I think in my case the fluid was just old and broken down...has to be 10 years on the fluid so thats pretty impressive i hammer the foot brake pretty hard

CASTROL REACT fluid FTW...

I don’t think DOT5 won’t boil in our cars, I KNOW it won’t. Further the boiling point of 5 is not lower than 5.1

https://drr.infopop.cc/eve/foru...912/m/8237093186/p/1

quote:

Originally posted by SlyFox:
This is an interesting topic - it also set me to thinking about something like a NASCAR stocker or an Indy or F1 car that generates a ton of brake heat without boiling fluid. Maybe an added safety feature for you guys with big MPH dragsters would be cooling ducts to your brakes?

Mike, I like that idea. Maybe even a simple little deflector that would direct some additional airflow to the rotors.

I see data that shows DOT 5 and 5.1 both at 500 degrees vs. The 500° and 518° respectively that I see on several other sites. I am truly just curious why you believe the DOT 5 won't boil? Because you don't think you can ever achieve that temperature threshold under the conditions in the car or is there some technical reason I am missing. I don't claim to know it all that is why I am asking. I do remember that there are some exceptions to materials having a boiling point but silicone doesn't appear to be one of them. Just trying to have a rational discussion. Not interested in the One upmanship.

Fortunate to have a backup system! We have had numerous occasions where the fire trucks rolled because the carbon brakes ( all four ) were glowing big time. I don’t think...we had fade but I’ll ask Jeff.
Chute failed to deploy-
You have spring or air launch??

It all boils... at what temp is key..

Because I’ve been using it for many years in my cars and it’s the only brake fluid that when flushed looks like what went in
/what came out of the bottle. ALL the others smell burnt and look burnt after just one season.

It wouldn’t if it was clear like the rest an not purple

The older the fluid the easier it boils, it takes on moisture.
Dot
3-401 deg
4-446
lhm-480
5.1- 500 deg

Here is a temperature comparison from the same company.

American made

dot 5

https://www.maximausa.com/tds/misc/DOT%205%20TDS.pdf

same brand dot 5.1

https://www.maximausa.com/tds/.../DOT%205.1%20TDS.pdf

quote:

Originally posted by Canted Valve:

quote:

Air condition is essentially nothing more than a refrigerant in a closed system that is constantly cycling between a liquid state and a gaseous state.

Hey, Mr. Chemist. A/C system is a closed system. So why does ambient temperature and humidity affect gauge readings?

I'm not a chemist nor an HVAC repairman, but I did take Chem 101 as an elective in college.

I imagine that ambient temperature and humidity affect efficiency of condenser and evaporator, among other things. But that's not really the question - the question was, do brakes need to be bled after fluid boils, and I believe the answer is still "no."

Looks like there is quite a bit of variation on the boiling temperatures across brands and formulas. The data Curtis shared (thank you) is a big step up on the DOT 5 BP and I have no reason to not consider it factual. I would still argue that DOT 5 fluid will boil at its boiling temperature, that seems pretty certain.

quote:

Originally posted by BG7X77:
Looks like there is quite a bit of variation on the boiling temperatures across brands and formulas. The data Curtis shared (thank you) is a big step up on the DOT 5 BP and I have no reason to not consider it factual. I would still argue that DOT 5 fluid will boil at its boiling temperature, that seems pretty certain.

I agree that it will boil or there wouldn't be a boiling temp for it. LOL But whatever someone wants to argue. I just went and looked for data from a single source because you are correct, I saw varying temps listed.

Look at the volume change of water to steam.
It’s 1700:1 and occurring at 212F. The only way to keep the brake fluid water free, is change it. Everyone getting excited about the Dot Temp spec., when the issue is more about old neglected fluid with 2-4% water.
Change the fluid often, in humid areas and never run with thin brake pads. Sorry, but it’s about that simple.

Agree Paul, it’s all about maintenance.

That’s said, my point is unlike DOT 3, 4 and 5.1, DOT 5 never reaches its boiling point in our cars.

Few are diligent on maintenance like you Ed and it has paid off for you. Your recommendation to change the fluid may help many.
I don’t have the data to prove it, but my feeling is no dragrace car ever gets close to the dry or wet boiling points of any Dot class brake fluid.

quote:

Originally posted by adv ET 266:
Look at the volume change of water to steam.
It’s 1700:1 and occurring at 212F. The only way to keep the brake fluid water free, is change it. Everyone getting excited about the Dot Temp spec., when the issue is more about old neglected fluid with 2-4% water.
Change the fluid often, in humid areas and never run with thin brake pads. Sorry, but it’s about that simple.

This makes sense.

I had a chute fail to deploy at the Div.1 bracket finals in 2002. My car owner told me to pop the chute on the first run (normal for us), track manager stopped my pulling in the water and said to pop it. Employee in the waterbox and starter all stopped me and told me to pull it. 7.70's at 180mph, I pull the chute and nothing happens. It was very sketchy in the shut down as it was repaved a couple weeks prior and they had nothing but rain leading up to the bracket finals. Man, it was slippery and all I did was slide around. I manipulated the brake pedal and got got it slowed enough to make the turn and get the car stopped on the return road. Doesn't sound like much but it was a handful and all it wanted to do was lock the rear tires and slide them like I was on ice.

The chute had gotten wet when we pressure washed the car and we never took it out of the bag to let it dry. Then to make matters worse, I left the door down on the tralier and soaked the back of the car. So, the water logged chute ripped all the tethers when it deployed.
----------------------------
At my home track, I did the burnout and the brakes felt funny. I made the pass anyway and deployed the chute. The pedal went to the floor and was useless. Our hometrack had a very long shut down and was uphill so no real worries getting it stopped. Got it back to the pits and the pad material was gone from the brake pads and was just metal to metal.
----------------------------
Another time I was racing a buddies Monza at our home track. It was eliminations and again, the brakes failed in the burnout. Me, being the dumbass that I am, used the TB to stop the car in the beams while staging. Figured if he went red I had a chance to fix it and get back for next round. Well, him being faster, I had to leave first. So I let go on the top and matted it. When I saw him leave I lifted and fk me, no brakes at all. I coasted down track and up the hill. I dropped it in low and used the transbrake to stop the car at the end of the track. I had zero brakes on this run, the master cylinder was leaking and dumbed all the fluid out of it.
---------------------------

MORAL of my post: Don't be dumb like me but if you are, know what to do before it happens and you should walk away. If you gotta think what to do, it's probably too late to react.


Anyway, back to your argument over brake fluid boiling points and such.

For what it’s worth a NEW UNDERCOVER from Bill Fredrick will have CASTROL REACT in it....