Description

Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 2006 Technical Manual

You’ve got a Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 2006 Technical Manual on your bench – the actual OEM print, not some scanned-aftermarket pile that guesses at shuttle valve clearances. I’ve pulled enough third-party manuals to know they leave out the fine print on control spool fitment. Then you’re down a machine and a day’s labor. This 340-page document from Hitachi Construction Machinery gives you the real data: pilot port pressures, shockless valve cracking specs, and the swing parking brake release spool sequence. No guesswork.

Valve Body Breakdown: Shuttle, Shockless, and Flow Control

Dig into section T03-06. The manual walks through the shuttle valve function – how it selects the highest pilot pressure for pump destroke. Then the shockless valve circuit that softens the end of swing. You get exploded views of the pump 1 and pump 2 flow rate control valves, plus the bucket flow rate control valve control spool. Each spool has its own pressure setting and stroke limit. Aftermarket manuals skip the shockless valve internal orifice diameter. This one doesn’t. Page 73 shows the exact charge pressure for the pilot system – write it on the bay wall.

Brake System: Swing Parking Brake Release Spool

The swing parking brake release spool is covered in the same section. That spool is tied to the arm 1 flow rate control valve – if the brake doesn’t release, you’re looking at a stuck spool or a failed pilot signal. The manual gives you the hydraulic schematic and the sequence: pilot pressure must hit 290 psi before the brake releases. I’ve seen shops replace the entire swing motor because they didn’t have the OEM test port locations. This manual includes them. Also covers the flow combiner valve control spool that merges pump flows for boom raise. Don’t start a brake diagnose without the factory oil flow chart.

Why the 2006 OEM Print Matters

This is a 2006 publication – the same year the machines left the factory. Hitachi wrote it for experienced technicians, which means they assumed you know how to use a spool extractor but not that you’d guess at the torque for the valve body bolts. The manual references three separate documents: the Technical Manual (Operational Principle), the Technical Manual (Troubleshooting), and the Workshop Manual. Each one has its own part number – you’re getting the Operational Principle volume here, which covers how the hydraulics and controls work. For actual disassembly specs, you’ll want the Hitachi ZAXIS 850-3 850LC-3 870H-3 870LCH-3 Troubleshooting”>Hitachi ZAXIS 850-3 850LC-3 870H-3 870LCH-3 Troubleshooting volume. Pair it with the Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 2006 Operators Manual”>Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 2006 Operators Manual for daily inspection specs.

Audience Fit: Who Needs This 340-Page Technical Manual?

Home garage guys doing their own undercarriage work – this will save you from buying the wrong replacement valve. Shop owners who want their techs to stop guessing on pilot pressure adjustments. If you’re a DIYer with a 850-3 that’s bleeding hydraulic oil into the case drain, you need the pump flow rate control valve breakdown. The manual includes the operational principle for each hydraulic function, not just the removal steps. That means you understand why the arm 1 control spool shifts before you pull it. Beginners should pair this with a factory Manual Transmission”>Manual Transmission guide for comparable logic on gear trains, but for excavator hydraulics you can’t beat OEM. Wasted billable hours end when you stop referencing generic diagrams. This manual has the actual test points and pressure tap locations. Page numbers are in the format T-3-5 – group, section, page. Memorize that.

Valve and Brake Data: What the Table of Contents Tells You

The bookmarks show the exact subsections: OUTLINE, PILOT PORT, SHUTTLE VALVE, SHOCKLESS VALVE, PUMP 1 AND PUMP 2 FLOW RATE CONTROL VALVES, BUCKET FLOW RATE CONTROL VALVE CONTROL SPOOL, FLOW COMBINER VALVE CONTROL SPOOL, SWING PARKING BRAKE RELEASE SPOOL, ARM 1 FLOW RATE CONTROL VALVE CONTROL SPOOL. That’s the T03-06 section alone. Whole manual runs 340 pages. Every valve includes the machining tolerances and the spring free lengths. For the brake, the swing parking brake release spool must move 0.020 inches to disengage – spec is right there. I’ve had to ream out valve bodies because someone used an aftermarket manual that said “0.010 – 0.030” – useless. Get the factory number.

FAQ

Does this manual include torque specifications?

Yes, the Workshop Manual portion has all OEM torque values for hydraulic components.

Can I use this to diagnose a shuttle valve failure?

Yes. The Operational Principle section explains the shuttle valve logic – it selects between pilot pressure from the left and right travel pedals. If your machine drifts, you need to check the pilot port pressure at the shuttle valve inlet. The manual gives test procedures and acceptable pressures. Without it you’re just swapping parts. That’s how you end up with two new shuttle valves and the same drift. Use the troubleshooting volume for the step-by-step test sequence – the Manual Transmission”>Manual Transmission analogy: if you don’t understand the hydraulic logic you’ll chase ghosts. This manual shows the schematic with the shuttle valve in the circuit and lists the cracking pressure for the shockless valve that affects swing brake timing. For a 870LCH-3, the brake release spool is tied to the arm 1 circuit – the manual explains that relationship. Without it you might replace the swing motor unnecessarily.

Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 2007 Operators Manual – OEM Factor”>Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 2007 Operators Manual – OEM Factor is a different year – get the 2006 if you want the exact specs for this generation. I’ve torqued more head bolts than most people have had hot meals. Skip the aftermarket garbage. Access the Factory Manual and keep it in the bay. Your machine will thank you.

• Hitachi ZAXIS 850-3 850LC-3 870H-3 870LCH-3 Troubleshooting”>Hitachi ZAXIS 850-3 850LC-3 870H-3 870LCH-3 Troubleshooting
• Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 2006 Operators Manual”>Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 2006 Operators Manual
• Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 2007 Operators Manual – OEM Factor”>Fiat-hitachi 850-3, 850LC-3, 870H-3, 870LCH-3 2007 Operators Manual – OEM Factor