[Hops]

Originally Posted by m3bs

European makes have always specified DOT4, but they also call for periodic fluid changes every 2 or 3 years. In deference to lazy American owners, the domestics call for DOT3 and don’t mandate fluid changes. Supposedly the real world performance of the DOT3 degrades less over time. I’ve read a number of technical papers on the subject.

in my previous 128i bmw I did the brake fluid changes myself, it's funny the bmw factory dot 4 fluid i bought at the dealer is significantly cheaper that the factory dot 4 fluid for the Camaro. But i will say that's probably the only thing that's cheaper... LOL

[TrackClub]

Originally Posted by m3bs

European makes have always specified DOT4, but they also call for periodic fluid changes every 2 or 3 years. In deference to lazy American owners, the domestics call for DOT3 and don’t mandate fluid changes. Supposedly the real world performance of the DOT3 degrades less over time. I’ve read a number of technical papers on the subject.

It might be overkill, but I push at least 1/2 a liter through my brake system before every track weekend. The plan has served me well for 30 years now. I also have a lot of used brake fluid to get rid of somehow......

Yep the Vette manual as highlighted above calls for 3 yr intervals as well. And yep, i suspect there are lots of old vehicles out there with original fluid in NA...

I used to bleed Willwood 570 often. But with SRF it comes out as clear as it goes in (pretty much). So every 10 days or so seems adequate to me. But won't argue with higher frequency (of any fluid). Cheers!

[AD17SS1LE]

Originally Posted by TrackClub

Thanks for posting this link. Ive seen it before but could not find it. As i had suggested before, there is more than just temp specs to consider when selecting a fluid and this link speaks to it very well. All test parms play a role.
There was a good article on this from Willwood, but i cant find it anywhere either.

You also make a very good point about the wet vs dry boiling points. In addition to it, DOT4 absorbs moisture much faster than DOT3. That's why it is unsuitable for long term use vs regular OEM fluids. Of course i am not suggesting using an OEM for track, but that's something to keep in mind.

Looking at the posted tests, looks like SRF is worth every penny. Given that it lasts a whole season with just a mid season bleeding, it is my choice anyway.
It seems very stable and when we bled it last year after about 10 track days, it came out looking hardly any different than new. This was my experience anyway, with stock pads, so nobody should take it as a scientific proof of anything and make their own educated choices. Albeit a very fast and a very prolific top driver here (Provoste) expressed a very similar experience on his car (with DTC60 pads).

Lastly, while BRF600 may work for some, it appears that it won't for others. Clearly you had managed to pass its limits yourself even with stock pads (!!!), the Supra driver boiled it suddenly and catastrophically and Sam may have run it as well (with very aggressive pads) albeit it is not clear what exact fluid he called "600", or what really happened.

Cheers!

The torque rt700 got bought out by pro speed rs683, I started out using the torque rt700 then had to go to pro speed rs683. I now use castrol srf. I have not had any issues using any of these fluids. have stock rotors and use stock pads. Here is a good link to compare brake fluids, don't look at dry temps as they don't matter. The wet temp is what you need to reference.
https://www.lelandwest.com/brake-flu...ow=1&SF=4&ST=2

[TrackClub]

Originally Posted by AD17SS1LE

The torque rt700 got bought out by pro speed rs683, I started out using the torque rt700 then had to go to pro speed rs683. I now use castrol srf. I have not had any issues using any of these fluids. have stock rotors and use stock pads. Here is a good link to compare brake fluids, don't look at dry temps as they don't matter. The wet temp is what you need to reference.
https://www.lelandwest.com/brake-flu...ow=1&SF=4&ST=2

An updated chart: great! I have an older version. Interesting RBF600 is no longer listed...

[LESS1]

As long as we are discussing brake issues, I found this.



Jump to min 8:20 and hang on for a wild ride due to a defective cheap aftermarket brake rotor. Certainly not the best wave to cut costs. Turn 1 at Summit Point Main is very fast for some cars/drivers, I regularly hit 140 - 145 before braking into turn 1. Really glad this gent didn't get hurt.

