Grease cartridges take the often messy process of refilling a grease gun from a bulk grease supply, and simplify it to make it quick and easy. This is accomplished by using a pre-assembled and filled tube of grease that can be placed directly in the barrel of the gun. The cost of buying replacement cartridges can be a bit higher than buying grease in bulk, but the ease of use well compensates for this factor. Many different cartridges are available with different grease ratings for use in lubricating bearings, moving parts and gears.
Pull the spring-loaded rod handle out from the bottom of the gun until it locks into the open position.
Remove the head assembly of the grease gun by unscrewing it from the main body of the gun, and pull out the old grease canister with a pair of pliers.
Remove the bottom cap from the new grease cartridge. Insert the open end of the cartridge into the barrel of the grease gun. Pull the tab on the cap of the grease cartridge to open the top end, after it has been inserted into the barrel.
Loosely screw the head assembly back onto the barrel of the grease gun. Push the rod handle in to unlock it and force trapped air out of the barrel.
Tighten the head assembly completely, and depress the grease gun lever to bleed any remaining air out of the barrel and tubing. Repeatedly depress the lever until grease flows evenly from the grease gun.
Changing the cartridge of a grease gun can get messy, so work in an area that is easily cleaned. Bleed any pressure out of your grease gun before disassembling to replace the cartridge.