A grease gun is used to inject grease under pressure through specialized fittings, called Zerk fittings, to lubricate bearings, gears and other moving parts. Grease guns can be powered manually via a lever or trigger pump or by air or hydraulics. Most accept standard grease cartridges, which may be filled with nearly any weight of grease from lightweight synthetic lubricants to heavy axle grease. Loading or replacing the cartridge consists of inserting a new cartridge, priming the gun and bleeding off trapped air.
Unscrew the head of the grease gun from the barrel by twisting it counterclockwise.
Pull out on the spring-loaded rod handle at the bottom of the gun and lock the notch in the rod into the detent at the base of the barrel.
Remove the old cartridge by pulling it out through the top of the barrel. If it's hard to remove, use pliers.
Remove the bottom end cap from the new cartridge and push the cartridge completely into the barrel, open end down. Use the pull tab to remove the top seal from the grease cartridge.
Screw the head onto the barrel loosely. Release the rod handle from the bottom of the barrel and push on it lightly to remove trapped air.
Finish tightening the grease gun head on the barrel. Press the bleeder valve on the head to release any remaining air.
Depress the lever repeatedly until the grease flows out of the hose or coupler, fitting smoothly.
