1997–2005 Fiat-Hitachi / Fiat-Kobelco FD 255 Crawler Dozer Operation and Maintenance Manual (P/N 604.00.761, 604.02.214)

• Covers the Fiat-Hitachi FD 255 crawler dozer, Series FD 255 / technical type 623.920.00.3, with the IVECO 8465.41.00.6 engine. Configuration data covers the HSU bulldozer, hydraulic angledozer, optional PD20 three-shank ripper, ROPS canopy, and enclosed safety cab.
• The 465-page PDF combines the Fiat-Hitachi Operation and Maintenance Instruction Manual, Print No. 604.00.761, with the FD255 Service Manual, Print No. 604.02.214.
• The maintenance schedule contains 41 numbered operations, from 10-hour track-frame support lubrication through 3000-hour air-conditioner filter replacement, plus variable services for track tension, idlers and rollers, and fuel-system bleeding.
• Repair coverage includes the engine, torque converter, three-forward/three-reverse powershift transmission, central bevel reduction, wet steering clutches, oil-bath band brakes, final drives, undercarriage, dozer hydraulic system, and electrical equipment.
• Factory test data includes injection timing and pressure, transmission and steering control pressures, brake-valve settings, hydraulic pump flow, relief-valve pressures, cylinder drift limits, operating speeds, wear limits, fits, and tightening torques.
• Specialist tool references include cylinder-liner protrusion tool P/N 75298636, injection-pump plunger-lift tool P/N 75295905, transmission clutch-spring tool P/N 75297418, and bevel-gear backlash tool P/N 75295253.
• Electrical and visual coverage includes the 24 V system, twin 12 V batteries, the electronically regulated alternator, fuse assignments, safety-decal location charts, component-location views, full wiring diagrams, and troubleshooting charts. Named visuals include the Position of Center of Gravity drawing, Controls and Instruments / Instrument Panel views, the Transmission Hydraulic Converter Diagram, the Steering Clutches and Brakes Hydraulic System schematic, and Checking and Adjusting Cylinder Sleeve Protrusion illustrations.

Operation, Configuration, and Scheduled Service

The operating section identifies the blade, steering clutch/brake, transmission, throttle, ripper, safety-lock, and cab controls before covering engine start-up, warm-up, machine movement, shutdown, and daily level checks. The Electronic Data Monitor is explained indicator by indicator, including low transmission pressure, engine and transmission oil temperature, coolant level, battery charging, filter restriction, fuel level, and general fault warnings. Separate views show the ROPS and cab instrument arrangements rather than treating every FD 255 as one configuration.

Field-operation guidance covers dozing, slot dozing, side cuts, leveling, road and ditch work, ramp formation, pushing and pulling, boulder handling, ravines, steep slopes, frozen ground, and ripper use. It also documents cab tilting with the hand pump, lowering the equipment when the engine is inoperative, transport, towing after manual brake release, cold-weather preparation, and long-term storage. Raised equipment must be mechanically supported before repair work, hydraulic pressure relieved before lines are opened, and the batteries isolated before electrical service.

Capacity tables identify 65 L for the cooling system, 22 L for engine oil, 67 L for the converter/transmission group, 130 L for the equipment hydraulic system, and 82 L for each final drive. The operation table lists the fuel tank at 495 L, while the service technical-data table gives a 500 L first-fill quantity. Lubricant grades and ambient-temperature ranges are provided for the engine, powertrain, steering-clutch/brake housing, final drives, rollers, and cab-tilting pump.

Repair Coverage, Tests, and Shop Data

The service manual moves from fault diagnosis into removal, teardown, inspection, repair, assembly, installation, adjustment, and testing. Engine procedures cover cylinder liners, crankshaft and camshaft, pistons and connecting rods, timing gears, cylinder head and valves, injector sleeves, lubrication and cooling pumps, turbocharger, injectors, and the fuel-injection pump and governor. Powertrain chapters cover converter and transmission removal, clutch packs, distributor and control valves, hydraulic pumps, heat exchanger, drive shaft, central bevel gear, steering clutches and brakes, final drives, track chains, recoil/adjuster assemblies, idlers, rollers, and track frames. The hydraulic section covers the tank and filters, main pump, control valve, lift and tilt cylinders, HSU blade, angledozer C-frame, quick-release valve, and ripper.

The 9.5 L turbocharged six-cylinder engine is rated at 177 kW at 2100 rpm with 101 daNm maximum torque at 1400 rpm. Valve clearances are 0.25 mm intake and 0.50 mm exhaust; injection timing is 23° ±30 minutes before top dead center, and injector setting is 260–268 bar. The torque converter has a 3.28:1 maximum stall ratio. Shop checks specify 14–15.5 bar for the engaged powershift ranges, up to 38 bar steering pilot pressure, 24 bar maximum brake pressure, 212 L/min main hydraulic pump flow, and 185–195 bar implement operating pressure.

Several details matter during an actual repair. Cylinder-liner protrusion is controlled to 0.040–0.070 mm; incorrect shim selection or reused liner water seals can compromise head sealing and allow coolant leakage. The transmission clutch packs contain compressed springs and call for dedicated compression fixtures—improvised release can distort retainers or damage clutch components. The grease-charged track adjuster and recoil spring are stored-energy assemblies; incorrect disassembly can damage the adjuster components and release parts under force. These warnings sit alongside the measurements, test points, and special-tool numbers needed to plan the work before the machine is opened.