I just wanted to post this for the sake of saving someone some headache. My 1993 940 wagon began to exhibit the symptoms of "morning sickness" as the weather got colder. I thought the rack was going, which is strange at 179K miles. It was too cold to deal with it and I waited for an opportunity. However, one day the morning sickness turned into a permanent no PS and also the battery began to die in mid drive. I just barely made it to my driveway and coasted in. Next day was not so cold and I looked to find a harmonic balancer completely delaminated. The part attached tot he crank shaft was able to spin independently of the outer pulley part. I replaced the HB with an aftermarket Korean part (Pro Parts Sweden) and all the power steering issued were gone. The entire problem was in the harmonic balancer. So if anyone experiences stiff power steering in the morning and is thinking of replacing a rack or pump or fluid, first make sure your harmonic balancer is in good shape. the symptoms were very similar to "morning sickness", which usually suggests a bad rack or low fluid, etc.

--
Vladimir. '98 S70 base, 5-speed manual - his, '93 945 - hers