<VV> Effect of Steam in Brake Systems

[kovacsmj]

Joe,
Personally, I believe I remember enough about chemistry and physics to
know that when water boils it turns into oxygen and hydrogen. They are
gases. The gases expand, BUT, they are highly compressible, making your
break pedal very spongy. Perhaps enough to sink to the floor without
much effective breaking action.

 I do not believe you can create enough foot pressure to overcome this
problem. Also if the brake system (the brake cylinder) gets hot enough
to boil a few drops of water while under the hydraulic pressure I would
imagine you are going to experience brake fade as the hot shoes and
drums no longer create any effective friction rendering your brakes
virtually useless. I know this fade from high speed stops (legal)
without cooling the brakes off.

 Anybody else want to weigh in on this one??

PS: I use silicon fluid in most of my Vairs. The maint. book in my
Intrepid R/T recommends not to use silicon fluid.


Getting all the information is most of the solution.
 
MIKE KOVACS
 



Bill Elliot just advised that the formation of steam in a brake system
would
cause the pedal to drop to the floor. Personally (I don't think) I have
any
experience of a steamy brake system, although I'm sure I've put in a lot
of
miles with damp ones.
     It SEEMS to me that flash evaporation of water in a hot brake
system
would have the same effect as it does in a steam engine - it would
expand
forcefully and lock up the brake system (INCREASING rather than
DECREASING
the volume occupied by fluids in the close brake system).
     Can anyone elaborate on this process for me?

Joe Potts
Miami, Florida USA
1966 Corsa coupe 140hp 4-speed with A/C and DOT 5 brake fluid