IHI 55N Mini Excavator Parts Catalog (P/N PUB.No.2)

IHI publication PUB.No.2 is the parts catalog for the Model 55N mini excavator, serial WP000001 and up. Component illustrations are matched with part numbers, quantities, serial applicability, and interchangeability notes. This is a parts reference; step-by-step repair procedures are not included.

• Undercarriage and swing structure: Crawler shoe assemblies, front idlers, upper and lower rollers, and the turntable and swing bearing, with related mounting hardware.

• Hydraulic components: Illustrated breakdowns of traction and swing motors, rotary joints, control valves, oil pumps, and boom, arm, bucket, and blade cylinders.

• Piping and controls: Return and suction lines, pump discharge and boom swing piping, and control connections for standard, short-lever, A–D, and A–F configurations.

• Power unit: Engine and accessories, air cleaner and muffler, fuel tank and piping, and the oil pump drive device, with component identification lists.

• Cab and electrical equipment: Canopy and TOPS versions, operator seats, cab components, electrical harness arrangements, and instrument panel parts.

• Attachments and options: Hoe and blade attachments, standard and long-arm configurations, spare-port and power-port piping, and boom-holding equipment.

The catalog is suited to parts staff and mechanics who can match illustrated assemblies to the machine and interpret serial-number and interchangeability entries.

Serial Breaks and Replacement Parts

Control-lever assembly listings distinguish machines through WP000159 from WP000160 onward. A main relief valve in the control-valve assembly changes at WP000220, while short-lever remote-control valve listings change at WP000236. These distinctions help match replacement parts to the machine’s build before ordering.

Interchangeability symbols identify compatible and incompatible replacements. The Engine & Accessories sheet also specifies coordinated replacement of certain mounting brackets. Serial applicability reflects factory shipments; later field modifications require separate verification.

Hydraulic Assemblies and Attachment Parts

Traction Motor Ass’y and Swing Motor Ass’y exploded views identify reduction gears, bearings, and seal components. Control Valve Ass’y and Rotary Joint Ass’y section views locate internal parts by numbered callout.

Cylinder lists distinguish seal kits from piston rods, tubes, cylinder heads, cushion bearings, and individual sealing components. Boom cylinder entries identify cabin/TOPS versions, while attachment piping lists distinguish standard and long-arm arrangements.

The piping illustrations show hose and fitting relationships across the machine. Suspension-seat and short-lever configurations have separate entries, alongside the A–D and A–F control-change arrangements.

Always verify system depressurization and component integrity before attempting service.

Engine, Cab, and Electrical Coverage

The power-unit section identifies the Yanmar 4TNE94-EIK engine assembly and its external equipment. Radiator, oil cooler, air cleaner, muffler, fuel pump, and water separator parts are listed; internal engine overhaul instructions are outside this catalog’s scope.

Cab illustrations cover glazing, wipers, door hardware, seats, and canopy components. The cab-heater parts list is included, but its corresponding illustration is missing from this PDF.

Electric System and Instrument Panel Ass’y illustrations locate harnesses, battery connections, relays, switches, and fuses. Electrical circuit schematics and diagnostic test charts are not included.

Selected Bucket Sizes and Hardware

A few entries from the hoe-bucket parts list show how the catalog records component sizes. The standard bucket is listed at 685 mm wide, with other bucket versions listed at 485 mm, 585 mm, and 725 mm.

The side-cutter bolts are listed as M16 × 45 with a 1.5 mm thread pitch. These are component dimensions for parts identification, rather than tightening specifications or service limits.

PDF Navigation and Included Pages

Text search and drawing detail: The existing OCR supports partial text search, but some model codes and many part-number entries are not reliably searchable. Embedded bookmarks open the catalog sections and parts index. Small callouts in dense piping and valve drawings are clearer when enlarged.

The download contains one printable 321-page PDF, with English instructions and English/Japanese parts descriptions. The total includes 243 illustration and parts-list pages, 20 parts-index pages, five introductory pages, one cover, 14 section dividers, and 38 MEMO pages.