'86/87 5KCSQT MC to Hydraulic assist seal?

["Swann, Benjamin R. (BSWANN)" <BSWANN@arinc.com>]

Is there an O-ring or other type of seal that can easily be replaced between
what is apparently a hydraulic Boost cylinder which the Brake Master
cylinder is mounted on?  

I discovered what apears to be a slow leak of Pentosin coming from where the
two mate together.  I noticed a line coming from the power steering
reserviour to a fitting connected to a cylinder that the Brake Master
Cylinder is mounted to.  Interesting engineering here!  Must be the AUDI
turbo answer to Vacuem assist - Correct? 

Is this an easy fix, or is  there possibly something more severe wrong?  Any
BTDT on this.  I hope this will not require compete replacement of rebuild
of this hydraulic cylinder (pre-master/boost cylinder) - whatever it is
called.

I'm losing about a drip every 2 minutes, or enough to draw the Pentosin
level down to min mark in about 2 days (causing the Brake warning light to
come on).  Bet others could trace some of their liquid gold leakage to this
rather than the steering rack.  Otherwise, Brake, steering systems work OK.

Ben Swann
'85 4KSQ
'86 5KCSQT
'87 5KCSQT Wagon