Description

Fiat Hitachi KH125-3 Parts Catalog – Factory Specs for the Hydraulic Earth Drill

If you have ever tried to order a replacement part for a hydraulic earth drill without a factory parts breakdown, you know why I keep a copy of this on the bench. The Fiat Hitachi KH125-3 Parts Catalog is the only document I trust for part numbers on this machine. Aftermarket catalogs mix up suffixes or skip superseded numbers – that gets you a cylinder that doesn’t fit or a hose that’s three inches short. This catalog comes straight from Hitachi’s original print. 106 pages of exploded diagrams and part number lists, covering every subsystem from the main body piping to the optional buckets. If you turn a wrench on a KH125-3, this is your parts bible.

Let me walk you through what you actually get. The catalog is bilingual – Japanese and English – but the part numbers are the same in any language. Hitachi uses a standard P-prefix numbering system: P222-AL4-1 etc. You see that on page 1 of the PDF. Cross-reference that number against the exploded view for the assembly you’re working on, and you’re done. No guessing, no returns, no downtime because you ordered the wrong swivel joint.

Skip the aftermarket catalogs. They are wrong.

106 Pages: What You Actually Get in This Parts Catalog

Full breakdown of the Fiat Hitachi KH125-3 – not a generic hydraulic drill manual. The table of contents splits into three main sections: Main Body Piping (本体配管), Earth Drill Attachment (アースドリルアタッチメント), and Optional Parts (オプション部品). Each section then subdivides into exact component groups. For example, under Main Body Piping you get pilot piping, electrical parts, motor piping, cylinder piping, and covers. Under the Earth Drill Attachment you get front frame, thrust cylinder, lock cylinder, kelly device, upper buffer, swing device, retract cylinder, hoist rope assembly, rope, hook (4.9T), kelly bar, swivel joint, drum mirror, rope guide, indicator, stem rod, and miscellaneous attachments. Under Options you have the automatic soil removal device and buckets from 1580mm down to 880mm plus a chopping bucket. Every part number is listed next to its position in the diagram.

Which Sections Cover the Hydraulic Plumbing?

The two sections titled “Motor Piping” and “Cylinder Piping” inside both the Main Body Piping and Earth Drill Attachment sections are where you find all hose and tube part numbers. The motor piping group shows the hydraulic motor supply and return lines. The cylinder piping group covers the thrust cylinder, lock cylinder, and retract cylinder plumbing. If you are rebuilding the hydraulic circuit on this earth drill, you need those pages. Order everything at once rather than chasing individual lines later.

Get the Right Part Numbers the First Time

Match the exploded diagram to the part number list. Each diagram has callout numbers that link directly to a row in the parts table. The table gives you the part number, description, quantity required, and sometimes a remark about superseded numbers. Do not rely on the aftermarket cross-reference databases – I have seen them map a KH125-3 pilot valve to a crane valve that has a different port thread. Use the factory document. You will see things like “P222-AL4-1” for the main valve and corresponding breakdown. If you are rebuilding a bucket, the bucket sections list the wear plates and cutting edges individually.

Earth Drill Attachment: Breakdown by Component

This is where most of the wear parts live. The attachment section covers every welded assembly and bolted component on the drill string. Sections like “Front Frame” and “Kelly Device” show the structural parts. “Thrust Cylinder” and “Lock Cylinder” give you the rod seals and gland part numbers. The “Swivel Joint” section is important – that joint takes the full rotation torque, and if you order the wrong seal kit the joint leaks hydraulic oil down the kelly bar. The catalog lists the swivel joint as a complete assembly and also as individual parts. Check the “Swing Device” (フレーム起状装置) section if your drill frame tilt actuator is leaking.

Source Validity – OEM vs. Aftermarket Copies

This is a direct PDF from Hitachi’s original parts list publication. The file name itself – Hitachi_KH125-3_Parts_Catalog_en-ja-53914018094.pdf – tracks back to the factory. I have used Hitachi parts catalogs on crawler cranes for twenty years. The format is identical. Every page number and section header matches the bound paper manual I keep in the shop. Do not confuse this with a third-party compilation that renumbers parts to avoid copyright. Those copies get the torque sequence wrong – wait, this is a parts catalog, not a service manual, so torque specs aren’t here. But they get the part numbers wrong too, and that costs you real money when a cylinder arrives with the wrong port orientation.

For the hydraulic crawler crane version of this machine, see the HITACHI KH125-3 Hydraulic Crawler Crane Operation Manual. If you need the operator’s manual for the earth drill attachment, get the Hitachi KH125-3 Hydraulic Earth Drill Operator’s Manual. Also check the Fiat Hitachi ZW310, ZW310-A Parts Catalog – OEM Factory Specs for related wheel loader parts. For background on why OEM documentation matters in heavy equipment, read this Automotive Industry Overview and Automotive Industry Overview.

Is this manual in English?

Part numbers and descriptions are bilingual English and Japanese. The part number system is standard Hitachi.

Can I use this manual to find torque specs for the hydraulic fittings?

No – this is a parts catalog, not a service manual. It lists part numbers for ordering replacement components, but it does not give torque values, fluid capacities, or removal and installation procedures. For torque specs on fittings or cylinder gland nuts, you need the factory service manual for the KH125-3, which is sold separately. Do not guess torque on high-pressure hydraulic lines – a loose fitting can blow off at 3000 psi and cause serious injury. Get the correct manual for the job.

Every time I have needed a part for a KH125-3 earth drill, this catalog saved me from ordering the wrong item. The 106 pages cover the machine end to end, from the pilot lines in the cab to the chopping bucket teeth. If you work on these drills, you need this PDF on your tablet or printed in your shop. Access the Factory Manual now and stop guessing on part numbers.