Jim D. writes:
>Excuse a dumb question from an uneducated Georgia redneck, but why would
>more moisture be absorbed by leaving the cap unscrewed than through the
>vent hole? I know there would be a larger surface exposed to the damp
>atmosphere, but I've always wondered why moisture isn't absorbed through
>the little vent hole.
>Just curious,
***************************
Jim,
No dumb questions here.
The way I see it is that when the cap is on, you have only the air trapped
inside. The only time the volume changes is when the fluid level changes.
Even then the vent hole is very very small and has to wind it's way through
a maze like trap, compared to the area with no cap, so very little 'new'
air is introduced. Once the initial water (from aforementioned air) is
absorbed no or very little new is introduced. You do still absorb that
water and it is one of the reasons that it is recommended that you change
your fluid every two years or so. Some (actually most) brake systems even
go as far as to use a rubber diaphragm to seal the system (similar to the
clutch). Leaving the cap off (which is what I was refering to) however,
exposes the entire top to the atmosphere, allowing it to continue to absorb
moisture as it will, because there is always a fresh supply wafting by -
leaving it unscrewed allows it to fall of at the first real braking
opportunity <G>
Barry Schwartz in San Diego, CA
Bschwartz@encad.com
72-V6/5sp Spitfire ( daily driver )
70 GT6+ ( when I don't drive the Spitfire )
70 (sorta) Spitfire ( project )
73 Ford Courier ( parts hauler )
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