The gland must not be set up or packed so tightly that the stem binds.
Stuffing box gate valve.
Note whether the gland nose is.
The stuffing box bolts and nuts may have been tightened down unevenly during assembly.
Deep stuffing boxes are standard on gate and globe valves.
The valve box may be interfering with the operating key.
Inspect all of stem gate the valve should be all the way open to inspect the entire stem gate.
Loosen and retighten stuffing box bolts and nuts evenly.
Look down the valve box to see if it is to close to the operating nut.
If the stem of a globe valve is in good condition stuffing box leaks can usually be stopped by setting up on the gland.
Some factors to consider include.
The speaker mentioned that an ideal stuffing box contains 5 rings of packing and that deeper stuffing boxes are not preferred as only the two packing rings nearest the outside of the valve are fully compressed by the force from the packing follower.
If the leak persists a bent or scored valve stem may be the cause of the trouble.
Look for burrs or scaling.
If this does not stop the leakage repack the stuffing box.
The design provides extra packing for a more reliable stem seal or sufficient depth for packing with an optional lantern ring in the middle.