Caterpillar 120G Motor Grader 4HD 3304 Engine Service Manual – Complete Workshop Guide

Caterpillar 120G Motor Grader 4HD 3304 Engine Service Manual

The Caterpillar 120G Motor Grader 4HD 3304 Engine Service Manual is the complete workshop reference for the 120G Motor Grader 4HD00001-UP machine powered by the 3304 engine. This 2569-page PDF combines disassembly and assembly procedures, specifications, systems operation, testing and adjusting, and troubleshooting information needed to service, repair, and maintain this motor grader across its major systems. Whether you are removing an air compressor, rebuilding a cylinder head, diagnosing a transmission fault, or adjusting the brakes, this Caterpillar 120G Motor Grader service manual provides the step-by-step procedures and technical data to do the job correctly.

File Details

• Manual Type: Complete Service Manual (Disassembly and Assembly, Specifications, Systems Operation, Testing and Adjusting, Troubleshooting)
• Brand: Caterpillar
• Model: 120G Motor Grader 4HD
• Configuration: 120G Motor Grader 4HD00001-UP (MACHINE)
• Engine: 3304 Engine
• Language: English
• Page Count: 2569 pages
• File Format: PDF
• Media Numbers: SENR5598-09, SENR3607-00, SENR3606-00, SENR3334-02, SENR5664-27, SENR3650-00, SENR3649-00, SENR3555-01, SENR3556-01, SENR3557-01, SENR3488-03, SENR3489-03, SENR2945-08, SENR4239-00, SENR4978-00, RENR1252-01, RENR8143-05, RENR7911-13, UENR7061-00, SENR3130-19
• Publication Dates: Multiple (1987 to 2017 as visible in the document)

Chapters Covered

• 3304B and 3306B Engines – Disassembly and Assembly: Air Compressor, Engine Balancer Shaft, Engine Balancer Shaft Bearings, Camshaft, Camshaft Bearings, Crankshaft Rear Seal, Crankshaft Front Seal, Crankshaft Main Bearings, Bearing Clearance Check, Spacer Plate, Cylinder Liner, Piston Cooling Jets, Pistons and Connecting Rods, Connecting Rod Bearings, Crankshaft, Cylinder Head, Inlet and Exhaust Valves, Valve Guides, Valve Seat Inserts, Turbocharger, Fuel Ratio Control, Fuel Injection Pump Housing and Governor, Fuel Injection Lines, Fuel Injection Nozzles, Fuel Injection Pump, Fuel Priming Pump, Fuel Transfer Pump, Fuel Shutoff Solenoid, Fuel Tank, Engine Oil Filter Base, Engine Oil Pump, Engine Oil Cooler, Water Temperature Regulator, Water Directors, Water Pump, Exhaust Manifold, Front Housing, Flywheel Housing, Flywheel, Gear Group (Front), Vibration Damper and Pulley, Compression Brake, Rocker Shaft, Lifter Group, Automatic Timing Advance, Governor, and related components
• 120G, 130G & 140G Motor Graders Air System & Brakes: Systems Operation, Testing and Adjusting, Specifications
• Air Dryer: Systems Operation, Specifications, Disassemble and Assemble
• Electrical System: 26SI Series Alternator, Delco Remy 20-SI Series Alternator, Electronic Monitoring System, MSS3s Machine Security System, Product Link PL522/523 and 121S/300
• Hydraulic System & Steering: Specifications, Systems Operation, Testing and Adjusting, Disassembly and Assembly (Priority Valve, Combination Valve, Steering Accumulator, Steering Metering Pump, Control Valves, Cylinder Groups, Hydraulic Pump, Hand Metering Unit, Circle Drive, and more)
• Power Train: Specifications, Systems Operation, Testing and Adjusting, Disassembly and Assembly (Transmission, Differential, Final Drives, Tandem Housings, Drive Chains, Axles, Transfer Gears, Transmission Hydraulic Controls, Relief Valves, and more)
• Vehicle Systems: Air Conditioning and Heating (R-12 and R134a), Wheel Spindles, Steering Cylinders, Wheel Lean, Blade Lift, Blade Tip, Centershift, Circle Drawbar, Front Axle, Main Frames, and related systems
• Torque Specifications: Metric (ISO) and English (SAE) fasteners, fittings, plugs, and general torque procedures

IMAGES PREVIEW

This Caterpillar 120G Motor Grader 4HD service manual is structured around the real service tasks a technician faces on this machine. The 3304 engine section walks through component removal and installation for the major engine assemblies, including the air compressor, balancer shafts, camshaft, crankshaft seals and bearings, cylinder liners, pistons and connecting rods, cylinder head, valves, turbocharger, and the complete fuel system. The power train coverage addresses the transmission, differential, final drives, tandem housings, drive chains, and axles, with specifications and testing procedures for each. The hydraulic system and steering section covers the priority valve, combination valve, steering accumulator, steering metering pump, control valves, cylinders, and hydraulic pump. Brakes and air system coverage includes the air compressor, governor, air dryer, control valves, rotochamber, and service brake components. Electrical coverage includes the alternator systems, Electronic Monitoring System, Machine Security System, and Product Link.

The manual also includes detailed specifications sections with capacities, torque values, pressure settings, and service limits, plus torque specifications for metric and SAE fasteners, fittings, and plugs. Systems Operation sections explain how the major systems work, while Testing and Adjusting procedures provide the diagnostic and adjustment steps needed to verify and correct system performance. The troubleshooting sections help identify and resolve common problems across the engine, power train, hydraulic, electrical, and air systems.

What This Manual Enables You to Do

With this Caterpillar 120G Motor Grader 4HD 3304 Engine Service Manual, you can perform the full range of service and repair tasks on the 120G Motor Grader 4HD00001-UP machine. The manual supports engine disassembly and assembly, including cylinder head work, valve service, piston and connecting rod replacement, crankshaft and bearing service, camshaft and balancer shaft work, and fuel system repair. It covers transmission and power train repair, differential and final drive service, drive chain replacement, axle removal and installation, and tandem housing work. Hydraulic and steering system coverage enables you to service the priority valve, combination valve, steering accumulator, steering metering pump, control valves, cylinders, and hydraulic pump. Brake and air system procedures cover the air compressor, governor, air dryer, control valves, rotochamber, and service brakes. Electrical system coverage includes alternator service, Electronic Monitoring System diagnostics, Machine Security System configuration and troubleshooting, and Product Link installation and diagnostics.

Having the correct procedures and specifications is critical when working on a Caterpillar motor grader. The torque values, pressure settings, clearances, and adjustment procedures in this manual are specific to the 120G Motor Grader 4HD with the 3304 engine. Using the correct specifications helps prevent component damage, ensures proper system operation, and supports safe machine operation. Whether you are a professional technician, a fleet maintenance manager, or an owner performing your own repairs, this manual provides the technical information needed to complete the job correctly.

Delivery Information

This Caterpillar 120G Motor Grader 4HD service manual is delivered as an instant PDF download after payment. No shipping is required. The PDF can be viewed on any device, including computers, tablets, and smartphones, and can be printed for use in the shop. With 2569 pages of detailed procedures, specifications, and illustrations, this manual is a complete reference for the 120G Motor Grader 4HD00001-UP machine.