Thanks, and a climate control question

[steveb@cme.nist.gov]

First, thanks for everyone's helpful responses regarding fixing my
old '85 Audi 5000S.  I'm going to tackle the whole project myself
although I'm still a little daunted at debugging that hydraulic system.
(Question: if I replace just the rack for now to get through inspection,
do I risk damaging it if any other component in the system is bad?  Are
there diagnostic procedures for determining if the pump or the accumulator
or the brake servo are bad, beyond visual external leak checks?)

I finally found a Haynes manual.  Would have preferred the Bentley
manual, but at $140 that would be a significant part of the repair cost.
Ah well.

Anyway, the last question for now: the automatic climate system seems
to have lost control of the air vents; it's always blowing out the
defrost vents, although everything else appears to work normally.
(fan speed, temp control, etc.)  This was mentioned in the archives
as a common problem (failed vaccuum solenoids?)  Anyone have pointers
for fixing it?  Part numbers?  (Since I'm about to order a ton of parts
anyway...)

Thanks again, you've been very helpful.
Steve