A while back I bought a new grease gun, looked neat and was on sale so I picked it up even though I have a few. Never could get the darn thing to work good, it had plenty of tension the first few strokes then not much resistance so not pumping too much grease. I kept doing what was suggested to try and get the air out but nothing seemed to work. Finally took it apart and in the grease I found a small broken o-ring that looked like it went on the air purge button plunger, plus the end of the plunger was misshaped. Not being one to throw anything away I did an experiment, took the purge unit out removed the spring and cut off the plunger and filled the button fitting with JB Weld. The air purge button is optional since you can purge the air by losening the barrel the old fashion way. Don't know why but I get a kick out of taking something broken and making it work.
