[s-cars] Brake Light Indicator and Bomb?

[Joe Petersack]

My 1993 S4 with 125K miles has been having hydraulic problems.  A 
while ago my trusted mechanic replaced the bomb and the power 
steering pump and flushed the system.  All was well for about 1 week 
then the  light started coming on.  We have now been through 3 bombs 
(his warranty) and many flushes. He says that there is still a lot of 
crud in the system and possibly new power steering fluid is stirring 
it up.  Suggests replacing everything!
Is there a fool proof way to clean out the system?  If so, is there a 
written procedure?
Thanks a lot.
   Joe