Grease guns find many uses around the home and on the farm. Almost all mechanical equipment with rotating machinery requires grease periodically. Manual grease guns are available that are both cartridge and bulk-filled. Occasionally, a freshly charged grease gun fails to pump grease adequately, or pumps grease for a short time and abruptly stops. Trapped air within the gun often causes this symptom. Air pockets prevent a grease gun from dispensing grease. Air is commonly trapped inside the cartridge as a result of refilling the gun with grease, or installing a new cartridge. Removing the trapped air is necessary for the grease gun to operate properly.

Things You Will Need

Fresh tube of grease

Step 1

Ensure all fittings and caps are tight on the gun that might allow air to enter the barrel while pulling the follower rod out a second time.

Step 2

Pull the follower rod all the way out. The follower rod is the T-handle shaped rod at the bottom of the grease gun. The follower will lock in place when fully extended.

Step 3

Depress the air bleed valve at the grease gun head and push the follower rod back into the gun. Repeat this process 2 to 3 times to expel all of the air out of the grease gun. If the air gun is not equipped with an air bleed valve, unscrew the head of the gun one full turn. This will allow any air in the gun to vent out through the head while the follower rod presses into the gun.

Step 4

Retighten the head, or release the air bleed valve, once the bleeding process is complete. Wipe any excess grease from the head of the gun as well as the grease coupling.

Step 5

Pump the grease gun handle to start the grease flowing from the coupling. If fresh grease does not flow readily, repeat the air bleed procedure.
A grease gun refusing to pump grease is similar to a pump after losing its prime. Work the air out of the grease for the gun to pump properly. Try a newer cartridge of grease if the gun fails to vent all the air. Air pockets, or bubbles, in the grease itself may continue to burp through the hose and gun, preventing a steady flow of grease. Don't give up too soon, more than one grease gun getstossed into the scrap metal bin due only to trapped air.

Tips & Warnings

Load the grease gun with fresh, soft, grease to help eliminate air pockets.

#2 NLGI grease performs best in a cartridge-style grease gun.