The piston is aluminum, not rubber.
Also I don't think metal contraction due to temp is relevant here.
The piston has a small rubber seal that I would bet is causing the problem.
Rubber gets hard when cold and doesn't seal that great.

-----Original Message-----
From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
Dave Mcneely
Sent: Tuesday, February 02, 2010 9:02 AM
To: vanagon@GERRY.VANAGON.COM
Subject: Re: No Clutch....

differential contraction of parts can allow fluid bypass more readily, I
think.  Though I have heard it suggested that if bypass is a sometime
problem, cold will make it less likely because the cylinder itself
contracts, while the piston is rubber and doesn't.  But I guess my ignorance
is showing.  David Mc

---- Dennis Haynes <d23haynes57@HOTMAIL.COM> wrote:
> Cold weather has a way of making clutch and brake hydraulics suddenly
fail.
> Especially if the fluid is old and has enough moisture in it to make ice
> crystals.
>
> Dennis
>
>
> -----Original Message-----
> From: Vanagon Mailing List [mailto:vanagon@gerry.vanagon.com] On Behalf Of
> Bill Shawley
> Sent: Monday, February 01, 2010 6:56 PM
> To: vanagon@GERRY.VANAGON.COM
> Subject: No Clutch....
>
> Ok gurus, went out to show the van some love, (and to measure something),
> took the key to start it as well.  Put my foot on the clutch and straight
to
> the floor, no resistance.  It is very cold, dark, and kind of immobilized
in
> some shoveled snow, hardcore diagnostics can wait.  No problems last time
I
> drove it, may 4-6 weeks ago.  Any guesses to trim the troubleshooting
curve
> for me?
>
>
>
> Ryan
>
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