Power steering leak '79 K20

[zac]

While working to fix multiple engine oil leaks, I noticed the power steering box is leaking around the shaft that comes in from the steering wheel. Has anybody put new seals in there before? Is it worth it or better to find a good or rebuilt one? The box seemed to work fine for all 75 miles I have put on this truck so far. The reason I noticed the leak was that it seemed like a weird place to have a transmission fluid leak. Yes, someone put ATF in the power steering system. It seemed to work, and I doubt it's a disaster, but what's your input? How would I go about purging the whole system if I wanted to use say, oh, power steering fluid? Thanks