[JamesNoBrakes]

Originally Posted by TrackClub

Yep the Vette manual as highlighted above calls for 3 yr intervals as well. And yep, i suspect there are lots of old vehicles out there with original fluid in NA...

Which would do just fine, until pushed towards the limit...

[cdrptrks]

Originally Posted by AD17SS1LE

The wet temp is what you need to reference.
https://www.lelandwest.com/brake-flu...ow=1&SF=4&ST=2

Thanks for sharing. Wet boiling point is when there is 3.7% water in the fluid. If the boiling point vs. % water content chart is similar for other DOT4 brake fluids like RBF600 then a 600°F dry boiling point fluid would still have a boiling point of about 482°F after 1 year in service in my personal experience which is the longest interval I have seen allowed on Texas HPDE inspection forms.

I have also heard that the water % is higher near the calipers after a few track days but not sure if there is a real source to confirm that.

I posted in a track group Facebook discussion recently that I had done 10 track days in about 9 months on Stoptech 600 fluid that has never been bled with stock pads and GM plastic track brake cooling deflectors with no issues and some people were very concerned. The reservoir tested at less than 1% water content before the last event and I plan to test the water % of the fluid from near the calipers when I do my next full flush soon with about 1.25L of new fluid.

For the most recent track day it was 95°F at Eagles Canyon and I was having issues with the stock tires overheating and losing some grip rather than brake fluid.

[Mountain]

Originally Posted by cdrptrks

Thanks for sharing. Wet boiling point is when there is 3.7% water in the fluid. If the boiling point vs. % water content chart is similar for other DOT4 brake fluids like RBF600 then a 600°F dry boiling point fluid would still have a boiling point of about 482°F after 1 year in service in my personal experience which is the longest interval I have seen allowed on Texas HPDE inspection forms.

I have also heard that the water % is higher near the calipers after a few track days but not sure if there is a real source to confirm that.

I posted in a track group Facebook discussion recently that I had done 10 track days in about 9 months on Stoptech 600 fluid that has never been bled with stock pads and GM plastic track brake cooling deflectors with no issues and some people were very concerned. The reservoir tested at less than 1% water content before the last event and I plan to test the water % of the fluid from near the calipers when I do my next full flush soon with about 1.25L of new fluid.

For the most recent track day it was 95°F at Eagles Canyon and I was having issues with the stock tires overheating and losing some grip rather than brake fluid.

Essex Brakes put out some interesting tech posts in the Corvette forums a bit ago and I think also on their website about wet boiling point and how much of a real concern it is compared to dry boiling point.

In summary, the message was, yes, wet boiling point is important, but it should not be the main focus, as commonly thought, over dry boiling point. The amount of water, in which the industry test is done for ratings is actually quite a bit of water absorbed into the system. For a track enthusiast, you should be purging the system well before the water content...

The selling point with SRF is the ability to not have to purge the system and bleed the brakes as regular as you would with some other fluids (in other words: the thresholds are higher). I've ran Motul 600, Motul 660, StopTech 600, and Castrol SRF on race cars and track cars. A lot of experience with Motul 600 and StopTech 600 (and I feel like they are essentially equal if not the same). The ability to handle more heat with the Motul 660 vs 600 is noticeable in that the pedal is more consistent in hot sessions and the fluid seems less prone to getting air after hot session. I can say that SRF is really a nice fluid, as I did not need to bleed brakes as much (basically found I hardly ever needed to, even though I did) and the pedal never changed, but there is nothing wrong with the other fluids I've used.

[TrackClub]

Originally Posted by Mountain

Essex Brakes put out some interesting tech posts in the Corvette forums a bit ago and I think also on their website about wet boiling point and how much of a real concern it is compared to dry boiling point.

In summary, the message was, yes, wet boiling point is important, but it should not be the main focus, as commonly thought, over dry boiling point. The amount of water, in which the industry test is done for ratings is actually quite a bit of water absorbed into the system. For a track enthusiast, you should be purging the system well before the water content...

