The document provides instructions for disassembling and assembling the main hydraulic pump of an M313D Wheeled Excavator. It describes 34 steps to disassemble the pump by removing components like bolts, seals, springs, pins, and housing pieces. It then describes 22 steps for reassembly, including installing seals, springs, and housing components in the reverse order and ensuring proper alignment and measurements using various tools. Precautions are outlined to contain fluids, mark parts positions, and be aware of spring forces during disassembly and assembly.