Volvo Repair: 1997 Volvo 850 ball joint, wheel bearings, ball joints

Question
Hi there.  I have a '97 Volvo 850 that has erratic steering and tends to "wander" to the left and right.  I've been told the right ball joint needs replacing and therefore the whole control arm needs to be replaced.  Is this true?  Also, is fixing this likley to remedy the problem?
Thnaks for your help!

Answer
  Hi,
       Ball joints can cause front end problems...so can tie rod ends..wheel bearings..improper tire pressure..
     The rack/pinion steering assy do fail...
        Go to your favorite parts store...ask to see a ball joint for your car...you'll understand your options when you see the new part...I have not replaced a ball joint in a 850.

               Good luck,

                           Bilbo