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Brake Fluid and How offen do you bleed

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Was going to make a poll but there are a lot of options.

 

We run Castrol React SRF and bleed all 4 corners after every day in a 3 day track weekend if we have no problems (Never Happens) we will go through 1/2 a jug. 

 

I see a lot of teams using far less expensive fluids and just want to know what everyone runs and how often do you bleed all 4 corners. I know brakes isnt something to skimp on but i feel if we are bleeding every day we probably dont need to run SRF when Willwood 600+ is half the price and only a few degrees off boiling point.

 

 

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We used to run the illegal blue stuff.  Now we run the legal typ200 stuff.  Its like $12/liter.   E30 brakes get pretty dang hot and we don't have issues.

 

We will bleed them before a race weekend.  Then run a few DE's with no issues and no bleeding.

 

https://www.amazon.com/ATE-706202-Original-Racing-Quality/dp/B018GGV28S?th=1

Edited by Huggy
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I get used srf from race teams and run it through the car multiple times (using a filter). Maybe use 2 qrts a season. Bleed brakes with just a few pumps. If you aren't failing brake parts it looks as clean after a race as it did before.....

 

When i buy new fluid, i am in the same category as the listed options above. In the past used ate blue, i think many mid range fluids are more than good enough.

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I use Motul600, went all of 2018 (3 race weekends) on less than two pints of the stuff... I bleed an ounce or so from each wheel after a race weekend (if I remember to), and then refill the reservoir. 

Have never had issues.

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We run some hi temp high dollar stuff, damn hard to get old and not remember what the brand is but i will look it up and get back to you or you can ask me at Gingerman.

Flush the system once a year and that is it, unless we have an issue which is very rare.

Gray bottle with a yellow label and yellow cap, at least I can remember that 🙂

 

OK I looked it up AP Radi-Cal R3

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12 hours ago, Huggy said:

We used to run the illegal blue stuff.  Now we run the legal typ200 stuff.  Its like $12/liter.   E30 brakes get pretty dang hot and we don't have issues.

 

We will bleed them before a race weekend.  Then run a few DE's with no issues and no bleeding.

 

https://www.amazon.com/ATE-706202-Original-Racing-Quality/dp/B018GGV28S?th=1

 

I use to switch between blue and type 200, bleed till the color changed before every race.  Never had a fluid boil issue.

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On 8/14/2019 at 8:12 AM, Huggy said:

We used to run the illegal blue stuff.  Now we run the legal typ200 stuff.  Its like $12/liter.   E30 brakes get pretty dang hot and we don't have issues.

 

We will bleed them before a race weekend.  Then run a few DE's with no issues and no bleeding.

 

https://www.amazon.com/ATE-706202-Original-Racing-Quality/dp/B018GGV28S?th=1

 

Same in the Lexus.  We bleed before a race just to make sure, never have an issue.

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Was using a standard Dot 4, bled at the end of each day - no issues.  Probably bleed less than an ounce per wheel unless we see discoloration or have another concern. 

Have now switched to this:

https://www.jegs.com/i/JEGS/555/28073/10002/-1

 

Per a friend who is the buyer for this category at Jegs, CAM2 manufactures it.  Great price and a bit better wet boiling point than the Wilwood 570.

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Serious question here...

I always thought that bleeding the brakes was recommended due to the fluid getting moisture in it, and thus lowering it's boiling point. 

So, I figured you'd need to run enough fluid through the system to purge ALL of the old fluid.

Are the guys that are only bleeding an ounce from each corner really accomplishing anything?

(Or, the other reason to bleed would be if there was air in the system. I understand just doing an ounce or so for that.)

Edited by mcoppola
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11 hours ago, craig71188 said:

Was using a standard Dot 4, bled at the end of each day - no issues.  Probably bleed less than an ounce per wheel unless we see discoloration or have another concern. 

Have now switched to this:

https://www.jegs.com/i/JEGS/555/28073/10002/-1

 

Dude, you buried the lede... 4 bucks a bottle!!

