Description

Fiat-hitachi EX120-5, EX120SS-5, EX120-5HG, EX120-5LV, EX120-5X Parts Catalog

I’ve been turning wrenches for 28 years, and nothing burns my tail faster than a parts counter guy handing me the wrong seal because the aftermarket catalog had the wrong number. This Fiat-hitachi EX120-5, EX120SS-5, EX120-5HG, EX120-5LV, EX120-5X Parts Catalog is the real deal – 275 pages of factory part numbers straight from Hitachi. You don’t “guess” what fits an EX120-5HG cylinder or which pump seal goes on an EX120SS-5. You look it up in the original document. Period.

Look, every part number in this book came off the line with the machine. The foreword spells out exactly how to order: model name, product identification number (that serial plate on the right side of the cab), part number, part name, quantity. The Japanese text is dense, but the numbers and diagrams cross borders. If you’ve got a Automotive Industry Overview, you already know that OEM data beats third-party reprints. This is the real thing.

That’s the difference between a job that stays together and a comeback.

Pump Assembly Breakdown and Part Numbers

The PUMP section is where you start when the hydraulics are weak or the pump is making noise. Each component is drawn with a reference number; the table below it gives the part number, name, quantity per machine, service code (W for field-fit, D for assembly-only, K for kit), and the serial number range that part fits. You get “OS” for oversize pistons and “US” for undersize. No guesswork. If you need to order a main pump for an EX120-5LV, the exact code is in this section. Don’t trust an aftermarket “cross-reference” that hasn’t seen a dyno. Use this.

5 Sections That Save You Time

The table of contents is short and brutal: PUMP, MOTOR ; OIL, VALVE, CYLINDER, PARTS INDEX. That’s it. Every hydraulic component on these machines falls into one of those folders. Inside each, the diagrams are exploded views – the same ones Hitachi service techs used when rebuilding a valve stack or resealing a cylinder. The PARTS INDEX at the back lists every part number in ascending order. Find the number, flip to the page, see the drawing. You can go from a broken machine to a correct pump packing kit in under five minutes.

Motor and Oil System: Component Identification

The MOTOR ; OIL section covers the travel motors, swing motor, and the oil cooler/ filter system. If your EX120-5HG has a drive motor leak, you’ll find the shaft seal part number, the O-ring sizes, and the exact quantity per motor. The service codes tell you if you need a kit (K) or if the part only comes as an assembly (D). One wrong O-ring can dump 10 gallons of hydraulic oil on the ground – and then you’re down for a day. This manual keeps you from making that mistake.

Valve Group: Factory Part Listings

Valve bodies get complicated fast. The main control valve, relief valves, and solenoid valves – each one has its own exploded diagram in the VALVE chapter. You’ll see the spool, spring, plug, and every washer with a Hitachi part number. I’ve seen guys try to rebuild a valve with generic O-rings. Don’t. The material and durometer are specified by the factory. The EX120-5X uses different relief settings than the EX120SS-5, and the parts mirror that. Use this catalog to get the right relief valve cartridge.

Cylinder Assembly: Seal Kits and Rebuild Parts

Cylinders live a hard life. The CYLINDER section covers boom, arm, bucket, and any auxiliary cylinders. Each cylinder is broken down to the rod seal, piston seal, wiper, and cushion rings. The part numbers for a seal kit on the EX120-5LV are listed with the exact quantities. Note the “R” service code – that means the quantity varies by serial number, so check your machine’s ID. Ordering wrong cylinder parts can bend a rod or blow a seal under load. That’s a safety issue, not just a repair delay.

For related documentation, check the HITACHI EX120-5 EX130H-5 Parts Catalog for the EX130H-5 variants, or the Fiat-hitachi EX120-5 EX130H-5 EX100-5 EX100M-5 1997 Operators Manual if you need operating procedures. There’s also the Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 Parts Catalog for larger tracks.

Why This Over an Aftermarket PDF?

Aftermarket parts catalogs often copy the same diagrams but scrub the part numbers or mix up revisions. This is the factory Scan of the original Hitachi publication – every page matches the paper manual from the 1990s. The Japanese text includes “まえがき” (foreword) that explains the “I”, “P”, “T”, “Y” compatibility codes between old and new parts. You can see if a newer superseeded part fits your machine. Aftermarket sources don’t include that. They don’t have the OS/US oversize and undersize listings either. If you’re rebuilding a pump on an EX120-5 with high hours, you need to know if a .010” oversize piston is available. It is, in this catalog.

And don’t forget safety. The service codes tell you when a part requires field modification (W) – that’s not “grind to fit”, that’s “call Hitachi for guidance”. Ignoring that can crack a valve housing. Automotive Industry Overview covers the standards behind these safety protocols. You owe it to yourself and anyone near the machine to use the real data.

Does this parts catalog cover the EX120-5E and EX120-5Z models as well?

Yes. The foreword lists EX120-5E and EX120-5Z along with the other models. The same sections apply.

Is the manual in English?

No. The text is Japanese. Part numbers, diagrams, and tables use universal numeric and symbol codes. If you can read a parts diagram, you can use it. The service codes (W,D,K,R,S,OP) are explained in Japanese but the symbols are standard. We recommend having a translation app for the foreword if you need the detailed compatibility rules.

Can I use this to order parts for an EX130H-5?

Yes, the catalog includes the EX130H-5 and EX130K-5. The pump and motor sections cover those models.

How do I find the part number for a valve spool?

Turn to the VALVE chapter. Locate your valve assembly by the exploded diagram. Each part has a reference number. Match it to the table. Spool part numbers are listed with the spring and plug. Use the Parts Index if you have a known number to cross-check the page.

Access the Factory Manual, put it on your laptop in the shop, and stop ordering parts by memory. The EX120-5 series has been around long enough that aftermarket “cross-references” are full of errors. This 275-page catalog is the only source that matches the iron. Get it, use it, and make your next rebuild go together with the right parts – the first time.