Bleeding brake fluid after track event
06-07-2014, 11:17 PM
#32
Rennlist Member
No reason to flush/bleed the brakes if they didn't fade or feel funny. Racing/enduros put more stress on them than the time trials I do, but I easily get 4-5 events out of my ATE TYP200 brake fluid...
06-08-2014, 01:00 AM
#33
Slightly off topic, but I was going over my car after a DE, including bleeding the brakes. 
The outside brake pad, Pagid R29, on the passenger brake side was heavily worn on the front edge (about 3mm) but not on the trailing edge (about 9mm). Is there a way I could have installed incorrectly, or it is more likely the one of the pistons is not applying equal pressure?
In any case, a good reminder that checking the car between events is always a good idea and I will be keeping an eye on this for sure. And I did get some bubbles when bleeding the SRF fluid, so bleeding the brakes was worthwhile.
The outside brake pad, Pagid R29, on the passenger brake side was heavily worn on the front edge (about 3mm) but not on the trailing edge (about 9mm). Is there a way I could have installed incorrectly, or it is more likely the one of the pistons is not applying equal pressure?
In any case, a good reminder that checking the car between events is always a good idea and I will be keeping an eye on this for sure. And I did get some bubbles when bleeding the SRF fluid, so bleeding the brakes was worthwhile.
06-08-2014, 12:45 PM
#34
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Brake fluid is cheap and the process is not complicated.
BTW whilst I only race these days, I did the same for my DE/track days.
06-09-2014, 11:09 AM
#35
Rennlist Member
Can't say that I ever had an issue that caused me to miss track time. My car is setup to have the brakes last a long time and I'm not stressing them the way you racers are. There's simply no need to flush/bleed them every event. If I do it halfway through the season I'm being conservative...
04-19-2023, 10:59 PM
#36
Originally Posted by xuledywo
I have done 2 track days, plus around 5.000km with Pentosin Racing Brake Fluid (DoT 5.1)... how often do i need to change/bleed this fluid??? Thanks!!!
04-20-2023, 07:09 AM
#37
In the automotive world, it is suggested every 2 years. In the track world, it is typically required annually, but one region I run with requires it no more than 90 days before an event.
My car gets a pre-run and post-run inspection, but only gets a brake flush twice a year. Others I know do a “partial” flush after every event so to remove the brake fluid from the calipers because it may have been overheated. If you are tracking the car and adhering to either PCAs rules or the rules of the region and/or organization you are running with, you should be fine. I hope this helps
Cliff
My car gets a pre-run and post-run inspection, but only gets a brake flush twice a year. Others I know do a “partial” flush after every event so to remove the brake fluid from the calipers because it may have been overheated. If you are tracking the car and adhering to either PCAs rules or the rules of the region and/or organization you are running with, you should be fine. I hope this helps
Cliff
Last edited by chudson; 04-20-2023 at 07:10 AM.
04-20-2023, 09:43 AM
#38
Rennlist Member
I'd use how the brakes feel and what the fluid looks like more than time as an indicator, going no longer than what your region allows. If the region wants it flushed every 12 months, but the brakes don't feel right or the fluid has changed colors before that, then change it earlier.
I do an event a month on season, so maybe 4-6 days a seasons, using Castrol SRF. I find that if I flush the system before my first event, I'm fine for the seasons...
I do an event a month on season, so maybe 4-6 days a seasons, using Castrol SRF. I find that if I flush the system before my first event, I'm fine for the seasons...
04-20-2023, 10:49 AM
#39
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A 9 year bump.... nice!!
04-20-2023, 12:31 PM
#40
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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
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
Far too lazy to actually go through any testing on my own, and regardless of any flush or bleed between events, the car gets a thorough inspection every time.
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