Are the brake drums inside of the hub flange where the wheel bolts, or outside?  Is there a shoulder on the stud at the surface?  If drums are inside and there is a shoulder, you have to remove the hub by taking the bearings off the spindle, then remove a nut from the inside of the stud, which holds the drum to the hub.   If the drum is on the outside of the hub flange, you should be able to pull the drum off and then get to the studs, which are most likely just splined and hammered in from the back, like a pickup or car is, as the other guys have advised.

We don't have any outboard brakes on Budds, our Budds are all inboard and our outboards are all Accurides....Accurides don't break studs constantly like Budd's do, so I've not had the opportunity to replace any.