Takeuchi TB68 Compact Excavator 1996–2008 Workshop Manual (P/N 34556-00001)

This 208-page PDF is the Takeuchi factory workshop manual for the TB68 compact excavator. Written for personnel engaged in maintenance operations, it is suited to technicians and experienced mechanics equipped to handle suspended assemblies, high-pressure hydraulic work, and pump testing. The publication combines service precautions, machine specifications, illustrated removal and installation routines, hydraulic-unit repair data, and symptom-based hydraulic diagnosis.

• TB68 coverage and configuration data: Factory tables distinguish standard-machine dimensions, long-arm operating ranges, standard and wide-shoe data, and standard versus optional bucket configurations.
• Lower machinery procedures: Covers crawler-belt, carrier-roller, track-roller, travel-motor, front-idler, track-spring, and dozer-blade removal and installation, including positioning, seal, and shim notes used during repair.
• Attachment and slew work: Details removal and installation of the hoe attachment, turntable and slew bearing, swivel joint, bucket, arm, boom, boom bracket, and related cylinders, with centering and clearance adjustments where required.
• Upper machinery access: Maps work on the seat, cabin, covers, heater, fuel and hydraulic tanks, main pump, main and sub control valves, engine and radiator, control boxes, slew gearbox, control levers, and swing cylinder.
• Main-pump overhaul: Provides tandem-pump disassembly and assembly, bearing and seal work, shaft-end-play adjustment, post-assembly leak and performance testing, plus torque-control and power-match valve adjustment.
• Hydraulic fault isolation: Uses diagnostic flowcharts for total function loss, low power, one-sided travel faults, poor straight travel, slew failure or overrun, and boom, arm, bucket, boom-swing, and dozer-cylinder symptoms.
• Technical reference material: Includes hydraulic and electrical circuit diagrams, component section views, fitting and bolt torque tables, pressure-test and performance standards, capacities, lubricants, clearances, and wear limits.

Mechanical and Hydraulic Documentation

The general section establishes shop practices for hydraulic-unit and piping removal, seal handling, hose-fitting, pipe-fitting, and bolt torque tables, cylinder air bleeding, and hydraulic-tank pressurization. It also explains how the manual's disassembly maps work: horizontally arranged items define the required order, while vertically grouped items may be removed independently. That matters on jobs such as slew-bearing or swivel-joint access, where the hoe attachment, cabin, covers, seat, and turntable are removed in a defined dependency chain.

The hydraulic chapter goes well beyond a circuit overview. It explains the tandem swash-plate axial-piston main pump, gear-type sub pump, pressure-compensated main control valve, two-section sub control valve, relief-and-unload valve, slew/swing selector valve, breaker shut-off valve, pressure-reducing joystick controls, cylinders, and the axial-piston slew motor with counterbalance, shockless, and relief valves. Main-pump service includes a tool list and dimensioned drawings for the bearing, oil-seal, shaft-end-play, and support jigs.

The manual calls out two easy-to-miss repair hazards. The slew bearing's marked weak section must not be positioned at the front or rear, where loading can damage the bearing, and failure to re-pressurize the hydraulic tank after unit installation can cause pump cavitation and sharply reduce pump life. Because these jobs involve heavy attachments and stored hydraulic pressure, suspended components must be supported and tank pressure relieved before lines are opened; crane and hoisting work is assigned to qualified personnel.

Engine, Specifications, and Diagnostic Data

The engine reference identifies the Nissan SD3304, a four-cycle, water-cooled overhead-valve swirl-chamber diesel. Machine-side coverage includes radiator removal and positioning, wiring and accelerator disconnection, engine lifting, engine mounts, and the sub pump. This is not an internal SD3304 repair or overhaul manual; cylinder-head, fuel-injection, timing, and internal engine procedures are outside its documented scope.

The specification section provides dimension and operating-range diagrams, front and side lifting charts, component pressure and displacement specifications, fluid capacities, and recommended lubricants. It also supplies factory check standards for travel, slew, and cylinder speed or drift, plus lever force and play, slew-bearing backlash, crawler tension, pin and bushing wear, lower-machinery wear, and bucket-tooth limits.

Named visual references include the Hydraulic Circuit Diagram, Electrical Circuit Diagram, main-pump Section A-A, main-control-valve pressure-compensation views, slew-motor counterbalance and shockless-valve diagrams, and symptom flowcharts. The electrical sheet covers starting, charging, glow, engine shutdown, instruments and warnings, lighting, wiper, heater, safety-relay, and optional cooler circuits. Electrical coverage is schematic only; the dedicated troubleshooting section is hydraulic and does not provide a separate electrical diagnostic chapter.