The selling point with SRF is the ability to not have to purge the system and bleed the brakes as regular as you would with some other fluids (in other words: the thresholds are higher). I've ran Motul 600, Motul 660, StopTech 600, and Castrol SRF on race cars and track cars. A lot of experience with Motul 600 and StopTech 600 (and I feel like they are essentially equal if not the same). The ability to handle more heat with the Motul 660 vs 600 is noticeable in that the pedal is more consistent in hot sessions and the fluid seems less prone to getting air after hot session. I can say that SRF is really a nice fluid, as I did not need to bleed brakes as much (basically found I hardly ever needed to, even though I did) and the pedal never changed, but there is nothing wrong with the other fluids I've used.

Well said. Yet i will take a fluid that shows virtually zero decomposition after 10+ full on track days anytime.
Cheers!

[Mountain]

Originally Posted by TrackClub

Well said. Yet i will take a fluid that shows virtually zero decomposition after 10+ full on track days anytime.
Cheers!

Originally Posted by Essex

The ‘wet boiling point’ is simply a test conducted on brake fluid to determine how quickly it will decline over the course of its service life. The brake fluid is exposed to a humid atmosphere for a specified period of time, after which the boiling point is measured. Originally the test was a rough approximation of a brake fluid’s boiling point after two years installed in a vehicle, at which point the fluid would contain approximately 3.7% water by volume. The wet boiling point test was devised for fluid used in OE road vehicle applications, where the owner typically pays little attention to the brake system once the vehicle leaves the dealership. That minivan parked in your driveway...the one with the goldfish crackers wedged in the rear seats. That's the relevant vehicle with regards to wet boiling point. When you're on the way to Walley World with six kids and all your gear, you don't want to experience brake fade because of a low wet boiling point.

Originally Posted by Essex

Now that we understand why wet boiling point isn’t terribly relevant for racing brake fluid applications, let’s look at what actually matters for superior fluid performance.

High Dry Boiling Point- The temperature at which the brake fluid will boil when fresh from the bottle. For racing or track cars that are frequently serviced, the brake fluid in the car should always be relatively fresh. Having a high dry boiling point means that the fluid has a high resistance to vapor lock, which is when the fluid reaches its boiling point, transforms into a compressible gas, and results in a long brake pedal. AP Racing R4 has one of the highest dry boiling points of any brake fluid available today.

Low Viscosity- A fluid with a low internal resistance to flow is described as having a ‘low viscosity’. The lower the viscosity, the more readily the fluid flows from the master cylinders, through the brake lines, into the ABS modulator (if equipped), and throughout the brake calipers. In other words, a fluid with a low viscosity provides the most rapid actuation of all brake system components, and AP Racing R4 has an extremely low viscosity.

High Lubricity- For two fluids with a similar viscosity, the one with the higher lubricity will result in less wear of the brake system’s moving parts. AP Racing Radi-CAL R4 has enhanced lubricity, extending the service life of your costly brake components.

https://www.essexparts.com/news-blog...ng-brake-fluid

Can't find the Corvette forum post, but here are some from a Porsche forum of the same conversations on brake fluid:
https://rennlist.com/forums/991-gt3-...srf-wtf-2.html

A reason I went to Motul 660 was due to the high dry boiling point and low-viscosity/applicability to ABS. Ferodo fluid was my second choice, but Motul was easier for me to source. SRF is sometimes hard to find.

[TrackClub]

Originally Posted by Mountain

https://www.essexparts.com/news-blog...ng-brake-fluid

Can't find the Corvette forum post, but here are some from a Porsche forum of the same conversations on brake fluid:
https://rennlist.com/forums/991-gt3-...srf-wtf-2.html

A reason I went to Motul 660 was due to the high dry boiling point and low-viscosity/applicability to ABS. Ferodo fluid was my second choice, but Motul was easier for me to source. SRF is sometimes hard to find.

If i could not get SRF id likely go with 660 as well.

