On Wed, 16 Jul 2008, Stealth Pilot wrote:

On Tue, 15 Jul 2008 11:40:17 -0700, wrote:
What about using plain old DOT3 automotive brake fluid?

and being hydroscopic it entrains moisture which leads to corrosion on
the internal polished surfaces of the master cylinder.

That's easily handled by replacing the brake fluid every year or so.
Brake systems on cars routinely work for many years without any
maintenance at all. If the fluid is changed even every few years,
corrosion is a non-issue.

the correct red aviation brake fluid is cheaper as well.

LOL, in Oz maybe, but not here in the US. The last DOT 3 brake fluid I
bought was $0.99 per 12oz bottle.

the stuff I'm using is Royco 756 petroleum base hydraulic fluid. it is
milspec mil-h-5606.

hmm, flash point 105C / 221F, and burns about as good as diesel fuel. If
I were starting with a clean slate and looking for a fluid to fill a
hydraulic brake system, that would be second to last on the list, right
above gasoline. Of course most of us will never have a brake line fail
and spray fluid on a hot disk & caliper, but I'm more than willing to
change the seals in my brake system and change the fluid every year if
that's what it takes to drastically reduce the fire danger in case it does
happen.