Let's talk about brake fluid

What do you use and why? I am cheap, and generally don't track my car, so I go with Super DOT 4. There is a part of me that wants to use racing fluid. I won't say what part. TRW Grand Prix 600 seems to be cheap and racy. What say you all?

Lots of choices, lots of opinions. I've settled on two that I put in all my cars, trucks and motos. ATE Typ 200 Goes in my trucks, motos, and cars that wont see frequent track days. $14/liter prime shipped on Amazon. Castrol SRF on my Porsches and other performance cars. Much more pricey at $67/liter shipped, but still in pretty cheap for once a year or so. Typ 200 boils at. 536� F dry (388.4� F wet), more than enough for any open track day if the system is freshly bled. Doesn't absorb water as quickly as many other racing fluids, which often compromise longevity for great dry temperatures. I don't have a problem keeping this fluid in my vehicles with several year change intervals and no bleeds if there not seeing track duty. SRF boils at 590� F dry, better, but where it really shines is that it is less hygroscopic (absorbs water more slowly), and when it does, it still has an outstanding wet boiling point of 518� F. Bottom line is that means less bleeds, fewer changes, and much less chance of surprise fade if you have a track day on a car that wasn't freshly bled. One liter is plenty for a full purge of the system with usually enough left over for a bleed as well. Also, when comparing prices, note that many fluids are sold in 500mL bottles, both of these are 1L

Last time I did a brake bleed, I used Pentosin.

Pentosin Super Dot 4, for comparison, has 509�F (329�F wet) boiling point... Not really a performance fluid by any definition.

I don't track my car. I use ATE 200. I agree with pfbz, it seems to hold up well over time.

Am I understanding the concept of brake fluid. Fluid for street use: negative - gets too hot on track days and boils positive - resistant to moisture bluid over longer period of time Fluid for high performance negative - short life span, susceptible to moisture positive - doesn't break down under extreme heat, safer for track use What do wise people use for DD doing a couple DEs a year?

For me its easy. Street and/or novice track, ate 200 For track, motul 600, srf, or endless. all will be more fluid than youll ever need

Quotes source post: 14403514

That's basically correct, but a bit more complicated. Street fluid that isn't too old and freshly bled is usually o.k. for most street tire track days... Old, unbled fluid will still work fine on the street, but likely boil under heavy track braking, cutting your track day pretty short (best case scenario). But the track or street fluid dilemma is exactly why Castrol SRF is worth the ~$70/liter. Performance equal most racing fluids, longevity of the best regular fluids. Plus a super high wet boiling point to allow it to work great even if it does absorb moisture! Good stuff. Spend the $70 and have the best street/track fluid there is. Note that SRF's wet boiling point is higher than Pentosin's dry boiling point... Most know this, but essentially this is what happens that causes issues with brake fluid: Pads contact rotors and generate lots of heat. Pistons contact pads. Fluid contacts pistons. If fluid next to the pistons exceeds the boiling point, it, well, boils. Boiling fluid creates air bubbles which remain, even after the fluid goes below boiling point. Fluid is incompressible. Gas (as in air bubbles) is compressible. So when fluid boils, you get spongy brakes and lose a direct connection between pedal and pads. As fluid ages, it absorbs moisture, reducing boiling point, aggravating the problem. To address these issues, you bleed and flush... Bleeding removes existing boil bubbles as well as the dirtiest, most contaminated fluid at the pad end of the hydraulic system, which absorbs moisture faster than in the middle of a brake line. Flushing removes all old fluid, restoring dry fluid throughout. Assuming of course you use FRESH fluid from a SEALED container,... Take an open container off the shelf and it might have as much moisture as the fluid you are bleeding or flushing...

Has anyone ever used Porsche Classic Brake Fluid DOT4? (It says it's "formulated for all Classic Porsche models thru 2004", because, yes, our 996s are now "classics.") It's a lot cheaper than Castrol SRF, with Pelican Parts selling it for $25 a liter and Suncoast Parts selling it for $20/liter . At that price, I'm assuming it's not for track-use.

Everything in my garage gets NAPA DOT 40 Heavy Duty. Race car, tow vehicle, and everything in between.

Quotes source post: 18075957

Dont bother. Ate200 for street. For cheaper track fluid, motul 600.

I have an unopened can of Brake fluid that's probably 10 years old. Would it still be good?

As long as its foil seal is unbroken it should be fine. Humidity/moisture is what ruins brake fluid. I spend too much on Endless rf650 but it feels great on the track/street so its worth it Amazon Amazon

Quotes source post: 18077087

Maybe, if it is in a tin can (test it, you can get a cheap brake fluid tester) if it is a plastic bottle, toss it...Plastic bottles can leach moisture through the plastic, and have a short shelf life..

