Flushing anti-freeze, 84 Audi 5000s

[asbury@northpole.med.uvm.edu (Jamie Asbury)]

Hello Audi owners,

I have an 84 Audi 5000s, non-quattro and want to flush my coolant 
system.  The haynes manual I have says to disconnect the input and
output of the water pump.  The problem is that those connections
seem to be quite fixed.  I can't see any threads or any way to 
disconnect them.  Almost like they are one time connections.  

Is there a suitable drain plug on the water pump, radiator or elsewhere
in the system?  Obviously, I'd like to make this as easy as possible.

Thanks for your responses!

Jamie