Brake Fluid Advice - track use
 

Hi there,


New track driver here - just wanted to ask a few questions about brake fluid...


1. How often do you change your brake fluid? Each season or after a certain number of track days?


2. I'm currently running the stock brake fluid in the stock brembos, I've only done 4 track days with them but I want to change the fluid for something better for track use. Amy suggestions? dot4?

3. How much should it cost to get done at a shop?


Thanks.






Thanks

I was happy with Castrol SRF. never boiled with AP racing sprint, stock power and 200 TW tires. So i just changed it start of the season.

I have never tracked the car but would use the car manual recommended DOT. I'm also thinking brake fluid should be good for at least a season or until the next rotor/pad swap.

OEM fluid is a waste of time at the track. And pads for that matter after your first track day, or less.

I've never had any problems running name-brand off-the-shelf parts store DOT4 (lately I've also used parts store Wagner DOT5.1). I'll start the track season with a full flush with new fluid. I take fluid with me to the track to bleed if necessary, but typically can get 6-8 track hours usage before having to bleed brakes.

RBF 600 or 660 is always a good budget bet. I flush mine in the beginning of the track season, then again halfway through.

Castrol SRF may be pricier upfront, but I ran it in the STI and would change it once a season. That wet boiling point is unmatched, which imo is the most important temperature to consider.

Highly recommend picking up a power bleeder with the appropriate master cylinder adapter. Makes the job a breeze.

https://www.motiveproducts.com/colle...r-bleeder-kits

Bears repeating:
Off-the-shelf DOT4 or DOT5.1 has never let me down at the track (even in a 550hp FD RX-7), lasts multiple track events (sometimes whole season for me, sometimes mid-season caliper-bleed required), inexpensive and readily available. Spend more if you want to, but most likely won't see any real benefit... Particularly "new track driver" in modestly-powered car with massive Brembo brakes!

1. How often do you change your brake fluid? Each season or after a certain number of track days?

Depends on the brake fluid you're running. I tried using Motul 600 at a suggestion from others and boiled it in 4 laps and I needed to bleed it pretty much after a single session (not day a single 20 min session). The Castrol SRF stuff I switched to I think can last me the whole season without bleeding. I'm at 4 track days and 4 time attack events on them and its still fine. You'll know it needs to be bled because your brakes feel like ass. I've found once you boil brake fluid it never really goes back to normal until you re-bleed.

2. I'm currently running the stock brake fluid in the stock brembos, I've only done 4 track days with them but I want to change the fluid for something better for track use. Amy suggestions? dot4?

Definitely upgrade brake fluid. Depending on how fast of a driver you are and how often you track something like Castrol SRF might be a good choice as it lasts a long time. If you only go once or twice a year ATE Typ 200 might be a better choice.

3. How much should it cost to get done at a shop?
I've not done it at a shop but I purchased a power bleeder for ~100 bucks and I just do it at home, takes like 10 mins.

DOT4/DOT5.1 should be enough.

RBF600/660 is an option but I find it expensive for my application. Mainly street/occasional track setup.

I bought 2 liters of motul 5.1 for something like $30CAD. 1 liter was used when I flushed the system.

I tried ATE200 once, and found it vastly inferior to off-the-shelf parts-store DOT4. Fresh fluid and had to bleed after one day at Watkins Glen in stock S2000 as the pedal was getting soft/spongy. Off-the shelf DOT4 lasted a whole track season without even rebleeding...

So to RE-repeat: off-the-shelf name-brand DOT4 or DOT5.1 is gonna be just fine for OP...

It seems you and I have had significantly different experiences with braking setups. I'm starting to be suspicious it's the S2000's fault! I've always run ATE200 (well, mostly super blue, same thing but blue and discontinued) and the only time I've had an issue with it I had a semi seized caliper (can't blame the fluid for having an issue with that!). Never needed to be re-bled and I think I swapped it after 2 seasons (but I only do ~5 events a season)

Still, I wouldn't say no to name brand dot 4/5.1. Motul stuff is too expensive for my tastes. 2-3x as much as ATE200 where I've looked.

Ha! Kinda impossible tho, no way with the same car, brake pads, and tires that the S2k coulda somehow thrown more heat at ATE200 fluid vs. off-the-shelf DOT4!

That was my one foray into "specialized" brake fluid. IMO it's overprescribed and overused and in most cases for tracked cars, totally unnecessary.

My approach is, as long as off-the-shelf DOT4 or DOT5.1 continue to work well with no discernable negatives, why bother with harder to get and way more pricey fluids? I think a lot of folks assume that ATE200, RBF600, etc. are just "better", but I don't know if that's even true. I think people just look at published wet/dry boiling points and assume higher number = always "better". But if they degrade and become more compressible under multiple heating cycles like the AT200 did in my case, that's not "better"...