Thanks, It's in a metal can.

Why have I been told that racing brake fluid should be changed twice as often (once a year) compared to street fluid (every two years)? Is it something to do with the fluid or mostly because if you are running racing fluid, you�re likely going to want to flush it more often anyway. Specifically talking about Castro�s SRF 600

It is more hygroscopic initially than lower grades of DOT brake fluid, I.e. the wet boiling point drops quicker. In order to actually have the higher boiling temperature you want the fluid fairly fresh.

Quotes source post: 18077187

Thanks, I guess I'll buy a tester. I still have a some cans of Ate Blue that I bought before they banned it and was wondering about shelf life.

Quotes source post: 18077805

Not exactly... Yes, many race-centric brake fluids have very high dry temps (fresh fluid), and markedly lower wet temps (older fluid). In addition, they tend to be even more hygroscopic then 'street' brake fluid (they turn from 'dry' to 'wet' more quickly). And flush intervals of not a year, but often a month, or even every event with many race fluids are called for. SRF is a bit of an exception in the race fluid spectrum. It has very high dry and wet temps, which is why it makes an excellent street/track fluid that does not require frequent flushing, because it retains high boil resistance even after being in the car a while and absorbing some moisture. True race cars might need the absolute highest 'dry' boiling point, and they don't care much about wet. They'll just flush every time. And if it avoids boiling, it's the right solution. For our street/track cars, we want significantly increased dry temps, but even more importantly, significantly increased wet temps since we do not want to flush frequently. Note that SRF 'wet' boiling point is still higher than Porsche OE fluid 'dry' boiling point. In other words, 'old' SRF is still less likely to boil than fresh OE fluid. . . Porsche OE 2005+ Brake fluid, 55.9520.100 Dry Boiling Point: 500F. Wet Boiling Point: 329F . Another comparison chart..

That’s a comprehensive list so it looks like the value leaders are the ATe200 redline motul and stop tech but the Castrol srf is the performer but at 2x the price of the others tough choice

Quotes source post: 18078003

Given the consumption cost for tires, brake pads & fuel for a few track days, let alone track fees, general wear and tear, safety equipment, etc., the extra $50 once a year for SRF fluid is even noticeable? And let me also say that if you have *ever* been at the track when someone has boiled their fluid and run off track, the $50 added expense seems comical to consider.

Quotes source post: 18078015

Yep. You pay up. Not to mention make sure your fluid is brand new and fresh for every track day. Ran out of brakes once and will never let it happen again.

Quotes source post: 18077919

Hope it's still good. Used it for years before the ban.

Why was it banned I used it in e30 m3 for years

Quotes source posts: 18078015, 18078110, 18078124

The only time I've had brake fluid boil was on the Pines to Palms Highway where it goes from 3000' to sea level in about a mile. Not fun. Me too.

Quotes source post: 18078131

Greenies banned it.

Quotes source post: 18078138

lol, it was 100% DOT. "greenies" don't know anything about brake fluid.

Quotes source post: 18078131

It wasn't some nefarious plot, and definitely not triggered by greenies... DOT specifies specific color for different types of fluid to help prevent using the wrong fluid, much like they dye different fuels different colors . DOT 3, DOT 4, and DOT 5.1: Colorless to amber. DOT 5 – Purple. Hydraulic system mineral oil – Green. . Super Blue, which is DOT 4, is definitely not colorless to amber. Closer in color to a DOT 5, which it definitely is not. I'm pretty sure the color requirement existed long before they stopped importing Super Blue, it was more. matter of enforcing something that had been in place for a while but not monitored. ATE Typ 200 is identical to Super Blue except for the golden color, which does conform to the standard.

Quotes source post: 18077919

Shelf life on this per manufacturer is 5 years. How old is this? Would you sell it?

I have been using RBF600. I flush before the season starts and then I bleed enough fluid after every track day to get fresh fluid into the calipers replacing that day's working fluid. I don't want to keep using fluid that has been cooking for hours. The fluid in the lines hasn't been exposed to extreme temperatures so should be in better condition. The drained fluid always looks a little off somehow. I figure that over the season I end up replacing the fluid twice, even though I don't do a complete flush in-season. I have been told the rbf660 has slightly better pedal feel than rbf600 due to slightly less compression. I have also been told that Endless 650 is the best for pedal feel and temperature resistance with SRF just behind.

Quotes source posts: 18078258, 18078227

I not sure how old it is but it's more than 5 years. Yup. You can see on the Ate Blue can where is says what standards in meets, it added "except blue colour".