If I understand you correctly, the bolt that holds on the auxillary pulley, has oil leaking out ?
Odd as there is hole all the way through the aux shaft from what I can remember, I also seem to remember but could be wrong the aux bolt is a fine thread bolt(?) so should be a very snug fit with no real wobble at all once in say 5mm, if this is the case, checke it is the CORRECT thread, and just apply some sealant to the threads as you tighten it up again, or PLASTISCINE, works just as well.
tabetha