This document provides instructions for removing and installing cylinder heads on 345B and 345B L excavator models. The removal procedure involves removing various components to access the cylinder head such as the valve cover, rocker arms, and pushrods. Specific bolts and sensors must then be removed from the cylinder head. The installation procedure specifies cleaning surfaces, installing new gaskets and seals, and tightening head bolts to the proper torque. Special tools and repair kits are listed for tasks such as removing fuel filters and repairing damaged cylinder block threads.