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1 hour ago, mcoppola said:

Are the guys that are only bleeding an ounce from each corner really accomplishing anything?

Nope, nothing. As far as I know, you are absolutely correct here.

 

I wouldn't bleed them at all, except that it's a quick way to ensure there's no air in the calipers (I have no idea how air would have gotten in, and I have yet to find air during one of these routine bleeds). I buy the expensive motul 600 fluid which has an impressive wet boiling point. Even if it does get some moisture, it's still sufficiently resistant to boiling (I think).

Edited by enginerd
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^^^^same theory here on running the good stuff. (I also use the Motul 600, even though we've never had an issue, for the exact same reasons @enginerd stated.)

Thanks. I understand how it's a good check to see if anything unusual happened that would get air into the system.

Edited by mcoppola

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12 hours ago, mcoppola said:

Serious question here...

I always thought that bleeding the brakes was recommended due to the fluid getting moisture in it, and thus lowering it's boiling point. 

So, I figured you'd need to run enough fluid through the system to purge ALL of the old fluid.

Are the guys that are only bleeding an ounce from each corner really accomplishing anything?

(Or, the other reason to bleed would be if there was air in the system. I understand just doing an ounce or so for that.)

If we are not having problems (we typically have not), we will bleed a bit at each corner to look at the fluid and check for any air that may have worked itself in.  In this case, maybe an ounce or so at each corner.  If we have seen some actual degradation of performance or see any discoloration of the fluid, yes we would check the system further/move more fluid.  Between races we will do a more thorough brake service including moving enough fluid to clean the old out of the calipers if not flush most of the whole system.

 

Your results may vary.  If you are in a situation where the brakes are really abused (beyond their functional limits), first, add more cooling!  But if we were in a like case, we would be looking to flush that fluid from the system nightly!

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On Thursday, August 15, 2019 at 11:43 AM, the5 said:

Bleed every night, Gives you chance to get the wheels off the car and check for other issues as well

So what do you do in a 24hr race?

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My fluid of choice is Ferodo Super Formula, with AP Racing R3 as my #2.  Disclaimer: I'm very biased b/c its the brands we sell (but I also get to see actual/independent test data and not just label claims).  Anyway, flush once/year and bleed before each race.

 

@mcoppola  We recommend a quick bleed before an event on race cars/brake systems because the heat source is the back side of the caliper pistons.  Fluid on the back side of the pistons can start to vaporize before reaching the boiling point of the fluid and those tiny air gas bubbles remain trapped in the caliper (even with good fluids) until bled out.  There are tons of factors though...the caliper body material, the piston material/thickness, how thick are the pads, the pad friction coefficient, disc design, air flow, vehicle specs/speeds, etc, etc.  Spending 15-30min bleeding the calipers out before a race/track day is cheap insurance for the primary safety system.

 

Also, just because you open a bottle of fluid to use for bleeding doesn't mean the excess has to be discarded immediately.  Brake fluids are hygroscopic, obviously, but its over a pretty significant time and level of exposure.  It would take months of being open to the atmosphere in a humid environment to reach the moisture content needed to get the WBP of most fluids.  I'll keep a used/closed bottle stored in a dry place around for several months and do a few bleeds before I discard it.

Edited by Bremsen
engineers, lol
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On 8/14/2019 at 8:12 AM, Huggy said:

We used to run the illegal blue stuff.  Now we run the legal typ200 stuff.  Its like $12/liter.   E30 brakes get pretty dang hot and we don't have issues.

 

We will bleed them before a race weekend.  Then run a few DE's with no issues and no bleeding.

 

https://www.amazon.com/ATE-706202-Original-Racing-Quality/dp/B018GGV28S?th=1

 

I think I run the same and give two pumps each caliper before races. I was told in order to pronounce the name, your tongue would need to be cut out.

 

Bremsflüssigkeit

 

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