My son took my 2002 Z06 to c of h and requested the mechanic change the brake fluid (routinte maintenance) and check it for racing, World Speedway, race driver training weekend course. They are a restoration shop and only stocked silicon dot 5.0 brake fluid, which they put in. So it has had silicon in it for 2 weeks. I have researched on the net and not it supposedly gunks with the residual dot 3 in the abs, gunks the abs and I presume could render the
abs and the active handling useless. This is not of concern to my son's racing, but is to me in my middle age driveing the z06. I have activated the abs and active handling on several occasions and consider it very these features helpful and lifesaving.

What should I do, I use the 06 a lot for daily driving which is a lot of fun.

Should I leave the silicon dot 5 fluid?
Empty each caliper's resoivor, blow out the system with air and flush and fill with dot 4 superblue?
Take it to the dealer and express mea culpa and ask them to replace the abs modulator and flush and replace fluid and empty calipers?
Give up, give the car to my son, buy another Z06
Take it back to c of h and ask for a dot 3 or dot 4 fill.

My son and I have different opinions (I will rule, my car, but want to do the engineering correct thing.) Please help. Research on the net is conflicting. Need some expert advice.

 

I did not chose to use DOT 5 fluid in my car for reasons such as you mention. I chose to use Motul RBF 600 as it is compatible with the stock fluid and could mix. It also has an extremely high wet and dry boiling point. However, recently I found out about Wilwood EXP 600 plus, which I intend to shift to (and is sold by forum vendor Hardbar).

If I were you, I would flush my fluid out with something like Motul or the Wilwood.

Here is a quote from the Wilwood site:

"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° F, and at 212° 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. DOT 5 fluid is best suited for show car applications where its anti-corrosion and paint friendly characteristics are important.

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’s Hi-Temp° 570 Racing Brake Fluid), flush the system completely, and flush it regularly, especially after severe temperatures have been experienced."

 

I use DOT 5 silicon all the time, road and track. The concern from GM is that it can boil if it gets too hot. Unless you are doing real competitive driving and I mean real big time racing two people I respect a great deal told me not to worry.

But I change it two - three times per year to make sure there are no issues.

 

Silicon fluid should not be used with ABS. (it's in the manual) it will form bubbles and doesn't work correctly. Great stuff in older vettes (85 & back) I'd get them to flush it and replace as soon as possible!
Dot 4 & 5 are not always Silicone.

 

Earnie
Just a slight correction to avoid people getting confused by your post.

Dot 4 is never silicon. It is compatible with Dot 3.

Dot 5 is always silicon. (Factory fill in Harley brake systems) Not compatible with anything else.

Dot 5.1 is not silicon. It is like regular brake fluid but with a higher boiling point. Don't know much about this. I think it was a pretty bad idea to include silicon in the Dot ratings cause it does cause confusion that could result in really screwing up one's brake system.

Original poster should flush system ASAP!

g

 

NO Dot 5 with ABS!

 

So, for a Z06 daily driver, what brand of brake fluid would you recommend?

 

Valvoline Synpower is one of the better (regular non race) another is ford

 

Motul or ATE Super Blue are great