How To Use a Grease Gun

What are grease nipples?

Grease nipples are small but very important fittings used in automotive and other mechanical systems to enable lubricant to be fed into the system. As the name suggests, the lubricant is usually grease.

GREASE NIPPLES

Grease nipples contain a sprung ball bearing inside the nipple body. When a grease gun is connected to the grease nipple and pressure applied, the bearing compresses to allow the lubricant to flow into the joint.

How do you load a grease gun?

All grease guns accept purpose-made grease cartridges, of which there are many different types available. Ideally, you should check the manufacturer instructions if they are available, but most grease guns work in the following way.

Unscrew the head from the body of the grease gun and pull back the piston. Remove the large-cap from one end of the grease cartridge. For first time use, grease the outer edge and the inside of the cartridge to help the plunger locate. Insert the grease cartridge into the gun, with the end that had the cap on facing downwards. Tear off the seal from the outward-facing end of the cartridge. Re-assemble the head and release the plunger. Pump the handle to release the grease, bleeding out any excess air if necessary.

If you prefer not to use cartridges, you can also use a bulk grease container to fill the gun either by suction or manually. Beware – this is messy if you don’t use the suction method.

Applying the grease

Push the end of the nozzle over the grease nipple and pump the trigger or lever. The ball inside the grease nipple will compress under the pressure to allow grease to flow. Watch the fitting that you are greasing carefully, as grease will appear as soon as the joint is fully lubricated. You can sometimes actually hear a hiss before you see the grease appear.

If for any reason grease does not flow from the gun there is probably an airlock inside. You can release this by using the bleed valve (if one is fitted). If there is no bleed valve you should release the piston, unscrew the head by one turn and gradually push the piston forward to release the air. Re-tighten the head and try it again.

Releasing the gun from the grease nipple

Most grease guns “grab” the grease nipple to ensure that the grease is delivered correctly into the joint. To remove the nozzle from the grease nipple, the common method is to pull back firmly whilst rotating the nozzle gently from side to side.