Fiat-hitachi EX120 Parts Catalog – What You Need on the Bench

I’ll tell you straight. Ordering the wrong part for an EX120 costs you more than just time. I’ve watched guys pull a valve plate off a shelf, only to find it’s the wrong revision – then they’re chasing a solenoid that doesn’t match. That happens when you rely on a third-party parts list that was copied from a photocopy. This Fiat-hitachi EX120 Parts Catalog is the OEM document. 142 pages. No reprints. No generic cross-references. It’s the same binder that Hitachi dealers used when Serial No. 15001 rolled off the line.

Pump Section: Piston and Regulator Breakdown

Every pump component is laid out by the factory. You get the piston group, the regulator cover, the valve cover, the control part, both rotary groups (drive and idler side), and the pilot gear pump. Each of those sub-sections has its own exploded diagram with part numbers and quantities. Need to order a new regulator cover? You flip to that page and see the exact bolt pattern. No guessing if the aftermarket regulator matches – you’ve got the Hitachi drawing.

Does This Catalog Cover the Brake Valve?

Yes. The MOTOR;OIL section lists the brake valves for both the swing and travel motors. You’ll find duplicate entries for VALVE; BRAKE under MOTOR; OIL (TRAVEL) and under VALVE. That’s not a typo – the EX120 uses a brake valve in both locations, and they are different part numbers. I’ve seen shade-tree rebuilds try to swap them. This catalog kills that mistake cold. Also included are relief valves for each motor: swing, travel, and the separate relief valves listed under MOTOR; OIL.

142 Pages of Factory Part Numbers

That page count is not padding. It covers the entire hydraulic system: pump, swing motor, travel motor, control valve stack, pilot valves, solenoid valves, check valves, shockless valves, lock valves, holding valves, and the full cylinder set (boom right, boom left, arm, bucket, clamshell). The PARTS INDEX at the back runs every number in sequence. You can go from a worn O-ring straight to the correct Hitachi part number without calling a dealer.

Valve Section: Control and Pilot Valves

The VALVE chapter is the thickest part of this catalog. Control valves are broken into five sub-sections (1/5 through 5/5). Pilot valves appear six times – each one covers a different hydraulic function. There’s also a solenoid valve section, check valve, shockless, lock valve, relief, and four holding valve entries. If you’re rebuilding a valve bank, you need the exact sub-section. The catalog’s numbering matches the machine’s serial range. Get the right page, get the right part. HITACHI EX120 Hydraulic Excavator Parts Catalog is the sibling service manual that pairs with this parts list.

Who Actually Needs This Parts Catalog?

Anyone who owns or services an EX120. That includes equipment owners who do their own rebuilds, independent hydraulic shops that take in excavator work, and dealers who need to verify supersessions. This is not a repair manual – it won’t tell you torque sequences. But without the OEM part numbers, you’re throwing darts in the dark. The FOREWORD (page 5) explains the compatibility codes: I, P, T, Y. Pay attention to those. They save you from ordering a part that has been superseded. HITACHI EX120 Parts Catalog is the same document if you need the separate listing.

Source Validity: OEM vs Aftermarket Reprints

This is an original Hitachi factory PDF. Not a scanned copy with blurred part numbers. Not a third-party compilation that mixes up the regulator cover with the valve cover. The OCR excerpt shows the actual table of contents in both Japanese and English. It even includes the service code letters (W, D, K, R, S, OP, OS, US, #). Those codes are stripped out of aftermarket versions. If you’ve ever tried to decode a reprint that left off the “R” for adjuster shims, you know exactly what I’m talking about. Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 Parts Catalog covers other machines in the family if your shop runs a fleet.

How to Use This Catalog on the Job

Pull the hydraulic component off the EX120. Clean it. Find the plate number or stamp. Open the PDF, search that number in the PARTS INDEX. It gives you the page. That page shows the exploded assembly. Order the exact Hitachi part – not a generic substitute. The FOREWORD also defines LEFT/RIGHT/FRONT/REAR for the machine (boom side is front, engine side is rear, driver’s seat is left). That orientation matters when you’re ordering a boom cylinder seal kit. Automotive Industry Overview might cover general hydraulic systems, but for the EX120, you want the factory spec. Automotive Industry Overview is a reference for fundamentals – this catalog is the real deal for that specific machine.

FAQ

Can I use this parts catalog to find torque specs for the EX120?

No. This document lists part numbers, not torque values. You need the service manual for assembly torques.

Does the catalog include part numbers for the brake valve if my machine has serial number after 15001?

The catalog covers from Serial No. 15001 upward, but includes compatibility codes for revisions. If the brake valve was changed later, the “I” or “T” code will point you to the superseded part number. Check the applicable serial number range printed in the section header. For machines after a certain build date, look for the “D” code (date change) or “H” (manufacturing number). The FOREWORD explains each code. If you are still uncertain, contact your dealer with the machine’s serial number – this catalog gives you the starting point to ask the right questions.

Stop chasing parts from blurry photocopies. Get the actual Hitachi factory document. 142 pages, numbered sections, OEM part numbers for every pump, motor, valve, and cylinder on the EX120. Download the Factory Manual and keep it on your tablet or print the sections you need. Your bench will thank you.