DOT 5 fluid and Wilwood?

[zyzzyx]

I'm getting ready to pour the brand new DOT 5 fluid into my master cylinder of my 68 GTX and my Buddy down the street from me
who is a Hot Rodder just bought a Wilwood system for his steel bodied chopped something or other! Well, they say that using DOT 5
fluid will void their warranty! WTF? The car doesn't have ABS. They have a good scam going though, Wilwood XR Race Only brake
fluid, 16.9 fl. oz. $51.30 @ Summit Racing! Dry Boiling point of 645F. Polygycol-Ether based Non DOT4 fluid. Lotsa Hocus-Pocus!
So, I gotta ask why does Wilwood NOT want you to use DOT 5 in their stuff?

 

[pnora]

Did you read what they say and recommend.




Due to the extreme operating temperatures of a high-performance brake system, standard off-the-shelf brake fluids are not recommended. Of critical importance in determining a fluids ability to handle high temperature applications is the Dry Boiling Point and compressibility.
The Dry Boiling Point is the temperature at which a brake fluid will boil in its virgin non-contaminated state. The highest temperature Dry Boiling Point available in a DOT 3 fluid is 572 degrees F.
The Wet Boiling Point is the temperature a brake fluid will boil after it has been fully saturated with moisture. The DOT 3 requirement for wet boiling point is a minimum temperature of 284 degrees F.
There are many ways for moisture to enter your brake system. Condensation from regular use, washing the vehicle and humidity are the most common, with little hope of prevention. Glycol based DOT 3 & 4 fluids are hygroscopic; they absorb brake system moisture, and over time the boiling point is gradually reduced.
Wilwood does not recommend using DOT 5 fluid in any racing applications. DOT 5 fluid is not hygroscopic, so as moisture enters the system, it is not absorbed by the fluid, and results in beads of moisture moving through the brake line, collecting in the calipers. It is not uncommon to have caliper temperatures exceed 200 degrees F, and at 212 degrees F, this collected moisture will boil causing vapor lock and system failure. Additionally, DOT 5 fluid is highly compressible due to aeration and foaming under normal braking conditions, providing a spongy brake feel.
Whenever you add fresh fluid to your existing system (never mix fluids of different DOT classifications), it immediately becomes contaminated, lowering the boiling point of the new fluid. For maximum performance, start with the highest Dry Boiling Point available (try Wilwood Hi-Temp 570 Racing Brake Fluid), flush the system completely, and flush it regularly, especially after severe temperatures have been experienced.

 

[zyzzyx]

Yeah, I got all of that. Classic cars that don't race and go to car shows don't have these problems. As far as the moisture
is concerned, Silicone has NO affinity for moisture, so it doesn't get into the system as long as it's full of fluid. Since 1980,
The U.S. Army has mandated the use of SBF. MIL-PRF-46176. It is spec'd to reduce frequent fluid changes, brake failure,
and brake system deterioration over time caused by polyglycol based fluids.

So, my question was,
Why doesn't Wilwood want you to use SBF in their stuff even though they sell it????
Void the warranty? Why? I'm putting it in my car because I've used it in two bikes so far for 20+ years with no problems
but won't use it in my newer bike with ABS because of the foaming problem.
Not racing the car with it! No problem.

 

[Bird 426]

Dot 5 in all 3 of my cars, 2 of them have Wilwood front disc.. I haven't had any issues on the street.

 

[Pool Fixer]

I'm getting ready to pour the brand new DOT 5 fluid into my master cylinder of my 68 GTX and my Buddy down the street from me
who is a Hot Rodder just bought a Wilwood system for his steel bodied chopped something or other! Well, they say that using DOT 5
fluid will void their warranty! WTF? The car doesn't have ABS. They have a good scam going though, Wilwood XR Race Only brake
fluid, 16.9 fl. oz. $51.30 @ Summit Racing! Dry Boiling point of 645F. Polygycol-Ether based Non DOT4 fluid. Lotsa Hocus-Pocus!
So, I gotta ask why does Wilwood NOT want you to use DOT 5 in their stuff?

Most of our cars sit for long periods. Id put in whatever won’t absorb moisture or is otherwise the most resistant to contamination. I’m dubious as to how well any of these companies will honor their warranty anyway so thier “you’ll void the warranty“ threats mean very little to me.

Specifying only their own brand is bush league. We all their stuff is rebranded something.