Power Steering Anatomy
 

I am looking at a power steering service, specifically the hoses. I see from a parts website there are 3 hoses, a high pressure, a return, and a suction hose.

Can someone give a breakdown of the 2002 A6 power steering anatomy and function?

Did you consider purchasing a repair manual?

Hoses leak, pumps whine/squeal. The rack gets heavy when seals start to go and fluid will eventually push out of the boots. Sounds like your pump from your description. I have had several of these cars (B5,C5) and they all have had a small amounts of pump noise, louder when cold. If I had a continuous whine my first instinct would be to check/replace the fluid and hope it cures it. Failing that, only a pump replacement would make the noise go away.

The power steering fluid should definitely be checked before purchasing parts. Yesterday I posted about my sisters A4 that had a horribly sounding power steering pump. The car has 80,000 miles and the pump had been replaced 3 times already. Procare told us to replace the reservoir, and when we were doing this we noticed some bubbles in the fluid. To fix this, we jacked the front of the car up and steered fully to the left and right while running the engine, periodically checking for bubles in the resevoir. After about 40 full turns the bubbles were gone and so was the whining.