OK....I just replaced the calipers, rotors, drums, hardware, cylinders,
brake lines....everything but the master cylinder.

Here are the symptoms:

Little to no pedal at start up.
One pump and they are firm.
As long as rpm's are high there is plenty of pressure.
Left sitting idling for a bit and pressure is nil.
Have applied pressure to the system, push in clutch and can feel pressure
drop.

Troubleshot:  Readjusted rear brakes and rebled system

Suspect:  Master Cylinder

Question: Is there a vacuum assist to the brake system?  I have a loopy idle
also and need to crawl around and investigate a disconnected vacuum hose at
some point.  Could this also be the culprit?

Jason M. Yasment
'98 TDI
'84 Westfalia
Troy, NY