Brake Fluid

[Greg_S]

Ive just found some more details on castrol products

Castrol Super Response DOT4 Specs

PERFORMANCE

SAE J1703 (Current)

ISO 4925

FMVSS 116 DOT 3 & DOT 4

JIS K 2233

TYPICAL CHARACTERISTICS

Dry Boiling Point ºC 280

Wet Boiling Point ºC ca 190

Viscosity at -40ºC, cSt 1200

Viscosity at 100ºC 2.6

pH 7.2

[Greg_S]

also the Motul RBF 600

http://www.opieoils.co.uk/performance_lubricants/pdf/motul/RBF600racingbrakefluid.pdf

312 C Dry boiling point
216 C wet boiling point

works out at £14.08 a litre from here

[Chris M]

Did you look at the millers R300+ stuff Greg, it here in this thread http://www.s2forum.com/forum/showthread.php?t=13221

I got it from my local Millers store. Running it in the Golf and did in the S2.

[dan_b]

The spec for the Millers stuff is in this thread in my rather overly-long post above!

[oilman]

There seem to be some generalisations here:

Not all DOT 4's are the same, there are stock ones, better ones and racing ones.

DOT 5.1 is a longlife fluid that will not outperform serious Racing Dot 4's in the short term it will just last longer.

Products like Motul RBF 600 will outperform any DOT 5.1 but you need to look at the application. For "track addicts" a Racing DOT 4 like Motul RBF 600 is the way to go, just look at the data on the boiling points.

http://www.opieoils.co.uk/performance_lubricants/pdf/motul/RBF600racingbrakefluid.pdf

http://www.opieoils.co.uk/performance_lubricants/pdf/silkolene/PRO%20RACE%202000%20-%204%20Wheel.pdf

For a road car where longevity is the aim then DOT 5.1 is the way to go.

http://www.opieoils.co.uk/performance_lubricants/pdf/motul/DOT5.1BrakeFluid.pdf

Hope this clarifies.

Cheers
Simon

[Greg_S]

Simon, Im not sure we can use DOT5.1 fluid in the S2.

Do you know what the wet boiling point of the silkolene fluid is?

ta

[dan_b]

DOT 5.1 is perfectly safe for the S2 - it's DOT 5.0 that absoloutely must not be used in the S2 as it is a Silicone ester based fluid which is frankly not what our cars like.

@Simon - don't understand where you think I've generalised in this thread - I've stated and shown the various different BPs of different brake fluids and have also shown that some fluids absorb water more quickly than others, which means you have to change them more regularly to maintain performance. Maybe I waffled too much that's certainly likely! Certainly not all fluids are created equal, that's perfectly true.

I originally tried a "normal" DOT5.1 in my brake system when I converted to the RS2 brake setup and found that I was getting fade and it was actually forming a sort of sperm-like emulsion in the brake lines which can't have been good - swapped to the ATE Super and the fade, and the emulsion, went away.

Changing brake fluid every 12 months is something I would recommend - it's not hard to do and it maintains performance.

[oilman]

Simon, Im not sure we can use DOT5.1 fluid in the S2.

Do you know what the wet boiling point of the silkolene fluid is?

ta

It's 195DegC minimum.

You can use 5.1

Cheers
Simon