Spent way too much time trying to replace a zerk and grease 4 little fittings on the Envoy. The zero itself was broke off inside a 90 degree adapter. I just drilled until a bunch of chunks came out so I could run a tap down the hole, somehow I managed to have a 1/4-28 on hand. Now for the fun part: getting grease into it. What a stubborn b!t©h! First problem was I couldn't get any as$ on the gun without the coupler blowing it around the fitting. It's my new Lincoln gun. The gun itself seems solid, but the coupler was a POS. At first I tried to tighten it a few times, but that did absolutely nothing. So I stole the fitting off of my old gun I should have thrown away and all of a sudden I could put some effort in. Still no go. At this point I'd had the fitting back out 3 times to verify it flowed and to see if even 1 drop of fresh red grease was in there. There wasn't, but I'd already scooped multiple gobs of it out from around the fitting itself. I was pretty fed up, but not ready to call it as the ball joint is pretty fresh and I want to keep it that way. So I decided to hit the joint with a propane torch and while I was letting the heat spread jumped on the Google machine. One of the suggestions was to turn the wheel full crank. I tried that and grease began to flow slowly, then normally. Thank God. I decided to send 30 pumps through that m'fer in case it decides it's gonna pull this crap again. Get it as squeaky clean as possible. I don't recall how much grease I was able to get in there when I initially did the things before their less than 2 year old boots were already torn, but since they were I went ahead and used it as a drain for the old stuff.