Description

Fiat-hitachi EX120-2 Parts Catalog

You’ve got an EX120-2 in the bay, a customer tapping his watch, and a part number that doesn’t match anything on the shelf. That’s the exact moment you realize a generic aftermarket parts list is garbage. Every line in the Fiat-hitachi EX120-2 Parts Catalog came from the same factory that built the machine. Not a third-party copy. Not a digital reprint of a reprint. 181 pages of OEM part numbers, exploded drawings, and compatibility marks that tell you exactly what fits and what doesn’t. If you’ve ever ordered a seal kit that was wrong by three millimeters, you know why this matters.

Validity of Source – OEM Print vs. Aftermarket Compilations

Aftermarket parts catalogs for the EX120-2 usually come from someone scanning a dog-eared paper manual and calling it good. I’ve seen “equivalent” numbers that list a part that was obsolete before the machine left the yard. This manual is the original Hitachi publication — document number PI2N-EI-5, issued for serial number 30001 and up. You get the same part numbering system the dealership uses. The foreword even explains how to read the LEFT/RIGHT/FRONT/REAR orientation using the driver’s seat as reference. That detail alone stops you from ordering the wrong hydraulic line. For a broader look at how factory documentation supports the Automotive Industry Overview of repair standards, but the real value here is the raw part data.

Technical Coverage – PUMP, MOTOR; OIL, VALVE, CYLINDER, ETC.

The table of contents splits into five main chapters: PUMP, MOTOR ; OIL, VALVE, CYLINDER, and ETC, followed by a PARTS INDEX. Each section opens with a group-level exploded diagram and a list of every subassembly down to the smallest O-ring. For the valve chapter, you’ll find the control valve body breakdown, individual spool and spring part numbers, and the service codes that tell you if a component can be replaced as a single part or requires the whole assembly. The cylinder section covers bucket, boom, and arm cylinders with piston seal, rod, and gland details — critical when you’re trying to stop internal leakage without buying a whole new ram. Every page is built around the same logic: part number, description, quantity per set, and compatibility codes (I, P, T, Y). No guesswork.

7 Systems Covered – Exactly the Sections You’ll Use

Seven distinct groups are covered in the PDF bookmarks. Beyond the major hydraulic systems, the ETC section picks up the miscellanea — pilot lines, fittings, decals, and hardware that don’t fit neatly into the other chapters. The Hitachi EX120-2 Excavator Parts Catalog page on this site gives you the full breakdown. If you work on other Fiat-hitachi models like the 850 series, check out the Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 Parts Catalog or the Fiat-hitachi ZX50U-2 Parts Catalog – 120 Pages of OEM Specs for similar quality.

Audience Fit – Who Needs This on the Workbench?

If you’re rebuilding the hydraulics on an EX120-2 — whether you own the machine or you’re running a shop that services construction equipment — this catalog is the difference between a one-call parts order and three trips to the supply house. The audience isn’t just “mechanics.” It’s the guy who has to explain to a customer why the replacement cylinder cost double because the kit didn’t include the backup rings. It’s the technician who questions every compatibility code and wants to know if a valve spool from an earlier serial range will interchange. The manual answers that with the 互換性 (Compatibility) column: I, P, T, Y marks. Pay attention to the footnote: if a part has an I-mark, you can only go one direction with the alternate — no backwards substitution. That kind of detail saves you from ordering a part that physically bolts up but kills the circuit pressure.

Using the Parts Catalog – Decoding the Codes

Flip to any page and you’ll see a column for 服務コード (Service Code). Symbols like W (field modification required), D (no single-part replacement — buy the assembly), K (part is in a service kit), R (quantity varies per machine), S (service-only part, not factory installed), OP (optional equipment), OS/US (oversize/undersize). The manual even tells you how to read the machine serial number range: the “H” prefix indicates the hydraulic component serial number stamped on the component plate, separate from the machine serial. That matters when a pump was swapped before you got the machine. You match the H-number, not the machine SN. Small details like that keep a rebuild on schedule.

FAQ

Does this catalog include torque specs or reassembly instructions?

No. This is a parts catalog, not a service manual. It gives you OEM part numbers, exploded views, quantities, and compatibility information. For torque values and disassembly steps, you need the separate service manual for the EX120-2.

How do I know if a part with an “OS” (oversize) mark will work on my machine?

The catalog lists oversize and undersize parts in the row immediately following the standard-size part. The machine serial number range at the top of the page tells you which machines received OS components from the factory. If your machine was originally built with standard-size cylinder bores, installing an OS piston without reaming the barrel will lock the assembly. The compatibility notes (particularly the “T” mark for combined interchange) show whether you can swap in a matched set of OS parts. Always verify the cylinder bore condition before ordering oversize seals — the catalog won’t stop you from making that mistake, but the data is there to avoid it.

Every service bay I’ve run has a stack of aftermarket catalogs that are wrong about at least one critical part number. This is the one you trust because it’s the one Hitachi printed. Access the Factory Manual now and keep it on the tablet next to your torque wrench.