1977–1981 Yanmar YM135/YM135D, YM155/YM155D, YM195/YM195D, YM240/YM240D & YM330/YM330D Tractor Shop Manual

This shop manual covers the 1977–1981 Yanmar YM135, YM155, YM195, YM240, and YM330 tractors, including the corresponding D-series four-wheel-drive models.

PDF Search, Wiring Detail and Included Pages

Text search and diagram detail: PDF text search and embedded bookmarks are not available. Small labels in the wiring diagrams are blurred, and some wire-color and terminal markings remain difficult to distinguish when enlarged.

Supplied in English as one printable 62-page PDF, comprising 61 manual pages, including the opening model/index page, and one decorative closing page already included in the total. The closing page contains no service information.

Diesel Overhaul, Drivetrain Service and Hydraulic Testing

These selected topics sit alongside additional material on decompression-control adjustment and front-axle toe-in checks.

• Engine repair: Step-by-step procedures for tractor splitting, engine removal, cylinder-head service, valve-seat reconditioning, timing-gear work, and inspection of internal engine components.

• Diesel fuel system: Bleeding procedures, injection-pump timing and replacement, nozzle testing and overhaul, governor adjustments, and checks of the Thermostart starting aid.

• Transmission and PTO: Gearbox disassembly and assembly, clutch adjustment, differential-lock service, and separate YM330 instructions for live-PTO and non-live-PTO versions.

• Axles, steering, and brakes: Front-drive housing overhaul, bevel-gear setup, rear-axle service, steering-gear disassembly, and brake inspection and adjustment.

• Hydraulic lift: Relief-pressure and flow testing, rockshaft fault diagnosis, lift-cycle checks, and YM330 linkage adjustments for position-control and draft-control systems.

• Electrical system: Wiring diagrams for the different model groups, charging-component identification, starter inspection specifications, and clutch-operated starting-safety-switch adjustment.

The repair material suits mechanics familiar with tractor splitting and precision measurement; injector work beyond assembly replacement requires the specialized equipment and training described in the manual.

Engine Overhaul, Cooling and Lubrication

Engine inspection data cover cylinder-liner stand-out, piston-ring gaps, connecting-rod and main-bearing clearances, valve guides, rocker arms, and crankshaft end play. Separate procedures address the two-cylinder crankshafts and the three-cylinder YM330 arrangement.

Cooling and lubrication: Coverage distinguishes the smaller tractors from the models with belt-driven water pumps. Water-pump instructions address removal and complete assembly replacement; oil-pump material covers internal inspection and pressure-relief checks.

Component torque specifications and cooling, engine-oil, and transmission/hydraulic capacities accompany the service procedures in metric and U.S. units.

Injection Pump and Nozzle Service

Injector tests address opening pressure, spray quality, and seat and back leakage. Fig. 89 provides an injection-pump section view, while the pump procedures cover removal, installation, and timing; further internal pump disassembly is not recommended.

The nozzle-overhaul section cautions that excessive retaining-nut torque can distort the assembly and make the valve stick. Tightening cannot correct leakage caused by dirt or scratched surfaces.

Clutch, Transmission and Differential Setup

Transmission work is divided into YM135/YM155, YM195/YM240, and YM330 sections. The YM330 material separates the two-stage live-PTO clutch shown in Fig. 135 from the non-live-PTO assembly, with corresponding differences in transmission-shaft service.

Front-drive configurations: Gear identification accounts for the tractor model and tire combination. Axle cross-sections and exploded drawings accompany the overhaul instructions and show the applicable bearings, seals, and shim arrangements.

Differential measurement: Figs. 191 and 196 specify different checking mandrels for the YM195/YM240 and YM330 groups. Their model-specific dimensions help a mechanic prepare the correct measuring setup before adjusting pinion position and ring-gear backlash.

Hydraulic Lift Testing and Fault Diagnosis

YM330 position-control and draft-control systems receive separate pressure, flow, and linkage checks. Troubleshooting connects slow lifting, failure to lower, and lift-arm drop after shutdown with possible filter, valve, seal, or pump faults.

Fig. 254 shows the position-control rockshaft and control valve in section. Hydraulic-pump service is limited to removal and replacement; internal overhaul is not recommended.

Tractor splitting and hydraulic or injector testing involve heavy components and pressurized fluid. Follow the precautions accompanying those procedures.

Charging Circuits and Starter Identification

Wiring diagrams in Figs. 128 and 129 distinguish the smaller tractors’ current-limiter circuits from the alternator and voltage-regulator arrangement used on larger models.

Starter information addresses standard units and optional gear-reduction versions. Identification by the installed starter’s data plate is required before choosing service specifications or replacement parts.

Cylinder-Liner and Piston-Ring Data Preview

YM195/YM195D cylinder liners: The engine inspection data specify a new liner inside diameter of 84.000–84.035 mm and a wear limit of 84.2 mm. Liner stand-out above the cylinder block is listed at 0.07–0.15 mm.

Piston-ring inspection: For those same models, the desired end gap for all rings is 0.3–0.5 mm, with a wear limit of 1.5 mm.