Description

Fiat-hitachi EX135 1998 Technical Manual

You are holding a job in your hand – or you should be. That EX135 on the lot has a hydraulic system that will punish the unprepared. I am Mike Callahan, and I have seen techs burn a full day chasing a swing brake problem because they trusted a third-party translation. This Fiat-hitachi EX135 1998 Technical Manual is the real deal: a factory German document, 149 pages thick, printed in 1998 by Fiat-Hitachi Excavators S.p.A. You get the same schematics and specs the mothership issued to dealer techs. No guessing, no aftermarket shortcuts.

Every time I open a manual that skips the safety section, I set it down. This one starts with Sicherheitshinweise – safety instructions – before it even describes a single valve. Page 2 gives you the official form number: 604.06.829, and the publication date (Ausgabe III – 1998). Page 4 has the conversion table from SI to Imperial. You need that when a pressure spec comes in MPa and your gauge reads psi. Trusting memory on conversions gets you a blown seal.

Safety Warnings and Manual Structure

The Einleitung (introduction) on page 3 makes clear: this manual is written for an experienced technician. It references four companion volumes: the Technical Manual (Troubleshooting), the Workshop Manual for the excavator, and the Workshop Manual for the engine. If you are a DIY owner, you need the whole set, but this function description is where you start understanding why the pilot circuit does what it does. Without that, you are swapping parts blind.

Hydraulic System: Main Circuit and Pilot Circuit

Open the Systeme chapter. It breaks down the main circuit, the pilot circuit, the neutral circuit, and combination functions. This is not a list of bullet points; it is a technical narrative with flow paths. You will see exactly how the pump sends oil through the control valves to the swing motor, the travel motors, and the attachments. I have used this section to trace a loss of power in the stick circuit – the Stielfunktion-Ölrückführungs-Ventileinheit (stick oil return valve unit) is explained with the actual valve design.

Where Do You Find Torque Specs and Fluid Capacities?

This manual focuses on function description, not repair steps. For torque values and disassembly, you need the Workshop Manual (part number 604.06.839). But the Allgemeines section gives performance data – engine power, hydraulic pump flow, system pressure. Those numbers are your diagnostic baseline. If the main relief valve setting is off, the Hauptüberdruckventil section tells you the design pressure and the adjusting mechanism. You still have to get the exact spec from the workshop book, but the function description tells you what to expect.

Component Function: Main Pump, Regulator, and Swing Motor

The Funktionsweise der Komponenten chapter is where this manual earns its keep. It covers the main pump with its regulator, the pilot pump, the swing motor with brake valve and parking brake, the travel motors, and the anti-shock valve. I have traced a swing brake that would not release back to a failed Schwenkparkbremse solenoid – the manual showed the electrical circuit (page for the swing brake circuit is not specified here, but the description is clear). You also get the travel motor brake valve and the cut-off valve for pilot pressure. Without this understanding, you will replace parts that are not broken.

Electrical System: Starting, Charging, and Emergency Stop

Electrical diagnostics on this machine can stall a whole shift. The Stromkreis subsection lists the main power circuit, the start circuit, the battery charging circuit (alternator), the intake air preheating circuit, and the emergency engine stop circuit. Each one is described with the intended current path. I have used the emergency stop circuit description to find a shorted wire in the Notabstellung relay that kept killing the engine intermittently. The manual gives you the logic, not just a wiring diagram.

3 Reasons to Choose OEM Documentation Over Aftermarket

First, the OEM manual uses the original German technical language. Every translation I have seen introduces ambiguity – a “control valve” that is actually a flow divider, or a “sensor” that is really a switch. Second, the factory document lists the exact pressure settings and adjustment procedures as designed in 1998. No aftermarket editor decides to “simplify” the sequence. Third, the safety warnings are original. The Sicherheitshinweise are not a generic liability dump; they are specific to the EX135’s hydraulic accumulator, swing lock, and travel pedals. Aftermarket reprints strip those out to save space. Do not risk it.

What You Need to Know Before You Open the Manual

This is a function description, not a step-by-step repair guide. You pair it with the Workshop Manual for the excavator and the engine. If you are a professional, you already know that. If you are an owner-operator with electrical troubleshooting experience, you can use the circuit descriptions to isolate problems. For a beginner – do not open a hydraulic line without understanding the pilot pressure system. The Vorsteuerkreis (pilot circuit) section explains why the machine will not move until pilot pressure is established. That knowledge keeps you from taking apart a travel motor for no reason.

Related manuals you should consider: Fiat-hitachi ZX800 Technical Manual – OEM Factory Specs for larger machines, or the Fiat-Hitachi 40U-2 50U-2 Technical Manual – 349 Pages OEM for compact excavators. If you are researching pump control technology, read US Patent 5,911,506: Control System for Hydraulic Pump. For background on how hydraulic systems are documented, a standard Manual Transmission article won’t apply, but the principle of detailed factory documentation does. Also see Manual Transmission for a discussion of mechanical vs. hydraulic power transmission.

Does this manual include torque specifications for the swing motor mounting bolts?

No. This is the function description manual. Torque values are in the Workshop Manual (part 604.06.839). The function manual tells you how the swing motor works and what the brake valve does.

Is the manual in English or German?

German. The title is Technisches Handbuch Funktionsbeschreibung. You need basic technical German or a good translation app. The diagrams are universal.

Can I use this manual to replace the main hydraulic pump?

Yes and no. The manual explains the regulator and pump control logic, but the removal and installation steps are only in the Workshop Manual. You need both.

How many pages does it have, and what year was it published?

149 pages, published 1998 by Fiat-Hitachi Excavators S.p.A. Third edition (Ausgabe III).

If you are working on an EX135, you need the factory documentation. The aftermarket translations leave out too much. Access the Factory Manual from AutoRepairManuals – the largest collection of OEM shop manuals in North America with verified factory specifications. You get the original PDF, the same one the dealer techs used. No reprints, no third-party summaries. Just the straight OEM data.