We get lots of questions on how to clear air locks from grease guns, get them primed, keep them primed, and generally what goes on inside the sealed metal universe of a grease dispenser. We have a few simple tips to clear the airlock from any grease gun and keep it primed.
Priming a new grease gun
When you buy a new grease gun, there's no grease in the hose, so you'll need to prime it to clear out all that air. The problem is that without grease already in the head of the grease gun, the piston is pumping air and you may need to help push the grease up and out of the cartridge to get things moving.
3 easy tricks to clear air locks
1) When you screw on the barrel after loading a new tube of grease, back it off a full turn to allow a little air to seep out. This gives the air bubble above the grease a place to go.
2) If loosening the barrel doesn't work, try using the air bleeder valve if your gun has one. Keep pumping.
3) If you still can't get the gun primed, try to apply some manual pressure. Pull the t-pull so the follower rod comes back out of the barrel. While pulling straight down, twist it 1/4-1/2 turn. You'll feel it pop down and lock in place. you can now push up on the t-pull and it will be applying pressure to the follower plate and pushing the grease up. Leave your bleeder valve partially unscrewed, or pushed down if it's a button style, during this process.
By forcing the air out, you'll push grease into the chamber and allow the piston to do its job of pushing grease down the hose.
Keeping a grease gun primed forever
A common mistake is to pump grease until the cartridge is completely empty. This means that your hose is once again full of air and will need to primed again. The trick is to pump until you are almost out of grease, but there is still some in the hose and head of the gun. To check the amount of grease remaining, just pull down on the follower rod. It will stop when it hits the follower plate at the bottom of the grease, and show you how much you have left.