The document provides instructions for removing, disassembling, assembling, and installing a piston motor (hydraulic fan) for Caterpillar 336D and 336D L excavators. The removal process involves detaching hoses and electrical connections, then lifting the fan motor assembly and piston motor. Disassembly requires using various tools to remove individual components like bearings, seals, springs and pistons. Reassembly follows the reverse order, noting requirements like heating/cooling parts and using tools to install retaining rings and seals. Installation connects all hoses and mounts the assembled fan motor assembly back in place.