I have the same problem with the pump of my Audi V6.
I recognized that the PS fluid changes into foam after starting the engine.
The air bubbles seem to make the pump scream.
I remember cleaning the system with some chemicals. Perhaps some of these
stayed in the system after refilling it. I completely changed the fluid some
days ago, but I still get foam and the noise.
So how can I get chemicals or dirt out of the PS steering lines and how can
I get the air out???(Steering from left to right has no effect on the foam)

Raimund

-----Urspr�ngliche Nachricht-----
Von: Jeff Gilbert <Jeff_Gilbert/PeopleSoft@PEOPLESOFT.COM>
An: vanagon@GERRY.VANAGON.COM <vanagon@GERRY.VANAGON.COM>
Datum: Mittwoch, 10. Februar 1999 23:39
Betreff: power steering problems

>Hi,
>
>I have an 87 Westie Syncro that has been screaming something awful when
turning.
>This has been going on for quite awhile, but when I noticed that the pump
mount
>had cracked clean thru, I decided to fix the prob.  I got a used steering
pump
>and mount from a guy that was parting out his van, but after I put it in,
the
>van is screaming just as loud as before.  The noise is much louder when
turning
>the wheel at slow speeds.
>
>Could both pumps be shot?  Or could something else be the problem?  The
sound is
>positively comming from around the pump.  Any suggestions would be greatly
>appreciated.
>
>Thanks,
>
>Jeff
>