Description

Hitachi Sumitomo 330-3, 330LC-3, 350H-3, 350LCH-3, 350LCK-3 Workshop Manual

I’ve pulled wrenches long enough to know what happens when you trust a third-party reprint for your Hitachi Sumitomo excavator. You torque a swing motor bolt to what some website calls “factory spec,” and it leaks hydraulic fluid all over your bay floor. Then you spend half a day tearing it back down because the gasket seat loaded wrong. That’s the cost of skipping the real document. This Hitachi Sumitomo 330-3, 330LC-3, 350H-3, 350LCH-3, 350LCK-3 Workshop Manual is the OEM print — 490 pages of factory-authorized procedures that Hitachi wrote for their own techs.

Why OEM Torque Specs Matter Here

Section 1 of this manual is called “Tightening Torque.” Not a generic chart copied from a 1998 textbook. It gives you the Torque chart for threaded fasteners, piping joints, and periodic replacement parts. The hydraulic system on these machines runs at pressures that will split a hose if the fitting is under-torqued by 10 ft-lb. I’ve seen it happen. Page 3 of the manual explains the page numbering system, but the real meat is in the torque table — you need that data to keep the pump device seated correctly when you reassemble it after a seal job. No aftermarket PDF I’ve seen gets these numbers right.

3 Major Sections You’ll Use Repeatedly

The manual is split into four sections. Section 2 covers the upperstructure — cab removal, counterweight install, pump device, control valve, swing device, pilot valve, and the 4-spool solenoid valve unit. Section 3 is the undercarriage: swing bearing, travel device, center joint, track adjuster, front idler, rollers, and track. Section 4 handles the front attachment and cylinders. Each subsection has a “Remove and Install” procedure followed by “Disassemble” and “Assemble” steps. You want to pull the main pump? The manual walks you through regulator disassembly, pilot pump tear-down, and main pump assembly with the exact clearances. No guessing.

Does This Manual Cover the Pump Device Disassembly?

Yes — and it’s detailed. Under Section 2, Pump Device, you get separate sub-procedures for disassembling the main pump, regulator, and pilot pump. The assembly instructions include the order of tightening bolts and the sequence for seating the regulator spool. If you’ve ever had a regulator stick because you skipped a lubrication step, you’ll appreciate the note about applying clean hydraulic oil to all sliding surfaces before assembly. The manual also includes a dedicated “Bleeding Air from Hydraulic Oil Tank” procedure — something most guys forget until the pump cavitates on startup.

Aftermarket Manuals vs. OEM: What’s Missing

Third-party manuals often cut out the safety pages and the painting specs. This OEM copy includes the Safety Alert Symbol explanations (page 4) and the painting precautions — which matter if you’re doing cab repairs and need to match the anti-corrosion coating. The signal control valve structure diagram in Section 2 is something I’ve never seen in a reprint. If you rely on a compiled PDF, you’re missing the factory’s own disassembly sequence for the control valve 4-spool side vs. 5-spool side. That’s not a small difference: misidentifying the spool layout can lead to cross-porting when you reassemble. Get the real document.

Bleeding Air from Hydraulic Oil Tank: Factory Procedure

Section 1 has a dedicated page called “Bleeding Air from Hydraulic Oil Tank.” It tells you to run the engine at low idle, cycle the attachments, and open the bleed port on top of the tank. The step includes a torque value for the bleed plug. Skip that, and you’ll have aerated oil that overheats your pump. The manual also covers periodic replacement parts under the torque section — hoses, O-rings, and seals that need swapping at specific hour intervals. That’s the kind of foresight that keeps a machine running 10,000 hours without a major incident.

What torque values does the manual include?

Section 1 has a full torque chart for bolts, piping joints, and periodic replacement parts. It covers both imperial and metric fasteners.

Does it cover the swing parking brake switch valve?

Yes. Section 2 includes the structure and maintenance standard for the swing parking brake switch valve.

Are the cylinder disassembly steps separate for mono boom and 2-piece boom?

Yes. Section 4 gives different procedures for mono boom and 2-piece boom attachments, including removal and installation of the positioning cylinder.

How does the manual handle the control valve — 4-spool vs. 5-spool?

There are two separate sub-sections under Control Valve: one for the 4-spool side and one for the 5-spool side. Each has its own disassembly and assembly steps, plus a housing disassembly guide. The 4-spool solenoid valve unit is covered in a separate section. If you don’t know which spool configuration your machine has, the manual tells you how to identify it based on the valve body markings. The assembly sequence for the 5-spool side requires torquing the spool cavity plugs in a specific order to avoid binding the valve. I’ve seen techs skip that and end up with a stuck spool that costs a grand to replace. Follow the manual.

You can pair this workshop manual with the related documentation: Hitachi Zaxis 330-3 350-3 Series Technical Manual covers operational principles and system activation, while Hitachi ZAXIS 330-3 350-3 Series Troubleshooting Manual gives diagnostic trees and performance tests. The Hitachi Sumitomo 330LC-3 350LC-3 Parts Catalog – 52 Pages helps with ordering the right seals and bearings. If you’re also working on a Manual Transmission vehicle, this manual won’t cover that — but for your Hitachi excavator, it’s the only source you need. Don’t trust a reprint when you can access the real thing. Manual Transmission specs don’t apply to hydraulic excavators; stick with the factory pages.

Access the Factory Manual and put it on your tablet in the shop. You’ll save yourself the headache of a second teardown.