A pneumatic tool that runs slowly or loses power may have worn rotor vanes. This replacement pack contains four vanes used inside the air motor of select grinders and ratchets. Each vane slides within the rotor while compressed air creates the force needed for rotation. Replacing the complete set helps maintain balanced contact inside the...Read more motor. Before ordering, verify the tool model and review its parts diagram. Shut off and disconnect the compressed-air supply, then release any stored pressure. Keep internal surfaces clean during service, check the cylinder for scratches, and place each vane in the direction shown by the manufacturer before reassembly.