Volvo Repair: 87 240 wagon power steering, hands off the wheel, internal failures

Question
I have reasonable skills.  Car has over 200k, and I have three of
these now ('91, '93 Classic and the '87, had an '83).  Steering of
'87
is too light when power assist is working.  I have carefully
aligned it
several times and do not believe this is the problem as steers
great
when belt removed, also with belt in place but hands off the
wheel
the car tracks great without wandering.  Different tires
makes no difference, either.  My Dad thinks that on the power
steering centering(?) valve, the
spring that gives "feedback" is too weak; I think I have read
about a
nylon shim that can be installed.  Do you have any ideas about
this.  

Thanks!

Answer
Hello Stephan,
           Without being there to fully know what the steering feels like..my guess is a failed rack.I rarely get into disecting a rack assembly..time considerations.Almost always racks fail because the oil within is loaded with hundreds of thousands of miles of use and causes leaks and internal failures...I recommend that rack oil be chnged every 50,000.
        The effort to rebuilt a rack and the possibility of it failing again is too great.
         If you decide to put a new/rebuilt one in the 240 you may find one on the net for as little as 200usd...you'll probably have to return your failed one for rebuild...be sure it looks normal or they will reject it for a core...cost you at least 100usd.
              Hope I helped you,
                             Bilbo