Complete workshop repair service manual with electrical wiring diagrams for Caterpillar 300.9D Mini Hydraulic Excavator. It's the same service manual used by dealers that guaranteed to be fully functional and intact without any missing page.

This service manual for Caterpillar 300.9D Mini Hydraulic is divided into different sections. Each section covers a specific component or system with detailed illustrations. A table of contents is placed at the beginning of each section. Pages are easily found by category, and each page is expandable for great detail. The printer-ready PDF documents work like a charm on all kinds of devices.

UENR5416 - Schematic (300.9D Mini Hydraulic Excavator Electrical System)
UENR0478 - Specifications (300.9D Mini Hydraulic Excavator)
UENR0478 - Systems Operation (300.9D Mini Hydraulic Excavator)
UENR0478 - Testing & Adjusting (300.9D Mini Hydraulic Excavator)
UENR1774 - Schematic (300.9D Mini Excavator Hydraulic System)
UENR2937 - Specifications (300.9D VPS Mini Hydraulic Excavator Machine Systems)
UENR3279 - Disassembly & Assembly (3TNV70 & 3TNV76 Engines for Caterpillar Built Machines)
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UENR0478 - Specifications (300.9D Mini Hydraulic Excavator)......2
  Bank Valve......4
  Blade Cylinder......11
  Blade Valve and Mounting......12
  Blade and Mounting......14
  Boom Cylinder......16
  Bucket Cylinder......18
  Check Valve......19
  Connecting Rod......20
  Counterweight......22
  Cylinder Head......24
  Engine Design......27
  Engine Mounting......31
  Exhaust System......33
  Flywheel Housing......35
  Fuel Injection Nozzles......37
  Fuel Injection Pump......41
  Fuel Tank......54
  Hydraulic Tank......56
  Main Bearing Journal......58
  Main Hydraulic Pump Mounting......60
  Main Hydraulic Pump......62
  Oil Filter (Hydraulic)......64
  Oil Pan......65
  Open Rollover Protective Structure (ROPS)......67
  Relief Valve (Line)......69
  Starter Motor......70
  Stick Cylinder......72
  Stick......73
  Swing Cylinder......75
  Swing Frame......76
  Swing Motor......80
  Track Tension Cylinder......82
  Track......83
  Travel Motor......85
  Undercarriage Cylinder (Adjustable Gauge)......87
  Undercarriage Frame (Adjustable Gauge)......90
UENR0478 - Systems Operation (300.9D Mini Hydraulic Excavator)......92
  Auxiliary Hydraulic System......93
  Blade Hydraulic System......100
  Boom Hydraulic System......106
  Bucket Hydraulic System......111
  Engine Speed Control - Altitude Sensor (If Equipped)......116
  Fuel System......119
  Gear Pump......121
  General Information......123
  Main Control Valve 01_04_2014......126
  Main Control Valve......128
  Return Hydraulic System......134
  Stick Hydraulic System......138
  Swing Boom Hydraulic System......143
  Swing Hydraulic System......150
  Swivel......154
  Travel System......156
  Undercarriage Cylinder (Adjustable Gauge)......163
UENR0478 - Testing & Adjusting (300.9D Mini Hydraulic Excavator)......167
  Basic Engine......168
  Compression - Test......172
  Coolant Temperature Switch - Test......174
  Cooling System - Check......176
  Cylinder Drift - Check......181
  Cylinder Speed - Check......187
  Engine Oil Pressure Switch - Test......209
  Engine Valve Lash - Inspect_Adjust......211
  Fuel Injection Nozzle - Test......215
  Fuel Injection Timing - Check_Adjust......218
  Hydraulic System Pressure - Release......234
  Hydraulic System Troubleshooting......236
  Relief Valve - Test and Adjust......237
  Specifications......245
  Travel on Level Ground - Test......251
  Water Temperature Regulator - Test......254
UENR1774 - Schematic (300.9D Mini Excavator Hydraulic System)......256
  Collage......257
  Main......269
UENR2937 - Specifications (300.9D VPS Mini Hydraulic Excavator Machine Systems)......271
