On a king pin job I once overlooked lining up the bushing's grease hole with the hole in the knuckle. wouldn't take grease. Rather than knock out the bushing I re drilled the hole using the knuckle as a guide. On rigs that haven't been greased in forever the bushings can twist out of line with the grease hole. Unlikely on a rig that has been regularly greased but I suppose it could happen. You might stick a cotter pin or wire in the hole to see if it goes in far enough. If not maybe the bushing has twisted.
