Zerk fittings are used to lubricate __________.

• A. Gears
• B. Single bearings
• C. Pulleys
• D. Sprockets

Answer: (B)

Zerk fittings are grease nipples used to inject lubricant into the lubrication path of rotating parts. The fitting’s purpose is to reach the bearing or bushing inside a component, where grease reduces friction and wear between the bearing surfaces as they rotate. They are not used to directly lubricate the surface of gears, or the teeth of pulleys and sprockets; those surfaces rely on other lubrication methods, while the bearing inside the pulley or sprocket is what’s serviced by the grease via the fitting. In practice, each bearing point typically has its own zerk fitting, so you grease single bearings individually.