[C320-list] Stuffing box nut replacement?

[Dave Hupe]

 Jeff- The packing  material is in the large packing nut, not in the "stuffing box".  You loosen the thin lock nut and then completely unthread the large nut and slide it toward the engine while still on the shaft.  You clean the old packing out of the inside of the large nut (using like dentist picks), clean up all the threads, insert new rings of packing (usually 3 rings) and then thread the large packing nut back on to compress the packing material against the forward end of the packing box and the shaft.  Then the lock nut gets tightened.  You don't crank the large nut down very tight to start.  You set it and run the engine/shaft for a while, then come back to snug it to the point where it drips only a little while motoring, but doesn't drip when sitting idle.
Pat -  This really sounds like a simple burr on a beginning thread (either the female threads of the nut or the male threads on the stuffing box end.  I would try cleaning the threads again, keep trying to get it started by hand,  and "persuade" it very carefully with a wrench.  >From what you have described, I really don't think you will need to do any of the other much more involved options. 
Dave Hupe
1994 C320 (#32)
Holland, MI