Cole

I have a 951 that I take out to High Plains Raceway here in Colorado for lapping days.

Earlier this summer I managed to to boil my brake fluid by the second session. Pedal fell to the floor and did not come back until the brakes had cooled. Ruined a good lapping day.

Honestly, I have never put much thought into brake fluid. Probably because I have never had an issue with it. I put fresh stuff in earlier this spring when I did my torque tube rebuild. Just bought whatever was on the shelf at the auto part store.

Oddly enough there is a guy in our local Porsche club that makes RS683 brake fluid. So I picked up some of his fluid to give it a try at the next lapping day.

This was the ONLY change I made to my car from the lapping day where I boiled the fluid. (well, technically I added a roll bar to the car too)

I ran the whole day, every session without a single hint of the brakes going away.

Just thought I would share. (I figured I would take a fancy picture while bleeding the brakes)

Arominus

What were you running before? ate super blue/gold? or just some generic dot 3?

Also a heads up, the really high boiling point brake fluids tend to be very hydroscopic so you will need to flush the system more often.

Cole

I was just on generic dot 3. (think it was Prestone)

GTSilver944

The RS683 guy was saying something about super blue being not good last time I saw him (I think it was at cars and coffee). I didn't catch why he thought that. Maybe he'll chime in?

dykaar

Did the pedal go away during the session, or between sessions? If between, its heatsoak. I have a thermocouple on the brake pad, and drive around after each session to cool the brakes. That disk gets hot enough to boil the fluid and once the car stops moving there's little if any effective cooling. On my NA I boiled the fluid in the rear.

If it was during the session, then you either need proper cooling ducts, bigger brakes, or brake less. I never went as fast as when I warped the front rotors and couldn't brake hard. At the very least, remove the backing plate for track days.

Regards,

doug
Waterloo, Ontario Canada, eh


86 951
01 E320 (W210) 4matic Wagon
00 540i-6
94 855 turbo Wagon (sold in 09)
85 535i-5 (sold in 07)
76 300D (sold in 92)
83 944 (sold in 86)
I apparently only buy cars designated by numbers

Cole

The only thing I ever rememeber hearing about the Super Blue is that it is not DOT approved because of its color. I guess teh DOT standard defines the yellow/brown color of brake fluid.

Maybe there is more to it. Not my area of expertise.

It was during the session, but after I changed the fluid it lasted all day long.

mj951

I have used ATE blue/gold at the track and while there are better and more expensive brake fluids out there, for a DE event they work quite well.
Also, I can't tell from your photo but the addition of brake cooling ducts will help tremendously.

Cole

It has the factory "wings" on the back side of the calipers. I'm considering ditching my fog lights and running the ducts back to the brakes.

docwyte

I've used Super Blue/Gold for years without a problem. Brake cooling ducts help a lot.

You going to be at HPR this Saturday Cole? I'll be there with the LS1 944.

dykaar

Cole,

The "Holbert" style ducts replace the factory diverter with a proper duct, 3" hose and backing plate. No idea where you might find them now.

Regards,

doug
Waterloo, Ontario Canada, eh


86 951
01 E320 (W210) 4matic Wagon
00 540i-6
94 855 turbo Wagon (sold in 09)
85 535i-5 (sold in 07)
76 300D (sold in 92)
83 944 (sold in 86)
I apparently only buy cars designated by numbers

beentherebaby

FWIW- Some folks with Euro brand cars have reported issues over the years with the blue ATE - apparently from the dye acting up with the ABS system? I'm just stating what has reported. I have no firsthand knowledge of the actual effect the blue dye may or may not truly have on the brake system but the gold ATE which is the exact same fluid without the blue dye does not seem to be a problem. These fluids are good quality and have a relatively high boiling point.

In regards to the OP's fluid boil condition, it was probably the parts store low boiling temp fluid combined with moisture absorption and high altitude. A higher boiling temp fluid and bleeding before every track event to remove moisture is essential for track use. Brake cooling ducts are often required for regular track activities on most cars.

I have not tested the RS683 brake fluid though some folks say it is good. I have used Castrol LMA and most recently Motul RBF600 with excellent results for street and heavy track use.

Everybody has their favorite brake fluid. Some track junkies prefer the expensive Castrol SRF as it does not need to be bled frequently to remove moisture because it's wet boiling point is extremely high by comparison to other brake fluids.

YMMV

docwyte

My '01 Audi S4 definitely did not like the Ate Super Blue, clutch started squeeking shortly after putting it in and instantly got better when I flushed it out and replaced it with Motul RBF600.

All my other cars have been fine with it, so not sure what was up with that.

I haven't tried the new Prospeed fluid, I'm sure it's good stuff, but quite expensive. Even more than Castrol SRF...

Cole

No. Have other plans.

Sunday I am going to do the Porsche Club Autocross with the Cayenne

Jfrahm

Yeah the difference between DOT 3 and the good stuff is quite noticeable.

Scary spacers BTW.

-Joel.

Cole

Nothing scary about short spaces and long studs.