Thanks for your input, everyone.

I've checked all braking and clutch components for leaks - none present.  I've put a quart of brake fluid into the system over 5 days of driving.

Based on the feedback the only possibility is a brake booster leak.  I'll go ahead and order one before driving any more.  
 
Chris S. 
'84 Westy -> http://www.knology.net/~vw/vws/hershey/
'01 NB TDI -> http://www.knology.net/~vw/Beetle.jpg
 
1-888-VW-PARTS <- Recommended Expert Vanagon Part Source

----- Original Message ----
From: neil N <musomuso@GMAIL.COM>
To: vanagon@GERRY.VANAGON.COM
Sent: Saturday, October 27, 2007 9:56:04 PM
Subject: Re: Case of the disappearing brake fluid

If you checked all brake hydraulic components (i.e. did you pull the
drums and check for fluid inside the rubber boots on wheel cylinders?
Flex hoses? Hard hydraulic lines?) then check at the base of the MC
for signs of fluid there. If fluid present, it could be leaky seals
between reservoir and MC or where hydraulic lines connect, or MC
itself.

If you remove the two nuts holding the MC to booster, you may be able
to pull it back a little (don't force it) and feel around if fluid
present on other side of MC (inside booster).

Did you check the clutch hydraulics? They share the same fluid. Also
there is a flex hose (NON hydraulic) between reservoir and clutch MC.

Cheers,

Neil.

--
Neil Nicholson. 1981 Air Cooled Westfalia -
"Jaco"  (Bustorius)

http://web.mac.com/tubaneil

On 10/27/07, Chris S. <mrpolak@yahoo.com> wrote:
> Alrighty folks.. my master cylinder keeps going low but I see no
 signs of leaks anywhere.  Is leaking into the brake booster?  The brakes
 seem fine otherwise.
>
> Thanks,
>
> Chris S.

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