Originally Posted by mkguitar
hmmm the HD dot 4 - I do not know if I would call that "dino".
a fluid which absorbs water is hygroscopic. this fluid can then freeze and the expanding ice can blow out seals in pistons and master cylinders.
all I know is dot 4 is dot 4
Dino meaning produced (refined) from naturally occuring crude oil. And Mike is correct about the definition of a hygroscopic fluid.
We are talking about a sealed system that is affected by condensation within the lines, reservoir, ect. That is very, very small trace amounts of moisture; certainly not enough to freeze and rupture your brake system, but enough to cause oxidation within the system.
Well, at least not cold enough in my part of Tennessee to rupture a brake system.
The point being that it is an very informative article and would encourage anyone to read it.