Two questions. Has anyone changed to VP 622 for their track brake fluid? Also, if you have changed to any high performance brake fluid for the track, did you switch back to GM fluid as the track prep guide says or did you keep the high performance fluid in the system? Since it is DOT4 fluid, I don’t see a reason to need to change back.

 

I'm curious what you're using at the track to swap brake fluid since the easier method using vacuum is no longer what you want to use on the C8's electric brake booster? Having to get a second person to pump the brakes brings me back 30 years to my Dad's garage and I never really liked the pressure I thought I was increasing on the plastic master cylinder when I had a couple of BMW's and was trying to use that Motiv type bleeder.

 

I dont switch back. Like you said they are DOT 4 fluids as well and both Motul and Castrol have advised me their fluids are good for a year without getting too much moisture in them which is longer than i'd go anyways.

 

In the one video I have seen of a shop doing it, they use a pressure container connected to the fluid reservoir, put it under pressure and then open the bleeds. The GM shop manual has additional instructions. Disconnect the battery, disconnect fluid level sensor, and then disable the brake booster using the diagnostic computer. That third part is a bit difficult for most home mechanics. I would not swap at track. You can drive on roads with a HP dot 4 fluid. I don’t plan on swapping at all. The original GM service bulletin says it is “recommended” to change back before driving on public roads. Seems like CYA. A DOT 4 fluid, even HP, should be legal on public roads. My dealer flushed mine with the HP fluid.

 

I just swapped for Castrol SRF and will run it on the street and track. We disconnected the battery and did the old fashioned 2-person bleed and it worked perfectly. No extra tools or process required.

 

I had Castrol SRF substituted at the dealership as part of pre-delivery prep, and have left it in there since (less than a year).

 

How many bottles did you need to bleed the system, i haven't seen any conclusive info and want to make sure i order enough for when i get it done on my car. Was 2 Litres enough?

 

Hello!

Although the Motul 600 (and even their more expensive, shorter service life Motul 660) are exceptionally good brake fluids, they are actually second and third in performance behind Castrol SRF. If you compare product spec sheets (links provided below), you'll see that Castrol SRF has a higher dry and wet boiling point. And what is more exciting, is that is rated to stay far above the necessary point, for up to 18 months. This means one flush at the start of each season and you'll be good for the entire season. I found the best price here:


Links to products' specifications:

Motul 600 (dry 594 F / wet 399 F): https://s3-eu-west-1.amazonaws.com/motul-production2/images/product_descriptions/technical_data_sheets/2635/RBF_600_Factory_Line__28GB_29.pdf?149201 6152

Motul 660 (dry 622 F / wet 399 F): https://s3-eu-west-1.amazonaws.com/motul-production2/images/product_descriptions/technical_data_sheets/2636/RBF_660_Factory_Line__28GB_29__281_29.pd f?1492016152

Castrol React SRF (dry 608 F / wet 518 F): http://www.goldfren.cz/_download_news/srf_en.pdf

Some people are highly recommending Prospeed's brake fluid.

I got the numbers from Prospeed RS683's website, see: http://rs683.com/abcs-of-brake-fluid/brake-fluid-chart/ .

For me, the "wet" boiling temperature is most important. A few other "race only” fluids start with a slightly higher "dry” temps (temps beyond our requirements) but degrade quickly and terribly with exposure to moisture. This is okay for race-teams that flush the fluids for every event.

Prospeed's big push is their claim of a very low (1%) dissolved oxygen, which contributes to a firm pedal. They suggest some of their competitors have 5% dissolved oxygen. I'm a little suspect that this is marketing hype, right along with their girls in skimpy clothing, corporate jets, and Lamborghinis. Maybe their 1% is good compared to Kmart's DOT 3, however if their 1% was truly unique in the world of high performance brake fluid, they should disclose this information on their comparison chart as well.

Prospeed RS683: dry 583 F / wet 394 F

Castrol React SRF: dry 608 F / wet 518 F

What concerns me with the Prospeed and the others is their 33% reduction in boiling point after becoming wet, and not knowing when it is wet! On the other hand, Castrol SRF only degrades 15% when wet. Castrol suggests in normal use, it will be dry enough track use for 18 months. So I feel very comfortable with one flush per season because even when wet, it is at 518 F. By the way, our calipers don’t even reach 518 F during the heaviest of use.

In conclusion, I haven’t been able to find a brake fluid, at any price, better than Castrol SRF!

 

Good information. I am currently running VP622 with 622 dry and 399 wet. What I don’t have is their recommendation on how often to flush.

 

Thank you, Island_Hopper. So the 622 degree F is far higher than we will likely need however the 399 is likely to prove inadequate.

 

399 wet is the same as the commonly used Motul 660. If you let it get that wet, it could be a problem. Will be changing twice a year and my car stays in a dehumidified garage when not being driven.

I will look into the Castrol. Their wet BP is almost too good to believe.

 

Sorry for the delay, yes -- less than 2L for the flush.

I tracked my car this past weekend and had excellent results with the OEM brakes with SRF. I managed to burn through a complete set of pads, though!

 

Wet boiling point might mean something if you were going to change your brake fluid every 5 years, maybe. But the real important thing is the Dry boiling point, where for road course use, higher is better.

Check out the top of the line AP Racing fluid. Higher Dry boiling point stats than just about anything else, and cheaper than SRF.

 

For me, considering all the other expenses that surround a track event, I'm happy to pay the little extra cost for the Castrol SRF because I can depend on it for the full 12 month season with margin to spare. Castrol says it takes 18 months before it's wet (and its wet is still an impressive 518 degrees F). By the way, one liter is all you need for a full flush.

 

We've had Endless RF650 in the shop car for nearly 3 years now with zero issues.

 

I use Motul 660, i flush it once a year. Havent had an issue in >5000 track miles.

 

I run Endless in my Supra and have had great results as well. I wouldn't hesitate to run it in anything. Do you guys do any periodic bleeding or just set it and forget it?

I went to SRF just due to availability and it's pretty much guaranteed to be in the pits at any event.

 

We've always periodically bled on earlier generations but with this car we just set and forget. We were surprised at how well it held up over time.

 

I want to pressure bleed because I don't have a second person really to help me with the 2-man method.
I can't get my pressure bleeder to work though because the crappy reservoir cap seal leaks fluid everywhere. Does anyone here use a pressure bleeder and have a source for a cap that actually WORKS???

 

I'm anxiously waiting to learn of a better method that people are using to bleed their brakes on these electronic brake boosters. I had just found a nice pneumatic tool for bleeding brakes just a couple of years ago but now all three vehicles in my garage have electronic brake boosters. I used to use a Motiv brake bleeder that I would have to attach to the brake fluid reservoir and then add a pressure to it, but I never liked doing it that way. Very curious what the dealers and other pros at shops are using.