Interesting musings from Essex on their product lines with SRF clearly as the target. Can't blame them

Yep R4 has a higher dry point but MUCH lower wet point and personally i will not discount the latter as irrelevant.
When independent study was done (posted above in one of the links) they also measured % of H02 present. Worthy a peek, as my memory tells me that number was never zero.

Their analogy as to how long it would take for fluid to absorb moisture is rather humorous, but completely unscientific. Besides, they are a reseller not a fluid manufacturer.

And one item that is completely missing is required bleeding inervals, which with SRF are very long.

I am positive that no Nascar, nor IndyCar team ever uses any of the fluids beyond a single race. Also, Cup cars at Daytona only brake going into pits etc.

NB for them to suggest R3 will do very well and compare it to RBF600 is not necessarily a vote of high confidence given some member (and the Supra guy) comments about the latter.

Just my musings. Cheers!

[NeverDie]

That essex parts blog entry is quite simply an advertisement for product and should only be treated as such, not as a resource for your research.

[TrackClub]

Originally Posted by NeverDie

That essex parts blog entry is quite simply an advertisement for product and should only be treated as such, not as a resource for your research.

+1

[Mountain]

Originally Posted by TrackClub

If i could not get SRF id likely go with 660 as well.

Interesting musings from Essex on their product lines with SRF clearly as the target. Can't blame them

Yep R4 has a higher dry point but MUCH lower wet point and personally i will not discount the latter as irrelevant.
When independent study was done (posted above in one of the links) they also measured % of H02 present. Worthy a peek, as my memory tells me that number was never zero.

Their analogy as to how long it would take for fluid to absorb moisture is rather humorous, but completely unscientific. Besides, they are a reseller not a fluid manufacturer.

And one item that is completely missing is required bleeding inervals, which with SRF are very long.

I am positive that no Nascar, nor IndyCar team ever uses any of the fluids beyond a single race. Also, Cup cars at Daytona only brake going into pits etc.

NB for them to suggest R3 will do very well and compare it to RBF600 is not necessarily a vote of high confidence given some member (and the Supra guy) comments about the latter.

Just my musings. Cheers!

I don't think Essex's point is necessarily wet boiling point is completely irrelevant. Just with a track car or race car it shouldn't be placed in importance over dry boiling point. Their comments are in respect to usage scenario.

With the "independent study" are you speaking about the Torque, the manufacturer of the Torque RT700 DOT 4 fluid, study? What percentage water did they test to? What is their test procedure?

The Motul manf spec numbers are off (i.e. probably old data)? Motul 600 is 594F/399F and 660 is 622F/399F. Viscosities are off, too, but close enough.

Bleeding interval... I agree is great to know, but, honestly, it's one of those things for a car to be tracked/raced a person should be checking this regularly... Outside of that, it's a nice margin of safety item.

The big advantage of SRF is being able to keep that fluid in the system for a year plus and not have to worry about the fluid degrading. Brake bleeds are something that still be checked regularly, although you can probably get away with less frequency than most other fluids.

A lot of people act like if you don't use Castrol SRF, that's a problem. My position is not that it is not a good fluid. My position is it isn't the only fluid to use.

Originally Posted by NeverDie

That essex parts blog entry is quite simply an advertisement for product and should only be treated as such, not as a resource for your research.

And the Torque one shouldn't be considered one too?

Maybe I missed something posted about a study examining the rate of water absorption by DOT 3 or DOT4 in a sealed, modern vehicle system?

Is it stated (I don't see) or are we assuming the Torque experiment tested the brake fluids directly?

DOT/FMVSS equates 3.7% for 2 years in sealed vehicle system, and that number is derived off older automobile systems (70's). The standard does not test, directly, a specific brake fluid in question - it uses a reference fluid, like Torque states.

Originally Posted by Torque

A typical high performance DOT 4 fluid in a high-humidity environment will absorb as much as 4.5-5.0% moisture in as short a period as 2 weeks if not kept in a tightly sealed container.

https://www.federalregister.gov/docu...e-brake-fluids

Thttps://www.govinfo.gov/content/pkg/CFR-2012-title49-vol6/xml/CFR-2012-title49-vol6-sec571-116.xml