of the new fluid. For maximum performance, start with the highest Dry Boiling Point available (try Wilwood Hi-Temp 570 Racing Brake Fluid), flush the system completely, and flush it regularly, especially after severe temperatures have been experienced.

HTH

AP Racing

Brake Fluid

AP Racing Brake Fluids have been developed specifically for use under the arduous conditions encountered at the highest levels of motorsport.
All AP Racing Brake Fluids are compatible with all hydraulic brake systems designed to conform to S.A.E. J1703 requirements.
AP 600 Brake Fluid is intended for competition use only. AP 551 can be used for either competition or road use.

The new AP Racing PRF 660 has been developed for use in extreme high temperature racing conditions. Conforms to and exceeds FMVSS 116 DOT 4 and SAE J1703 and J1704.

AP Racing Formula DOT 5.1 Brake Fluid conforms to S.A.E. J1703 specifications and is ideal for High Performance Road Applications, Competition and Track Days.

All AP Racing Brake Fluids are Polyalkalene Glycol Ether based and are not a silicone based fluid. AP Racing do not sell and do not recommend using a silicone based brake fluid with any of its products. More Information.
Colour variations may occour in AP 600 brake fluid due to its manufacturing process.
This has no effect on the quality and performance of this product.

Originally Posted by Sandtoyz

AP Racing

Brake Fluid

AP Racing Brake Fluids have been developed specifically for use under the arduous conditions encountered at the highest levels of motorsport.
All AP Racing Brake Fluids are compatible with all hydraulic brake systems designed to conform to S.A.E. J1703 requirements.
AP 600 Brake Fluid is intended for competition use only. AP 551 can be used for either competition or road use.

The new AP Racing PRF 660 has been developed for use in extreme high temperature racing conditions. Conforms to and exceeds FMVSS 116 DOT 4 and SAE J1703 and J1704.

AP Racing Formula DOT 5.1 Brake Fluid conforms to S.A.E. J1703 specifications and is ideal for High Performance Road Applications, Competition and Track Days.

All AP Racing Brake Fluids are Polyalkalene Glycol Ether based and are not a silicone based fluid. AP Racing do not sell and do not recommend using a silicone based brake fluid with any of its products. More Information.
Colour variations may occour in AP 600 brake fluid due to its manufacturing process.
This has no effect on the quality and performance of this product.

I did some ringing around, Shell tech line. Castrol tech line, and came up with some interesting Facts, as above, Shell Super Dot 4 has a Dry Boiling Point(DBP) about 10c above dot 4, Castrol Response is around 286C (DBP), but the Wet Boiling Point WBP for both is below 200C, Castrol SFR is around 300C (DBP) but it's (WBP) is about 275C, but costs near $100/litre. So I'll give Castrol Response at about $20/litre a go, Thanks for the info, much appreciated, Regards Frank.