This service repair manual covers the Clark NP 15, NP 20, and NP 12D forklift models. These robust machines are engineered for demanding industrial environments, providing reliable performance for a wide range of material handling tasks. Their design prioritizes efficiency and durability, making them essential tools for operations requiring consistent and powerful lifting capabilities. The intended use encompasses maintaining, assembling, disassembling, and servicing these forklifts to ensure optimal operation. This comprehensive manual is designed to be an indispensable resource for owners, technicians, and mechanics. It provides detailed guidance on maintaining and repairing the forklift, covering critical systems such as the frame, instruments and dash controls, transmission, electrical system, hydraulic system, tires, shielding, jacking and hoisting, and the mast system. With extensive information including specifications, diagrams, and numerous illustrations, this manual equips users with the knowledge necessary for effective troubleshooting and servicing.