Tim Webb

Sorry...Losing not Loosing!

bgiere

I use a mositure meter on mine and can tell you that brake fluid in a race car accumulates moisture very very slowly....Even my half empty cans of SRF show no accumulation after sitting on the shelf for six months....DISCLAIMER...I am assuming you do not let your car sit ouside in the rain and that you do not store your fluid underwater or in a swimming pool.

KaiB

Brant - enough data points to be absolutely confident about this?

Interesting and $$ saving perhaps. I've never let fluid go long enough to even begin to worry about it.

Tim Webb

Amazing that you are concerned about spending a half hour to bleed the system and spend a whopping $30, if that much, when an off caused by not taking care of the system can result in thousnads of dollars of damage.

If you are not taking the time to do propper maintenance on your car, you should not even be running it on track. Not only are you putting your car in harms way, but you are also putting everyone eles's that you run with.

bgiere

KaiB, in my particular case I've used the meter for more than 4 years...I check after each race weekend...Flush and refill the brake system at the beginning of each season. I do a nut/bolt and inspection on the car after every race and because we are swapping tires quite often I get a good look at the brake components after each session. I am not advocating letting fluid sit in your calipers forever by any means!! Change it out when needed, use a high quality racing fluid (not ATE IMHO) and keep a sharp eye on the components. I am backing out of this discussion...everyone's car is diferrent..Their climate is different and their driving style may be different. Do what is best for you and your safety.

KaiB

Brant, if that's the case, I shouldn't drink beer on race days until after 5:30pm.

What's the fun in that?

Jarez Mifkin

We typically bleed them at the end of every trackday. I like my brakes to work, and brake fluid is considered a consumable just like fuel.

BlueJay73

Thanks everyone.

I do bleed my brakes after every track event, and since I have a lift, I do a thorough inspection too.

I just wanted to see if I was wasting my time. From the responses, I may be overdoing it, but peace of mind is important to me, so I'll keep bleeding them after every track event.

Actually, since the ATE comes in 1 liter cans, I flush the whole liter through, instead of having an unsealed can of fluid on the shelf. I must say, the fluid coming out looks as clear as the fluid going in.

After I use up the ATE, I may go to Motul 600, although I've never had a soft peddle with the ATE.

One further question : Once fluid, even new fluid, gets really hot, is it degraded permanently, or does it return to its previous wet/dry BP and incompressability after it cools?

Thanks for the input.

rlm328

Once every 6 months to a year. I am using Motul. And unfortunately I drive it in the rain occasionally.

Bill Verburg

My 2cents
It depends, each cars requirements are different
not counting external factors like environmental conditions, the tracks and driver inputs the 2 biggies for brake fluid are
1) moisture uptake
2) heat uptake

As soon as the bf can is opened the fluid starts to absorb water, but it should last a season and you should pay attention to the wet specs not the dry

each car stresses it's brakes at different levels, some brake systems run much hotter than others in exactly the same use the hooter your brake system runs the better fluid wet specs you need and the more frequently you will need to change it
best fluid out there is Castrol SRF w/ 518 °F wet spec, but not every one needs it.

factory Cup cars use Endless RF650 424 °F and factory street fill is ATE 200 396 °F

my favorite because of the price point vs wet spec is Motul RBF 600 421 °F or Prospeed 683 394 °F(American made)

Just as an aside the 997 brakes that I've monitored have all tended to run very hot, almost double the temps that my 993RS brakes run

CCA

BlueJay, just to clarify, are you bleeding/flushing before the event and after or just after? If only after, I'd recommend doing it before the event instead. If both, then it is probably over kill.

I used ATE for a while with no problems, but like the pedal feel of Motul 600 better.

BlueJay73

I flush it after the event, not before and after. I track pretty frequently, so it doesn't stay in there very long. In other words, even though it is after the event, the brake fluid is still very fresh when I hit the track the next time.
I think I'll try Motul RBF 600 to see how that feels. Thanks for the input.

kurt M

I have been boil point testing brake fluid for about 10 years now. Not in a wide platform double blind controlled set up just the cars I deal with road and track, the stuff I have in my shop and some fellow driver’s cars. What I have found is water uptake is not as much an issue as people are led to think. That can you opened used 1/2 and set on the shelf in the garage a year ago? I bet it is good as new. The folks that seem to be the most strident about change it or toss it are not the folks that have true boil point testers. Takes 30 seconds to test.
I have 4 opened 1/2 used and shelved mix of metal cans and plastic bottles of brake fluid. One is a can of ate blue that is from spring of 2003. I found it on the back of a shelf some years ago and test samples of fluid from it and some other leftover containers of fluid when it have the tester out and think about it. It and the other containers all have my "opened on" date so I have good test cases to work with. In 10 years the ate fluid has lost about 8 deg of dry boil point. I also had a plastic bottle of cheap flaps brand stuff that is now 4 year old and it had lost 15 deg or so IIRC.

I live near Wash DC and the summers are about as humid and warm as you can stand. In the car I don't see more than a deg or 2 drop in dry boil point over the span of an entire year with SRF. I run SRF for a full year and replace it using a set method that does not involve older fluid deeper into the system. If you are worried about wet points the last thing you want to do is shove the stuff in the reservoir deeper into the system. You are moving what little water has been absorbed deeper into the system. My testing leads me to see that boil point drops, if any, are not in the calipers where the heat is. I remove the stuff in the reservoir before flushing and don't back flush fluid from the calipers if the car has ABS. I crack open the bleeder when pushing the pistons back for new pads. I do not run fluid further into the system from ether end. One end has more water, the other more contamination.

As for the rest of it I don’t wait to check over the car to just before go to the track again. I check it over right after the weekend. I want to have a head start on any issues found. No last min scrambles looking for a replacement part for the one that cracked or bent or got loose.

I found that the real bad fluid is in our street cars and/or in new to the track DE cars. I have tested some that was within a few deg of wet point and the fluid looked bad as well. I have never has a sample that looked OK but was wet. Every sample that was even close to saturated was also visually degraded. I think this is important. I have never had a significantly degraded boiling point sample that was not also visually degraded.

YMMV

raspritz

As noted above, different cars are different. So are different drivers.

A big heavy streetish car driven by a novice in a DE will burn through brake pads and brake fluid very quickly. A lightened racecar driven by a very experienced driver in amateur racing won't. I certainly don't change brake fluid or brake pads on my racecar after every race weekend. If I were a pro, and if I had a big crew and a big sponsored budget, of course I would. But I have no such delusions.

KOAN

I used to flush before every event, when I used ATE and Motul. I rarely felt a difference, but did it "to be safe", as well as to do a general check of other components. I'm amazed at how often I found other things that needed to be addressed.

Two years ago, I switched to SRF, and only flushed when I did pads or rotors ( maybe every 6-7 events). Never had any brake issues. I still check out the car on the lift between events.