Hey guys

Car is an 02/03 a6 v6 tdi quattro, Its had a new genuine PAS pump, new fluid (correct mineral type ) and it still whines. I know some of the vag ranges suffer similar problems when the free-wheeling alternator pulley seizes up, but this car has the solid type pulley.
Ive tried roadtesting it to bleed the system, but still no joy, the fluid is still frothing up indicating air. New seals were also fitted to the unions, aside from the pump i cant see it being a rack, can anyone shed any light on it? Thanks in advance !!