bdscott

I am getting ready to upgrade the brake fluid for track use. The manufacture's recommendation is to use a fluid with at least 534 degrees Fahrenheit dry boiling point. It also says to avoid silicone or DOT 5 brake fluids. Castrol SRF is a DOT 4 fluid but is a silicon ester type fluid. Is silicon ester considered a silicone? Is this permissible in the C7 Z06?

AzDave47

Check out this site info.

https://www.lelandwest.com/brake-flu...ow=1&SF=4&ST=2

bdscott

Thanks for the reference. Looks like he would say that Castrol SRF is not a silicone based brake fluid. I thought I had read elsewhere that it was--hence the confusion.

AzDave47

The Castrol SRF is not a silicone based fluid. It is generally considered the top fluid with a price to match.

The Wilwood looks like a very good value.

Bill Dearborn

Which manufacturer recommends a dry boiling point over 534 deg? Anything I see from GM just states DOT4 which is spec'd at more than 446 degrees. Most have less than a 500 deg dry boiling point.

I like the Wilwood fluid. Both the 570 and 600 Plus.

Bill

BEZ06

Many thousands of us have just flushed Castrol SRF into the brake systems of our Vettes with no problems.

As has been said, SRF is not a "silicone based" fluid, and as you mentioned it has "silicon (no "e" in the Castrol spelling) ester" in the blend. Here's some info from the Castrol site:
What the "base" of SRF is I dunno!? The base of most DOT 3, 4, and 5.1 fluids is glycol ether, and the DOT 4 and 5.1 fluids usually have borate esters added. Maybe SRF uses a base of glycol ether but adds silicon ester instead of borate ester - hoonose?

In that quote above from the Castrol site it does use the wording: "absorbs less water than conventional glycol ether fluids", and I suspect that it does use glycol ether as the base, but uses the silicon ester that makes it a "unique...technology".

Let me add that I believe some European fluids are designated 5.1, and also use the terminologies of DOT 4 Plus or Super DOT 4.

I believe our GM DOT 4 clutch fluid is a relabeled Pentosin product that they call a "Super DOT 4", but is just DOT 4 when sold here in the U.S.:

Take a look at this StopTech White Paper Tech Bulletin:

http://www.stoptech.com/technical-su...rs/brake-fluid


In there you can read that DOT 3 fluids apparently usually are a glycol ether base, but "not because they are required to be". Then DOT 4 and 5.1 fluids start to add borate esters to the mix, and maybe that's where Castrol uses the silicon ester instead.


Bottom line - you can just flush Castrol SRF into your C7 brake system just as you would if flushing in any other DOT 4 fluid.

.

Fmpcbrooks

Since I'm new to this, why do I need to remove dot 4 brake fluid after track day. I track 4-5 times during winter months in Fl.

BEZ06

DOT 4 is in my brake system year round.

.

AzDave47

You don't need to replace it.

Fmpcbrooks

I've wondered about this because corvette Manual said to take it out. Thanks guys.

Louis Gigliotti

The SRF is not very hygroscopic. Its wet boiling point is higher than some fluids dry boiling point. Im a big fan of the Endless fluid as well as the SRF.