How a Grease Gun Works

Grease guns are used to lubricate joints and connections that require re-greasing periodically. The grease gun is a portable device that stores a determined amount of grease. The grease is then pressurized, even slightly sometimes, to pump a concentrated amount of grease from an aperture located on the end of a small hose. The hose is flexible to allow maneuverability in situations where the grease fitting; also knows as a zerk fitting, is placed in a compromising position. Grease guns are found in every reputable repair shop. Most cars used to have multiple zerk fittings on the chassis components and drive shafts. Many newer import and domestic vehicles are now being manufactured with sealed chassis components that do not require greasing. However, once the components fail, the aftermarket replacement of the component most always is supplied with a zerk fitting.

Grease guns are hand-held. Most of the economic ones use a cartridge of grease inserted into the chamber of the gun. Installing the cartridge correctly will make less of a mess and ensure the grease purges out of the aperture correctly. The spring-loaded plunger on the bottom of this type of gun is pulled back and locked in an open position on a slot located at the bottom of the chamber. The top of the grease gun where the trigger and hose attachments are located is then unscrewed from the chamber of the gun. Removing the plastic cap of the cartridge will reveal the grease inside it. This is placed into the chamber grease side down. At the other end of the cartridge, now visible at the top of the chamber, is a flip top can lid. This is removed and discarded. The top of the gun is then screwed back onto the chamber tightly. A few hand pumps of the trigger or lever will prime any air pockets in the cartridge and a small amount of grease will purge from the aperture at the tip of the flexible hose. Each pump of the trigger will produce a small amount of grease.

What Grease Guns are Used For

Grease fittings or zerk fittings are located on many light to heavy duty trucks and SUVs. Some cars are still manufactured with grease fittings on the chassis components. Large commercial trucks have several zerk fittings located throughout the chassis, U-joints, drive shafts and other places that require lubrication. Lawn and garden tractors that use a pinion steering system may have tie rod ends and ball joints with zerk fittings requiring occasional grease. Mower decks for riding lawn mowers often have zerk fittings on the individual arbors of the deck. Industrial equipment for factories often have zerk fittings for machinery used requiring scheduled grease applications.