brake fluid (spin off of another thread)

[MCJUNKMAN]

That's very interesting... it sounds like you haven't had issues with the stock fluid yet then? I am trying to decide if I want to switch to another brake fluid or just bleed with the factory stuff now. I have always run RBF 660 in my cars without issue but everybody here seems to be reporting that its not great in these cars? I've got a HPDE at Mid-Ohio coming up and I know it will probably be pretty hard on the brakes.

Anthony, in your experience do you get any of the sponginess when in ABS with the torque?

Also as an interesting aside I wonder what kind of relationship Castrol has with Pentosin, because this "Castrol Dot 4 low temp" seems to have the exact same specs as the motorcraft and pentosin and is designed as a LV fluid.

http://msdspds.castrol.com/bpglis/fusionpds.nsf/files/90d5b00c9edb530680257a0500321cc6/$file/bpxe-8gwhqd_0.pdf

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[Norm Peterson]

More on this, the factory fluid meets a newer ISO Standard, Class 6. It is also designed for materials used in the modern brake systems...which when you look at some fluids they tell you don't use in systems with 'X' material. How do we know what's used for materials. The only fluid I found that meets this Ford Spec/ISO etc is Pentosin. I'm pretty sure they are making it for Ford because it has the exact same flash point. Its rated for 509F.

That's 'dry'.

Wet, it drops all the way off to about 340°F, and the apparently similar Castrol "React" stuff mentions a default change interval of 2 years . . . and that's for street driving where it's assumed you won't ever be getting anywhere near that 509°F dry boiling point.

Be careful.


Norm

 

[Optimum Performance]

That's 'dry'.

Wet, it drops all the way off to about 340°F, and the apparently similar Castrol "React" stuff mentions a default change interval of 2 years . . . and that's for street driving where it's assumed you won't ever be getting anywhere near that 509°F dry boiling point.

Be careful.


Norm

Point taken Norm. Dot 4's should be changed out every couple months anyway, Dot 4's absorb moisture at a higher rate. It's relatively inexpensive to have Ford do it. About $130 last time parts and labor.

Just grabbed this off of Stoptechs site:

DOT 4 is the grade applicable to most race engineered brake fluid in the world today, especially with regard to viscosity limit. Note that although the DOT 4 designation has a minimum dry and wet boiling point, a DOT 4 racing brake fluid may have a dry boiling point over 600F. Its viscosity is challenged, however, to be under the viscosity limit of 1,800 mm2/sec. Some claimed racing brake fluids exceed this important limit. Caution should be exercised if these fluids are used in race cars with ABS systems. This does not mean that DOT 4 fluids are necessarily better than DOT 3 fluids. Remember, the boiling points listed are minimums. There are certain DOT 3 fluids with higher boiling points than some DOT 4 fluids. The real differentiating factor is that DOT 4 fluid should be changed more often than a DOT 3 fluid, because of the effects and rates of water absorption.

We had yet to have issues with the Ford fluid. It's just a track day, no trophy's given. The audience of this post has a lot of members starting out. Our recommendation is stick with the stock fluid, but have it flushed before the event. We actually find it easier to pay flat rate at Ford, than doing it ourselves. Our time is more valuable elsewhere.

 

[grue]

side question - should have asked this a long time ago - do people use "bleed" and "flush" interchangeably? are they technically two different things?

so is mixing fluids a bad thing? say someone uses factory dot4 fluid and then right before a track day goes to the torque or motul etc... then goes back to factory after the track day, or, at the end of the season?

thanks,

 

[Norm Peterson]

I think you can consider bleeding to be a junior version of flushing . . . you won't necessarily chase ALL of the old fluid out with the new. But you'll at least get fluid that's in better condition down in and near the calipers where it really needs to be good.

If you mix better or higher temperature fluid in with the old, what you end up with will be less than what the good stuff is by itself. But probably better than the old stuff by itself.

If you bleed out about half a liter of old fluid before each track day, by about the third time you'll have essentially replaced all of the fluid. I have gone both days at a 2-day event on the same bleeding a couple of times, but don't think I'd go a third day.


Tommy - thanks for the 1800 mm^2/sec (aka cST) max viscosity mention. At least the Motuls are both under that.


Norm

 

[Optimum Performance]

side question - should have asked this a long time ago - do people use "bleed" and "flush" interchangeably? are they technically two different things?

so is mixing fluids a bad thing? say someone uses factory dot4 fluid and then right before a track day goes to the torque or motul etc... then goes back to factory after the track day, or, at the end of the season?

thanks,

Bleed is removing air, flush is total change. Mixing not a good idea, typically 3 qts will flush the system. The process of flushing involves bleeding out the old fluid at each wheel so that's where the words become inter-changed. One is a process to accomplish the other.

 

[Optimum Performance]

No Torque is not any harder on components than any othe fluid.

The issues I had with Motul is that it would fade very quickly, I had it actually boil on me.

I remember it very well. I was on my 3rd session of the day, I just bled the brakes since the fluid was already fading. So it was fresh.

As I come out of last corner before the main straight I tap the brakes and the pedal hits the floor.

That straight puts me at 120+, if I didn't tap my brakes I would have been a goner.

I pull into the pits and about 10 minutes later I have brake feel again but it is mushy.

I ended up researching fluid like crazy and narrowed it down to Castrol SRF and Torque.

I didn't use SRF because of what I read about it being a fully synthetic brake fluid. Which means you are not suppose to mix it with a standard dot4.

I went with Torque and never looked back. A year later I started selling it.

Anthony, looking at the specs of RT700 it is pretty close to the Class 6 ISO spec. Viscosity at higher temps vs. Stock fluid would be the only open question. If it is fairly close, it will become the go to fluid for these cars and BMW/Mini.

 

[grue]

thanks norm and tommy!

 

[Norm Peterson]

I used this on their site to compare.
http://torquebrakefluid.com/compare_torque_rt700_to_other_brake_fluids.html

I've tried to find out what or even where there is a spec for "high temperature stability" and what, exactly,

±5.4 + 1 ° that original BP exceeds 437 °F

even means.

With zero success, and I'm beginning to suspect a special character typo error. Does anybody really know what's going on here?


Reserve alkalinity sounds like a good thing, kind of a cushion against the fluid going acidic between bleedings/flushings. Maybe especially with pH numbers barely above 7.0.


Norm

 

[SteveW]

Good thread and glad the discussion about LV type fluids came up as that's a new one to me.

Having experienced brake fade and a slightly soft pedal after some track time a couple weeks ago I went with Stop Tech's STR-600 fluid. I'm still on the original Ford PP pads but the pedal was firmer and brakes held up great during some hard lapping yesterday. No fade yesterday.

I don't want to compromise the stability control/ABS performance and this stuff is meant for cars with it. Got two bottles from Tire Rack.

http://www.stoptech.com/products/str-brake-fluid

 

[apex15stangPP]

Guys had a chance to play with the stock fluid again last weekend. I can't say it was any better then before? I'm going to put my new rear pads in before I make another change. I may just need to go to a more aggressive pad to get the car to do what I need. I like the feel of the Carbotech AX6 pad, but it's leaving some performance on the table once hot.

I may try the RTR700 or stoptech, seems like users are getting what I'm looking for a hard pedal, which the stock fluid and motul didn't provide.

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