Perhaps I wasn't clear. There is nothing wrong with the zerk, grease purges from 3 of 4 seals, I pumped a lot thru. Its one trunnion that doesn't purge.
You just have caked up grease crud blocking grease from getting to that area.
Does it to our tractors and implements all the time.
Even greasing every time the equipment moves will
not prevent it.
Run it til it's hot and try again.
If that doest work, taking out the zert and using a small but stiff piece of safety wire and try to break up the crud will work.
Sometimes the heat and wire trick still won't work. High pressure grease guns won't either.
Then you just run it as is til replacement.