  Bank Valve......273
  Blade Cylinder......280
  Blade Valve and Mounting......281
  Blade and Mounting......283
  Boom Cylinder......285
  Bucket Cylinder......286
  Check Valve......287
  Connecting Rod......288
  Counterweight......290
  Cylinder Head......292
  Engine Design......295
  Engine Mounting......297
  Exhaust System......299
  Flywheel Housing......301
  Fuel Injection Nozzles......303
  Fuel Injection Pump......307
  Fuel Tank......316
  Hydraulic Tank......318
  Main Bearing Journal......320
  Main Hydraulic Pump Mounting......322
  Main Hydraulic Pump......324
  Oil Filter (Hydraulic)......326
  Oil Pan......327
  Open Rollover Protective Structure (ROPS)......329
  Relief Valve (Line)......331
  Starter Motor......332
  Stick Cylinder......334
  Stick......335
  Swing Cylinder......337
  Swing Frame......338
  Swing Motor......340
  Track Tension Cylinder......342
  Track......343
  Travel Motor......345
  Undercarriage Cylinder (Adjustable Gauge)......347
  Undercarriage Frame (Adjustable Gauge)......350
UENR3279 - Disassembly & Assembly (3TNV70 & 3TNV76 Engines for Caterpillar Built Machines)......352
  Alternator - Remove and Install......354
  Bearing Clearance - Check......356
  Camshaft and Valve Lifters - Remove and Install......359
  Connecting Rod Bearings - Remove and Install......361
  Coolant Temperature Sensor - Remove and Install......363
  Crankshaft Front Seal - Remove and Install......365
  Crankshaft Pulley - Remove and Install......367
  Crankshaft Rear Seal - Remove and Install......369
  Crankshaft and Main Bearings - Install......372
  Crankshaft and Main Bearings - Remove......376
  Cylinder Head - Remove and Install......379
  Electric Starting Motor - Remove and Install......382
  Engine Oil Pan - Remove and Install......384
  Engine Oil Pressure Sensor - Remove and Install......387
  Engine Oil Pump - Remove and Install......388
  Engine Oil Relief Valve - Remove and Install......391
  Exhaust Manifold - Remove and Install......393
  Flywheel - Remove and Install......395
  Flywheel Housing - Remove and Install......397
  Fuel Injection Lines - Remove and Install......399
  Fuel Injection Pump - Remove and Install......402
  Fuel Injector - Remove and Install......407
  Glow Plugs - Remove and Install......409
  Housing (Front) - Remove and Install - Internal......412
  Housing (Front) - Remove and Install......415
  Idler Gear - Remove and Install......417
  Inlet and Exhaust Valve Guides - Remove and Install......421
  Inlet and Exhaust Valve Springs - Remove and Install......423
  Inlet and Exhaust Valves - Remove and Install......427
  Pistons and Connecting Rods - Assemble......431
  Pistons and Connecting Rods - Disassemble......436
  Pistons and Connecting Rods - Remove and Install......439
  Rocker Arm - Assemble......443
  Rocker Arm - Disassemble......445
  Rocker Arm and Shaft - Remove and Install......447
  Valve Mechanism Cover - Remove and Install......450
  Water Pump - Remove and Install......452
  Water Temperature Regulator - Remove and Install......454
UENR5416 - Schematic (300.9D Mini Hydraulic Excavator Electrical System)......456
  Collage......457
  Main......469

EXCERPT:
Cooling System - Check
This engine has a pressurized cooling system. A pressurized cooling system has two advantages. The cooling system can be operated in a safe manner at a temperature higher than the normal boiling point (steam) of water.
This type of system prevents cavitation in the water pump. Cavitation is the forming of low-pressure bubbles in liquids that are caused by mechanical forces. The formation of an air pocket or a steam pocket in this type of cooling system is difficult.
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Caterpillar 300.9D Mini Hydraulic Factory Service & Shop Manual