Hydraulic Pump Question

[Marc Boucher]

The hydraulic pump on my 1990 Audi 100 has developed a worsening leak.  It went from requiring topping up occasionally to its current state where it will go from the max to the min within 200 miles.

There does not appear to be any leak in any of the hoses, the reservoir, or the steering rack.  The leak appears to be isolated to one point in the pump:  A ring of metal about the size of a quarter that sits on the outside of the pump.  There are bubbles of the green hydraulic fluid coming from the space between the metal ring and the body of the pump.  

There are at least 2-3 of those metal rings.  They have groves perpendicular to each other almost as though they could be pulled or tightened by a large Phillips screwdriver.

Are there any simple options for fixing this, or does it generally require replacement of the pump.

Thanks,

MC