Hitachi EX55UR Excavator Hydraulic Parts Catalog (P/N P1BG-E1-2)

This Hitachi EX55UR parts catalog, publication P1BG-E1-2, covers hydraulic equipment components for excavators with serial numbers 000101 and up. It provides exploded views and parts lists for identifying internal components and selecting replacement parts.

Text search and parts navigation: PDF text search is not available. Embedded bookmarks lead to the pump, motor, valve and cylinder sections and the numerical parts index.

• Pump assemblies: Exploded views and matching parts lists for the piston pump, including its gear pump assembly, cylinder set and seal kit.

• Swing and travel motors: Internal motor components, planetary gears, thrust plates and relief valves, with travel-motor breakdowns for the version without a parking brake.

• Control valves: Separate parts lists for assemblies with and without an attachment section, organized by machine serial range.

• Pilot and auxiliary valves: Component arrangements for pilot, solenoid, flow control and rotary valves, including their spools, springs, seals and associated hardware.

• Hydraulic cylinders: Boom, arm, bucket, offset and blade cylinder breakdowns, with tube and piston-rod assemblies, sealing components and individual seal-kit listings.

The catalog is suited to mechanics and parts staff who can identify hydraulic assemblies and use exploded views to match components before a repair.

Control and Pilot Valve Variants

The control-valve listings distinguish three machine serial ranges: 000101–000761, 000762–001988 and 001989 onwards. Each range has separate entries for valves with and without an attachment section, with their own inlet and spool-section parts lists.

Pilot valve 9134208 applies to serial numbers 000101–000358, while 4334029 applies from 000359 onwards. A separate pilot-valve assembly, 4330467, is listed from 000101 onwards.

Within the 4334029 assembly, pusher entries change at component manufacturing number H61367. The catalog distinguishes these H-prefixed component numbers from the excavator's machine serial number.

Pump, Motor and Relief-Valve Parts

The piston-pump listings distinguish the 4345903 cylinder set from the 4345905 seal kit. Kit-membership markings identify the seals included in the kit, helping you select the appropriate parts for a seal repair without confusing the kit with the cylinder set.

Swing-motor pages show the internal hydraulic components and planetary gear assembly. The travel-motor breakdown covers 4310049 without a parking brake; the 4339853 version with a parking brake is listed in the contents but has no corresponding exploded parts breakdown.

The separate listing for relief valve 4345830 identifies the housing, poppet, springs and shims. It supplies component identification, not pressure-setting specifications or a shim-adjustment procedure.

Cylinder Parts and Ordering Codes

Cylinder illustrations identify the relationship between tube assemblies, piston rods, heads, bushings, wipers and sealing components. Their matching tables list reference item numbers, part numbers and quantities.

Service code K marks parts included in a service kit; D identifies components that are not available individually. The foreword also explains ICA interchangeability codes, including one-way replacements and mutually interchangeable parts.

The numerical parts index connects a known part number to its printed page and item references. Assembly notes clarify when one assembly number covers components shown across several drawings.

Parts Identification and Repair Scope

This is a hydraulic component parts catalog, not a complete machine parts book or a service manual. It does not contain engine repair, electrical wiring diagrams, diagnostic tests or step-by-step overhaul procedures. The exploded views show component relationships without supplying the disassembly, inspection or adjustment instructions needed for an overhaul.

Because work on high-pressure hydraulics carries physical risks, repair work requires the relevant service and safety procedures in addition to parts identification.

Printable PDF and Included Pages

Supplied as one printable PDF in English and Japanese. The 164-page PDF includes 138 component drawing and parts-list pages, seven numerical parts-index pages and 19 supporting pages: two covers, one machine-record page, five foreword and catalog-instruction pages, two contents pages, one index divider, one Japanese contact-directory page and seven blank pages.