Heads up... you need to take pressure off of the fitting by loosening/wrenching the coupler body on the gun tip. That's the gist. Hope it helps someone. Rant follows. No need to read it.... I'm just letting off steam. Good god. I'm in a bad enough mood over an obdurate repair tonight (it's my nature to attribute personalities to machines). This has happened often enough before but tonight I was just so pissed that I yanked the #ucking zerk right out of it's threads. Much swearing and throwing of tools ensued. So I google "stuck zerk" and find many pages of reference to this exact phenomena. For instance... http://www.tractorbynet.com/forums/kubota-owning-operating/195690-grease-gun-stuck-zerks.html Seems it's "common knowledge" that when a gun (any gun) gets stuck on a zerk (as happens with surprising frequency apparently) you need to loosen the coupler body with a wrench on the barrel of the gun to relieve pressure on the zerk. Only then can you remove the gun without breaking the damn fitting. I've been struggling with zerks since I can remember. Never learned since I only meet them about once every five years or so. I'd assumed I was missing some technique that involved twisting or something to get it off the zerk. So I discover it's not a technique after all. It's a matter of messing up a job enough times to discover a work-around that "everybody else knows already". How can such a common tool be designed for trouble like this?