An impact wrench is a tool powered by compressed air or electricity. The high-torque action of the impact wrench can loosen bolts or nuts -- such as those on vehicle wheel studs -- that would normally be very difficult, if not impossible to remove by hand with a ratchet wrench. Electric impact wrenches usually have a sealed motor, but air impact wrenches have moving parts that must be lubricated periodically.
Disconnect the air hose from the wrench by pushing the collar fitting on the air hose away from the tool while pulling the air hose straight out of the tool.
Hold the tool with the air inlet -- usually located in the bottom of the hand grip -- facing upward.
Squeeze the trigger and hold it in.
Squeeze one or two drops of light motor oil into the air inlet hole.
Release the trigger. Wipe up any spilled oil from the exterior of the tool with a rag.
