Komatsu PC50UU-2 Excavator Shop Manual – 2002 (P/N SEBM000906)

Komatsu PC50UU-2 shop manual, P/N SEBM000906, March 2002 edition, for mini excavators with serial numbers 8001 and up, including canopy and cab configurations. Serial-specific sections distinguish changes to the engines, hydraulics, travel motors, and electrical systems.

PDF Bookmarks, Diagram Detail, and Page Count

Navigation and readability: PDF text search is unavailable. Embedded bookmarks provide access to chapters and component procedures. Small connector numbers and wire codes in the electrical schematics require zooming.

One printable, English-language 828-page PDF, including the original cover, four revision-list pages, and 56 blank pages. The travel-motor repair sections are incorporated into this shop manual.

Hydraulic Repair, Travel Motors, and Machine Controls

These selected coverage highlights outline the main workshop content. Further topics include push-pull hydraulic couplers and one-touch deceleration control.

• Engine, fuel, and cooling: Engine and cylinder-head removal and installation, fuel-injection pump replacement, and procedures for the water pump, thermostat, radiator, and hydraulic oil cooler.

• Hydraulic components: Step-by-step disassembly and assembly instructions for the PVD-2B-42L3DPS main pump, 4-spool control valve, work-equipment PPC valve, and hydraulic cylinders.

• Travel and swing: GM05VL and GM06VL travel-motor overhaul, swing machinery repair, swing-circle replacement, and center swivel joint disassembly and assembly.

• Hydraulic diagnosis: Pressure testing, cylinder leakage checks, travel-deviation testing, swing and travel motor leakage measurements, and air-bleeding procedures.

• Electrical controls: Controller fault charts, solenoid and EPC valve tests, potentiometer replacement, input/output resets, and machine-monitor diagnosis.

• Undercarriage and work equipment: Rubber and steel shoe replacement, track-tension adjustment, roller and recoil-spring repairs, and boom, arm, bucket, and blade removal.

Written for service workshop personnel, this manual assumes access to hydraulic test equipment, electrical test adapters, lifting equipment, and component-specific service tools.

Engine Service and Overhaul Boundaries

Engine checks cover compression, oil pressure, valve clearance, fuel-injection timing, and fuel-control linkage adjustment. These procedures support servicing the installed 4D84-2GA and 4D88E-series engines and removing major assemblies.

Internal engine overhaul requires separate engine documentation. The cover directs readers to the 84 Series and 68E–88 Series Engine Shop Manuals for engine details; those separate manuals are not included.

Hydraulic Diagnosis and Component Repair

Power-train and PTO drawings distinguish the early SBR14+14+9 gear-pump arrangement from the PVD-2B-42L3DPS piston-pump arrangement used from S/N 12772. Structural sections explain the 4-, 5-, and 6-spool control valves, including the optional PTMA blade circuit, plus hydraulic tank valves and filtration.

The troubleshooting charts connect symptoms to checks before major components are dismantled. For travel deviation, the H-11 charts distinguish pump, control-valve, center swivel joint packing, and travel-motor faults rather than treating every tracking problem as a failed motor.

Hydraulic Piping Diagrams and serial-specific Hydraulic Circuit Diagrams show how these components connect. Cylinder leakage tests also distinguish internal cylinder leakage from control-valve faults when work equipment drifts.

The center swivel joint assembly instructions identify seal lips as damage-sensitive during rotor installation. The LMF16AB swing-motor procedures likewise address the risk of damaging brake-piston O-rings and backup rings during assembly.

Please note that working on high-pressure hydraulics carries inherent risks; follow the manual’s pressure-release and workshop safety precautions before opening hydraulic circuits.

Electrical Fault Tracing and Control Resets

Separate E-mode, H-mode, and M-mode charts address controller/electrical, hydraulic/mechanical, and machine-monitor faults. Electrical Circuit Diagrams for Each System, Connector Arrangement Drawings, and connector pin-number tables support tracing faults between sensors, wiring, and controllers.

The Four System sections explain interference prevention, depth measurement, height/depth automatic stopping, and offset positioning. Reset procedures distinguish the principal serial ranges and cover work-equipment, controller, and potentiometer replacement.

Attachment compatibility matters: Long-arm and slide-arm installation requires the appropriate selection wiring and control resets. The manual cautions that certain attachments and non-genuine long or slide arms can prevent the interference-prevention function from operating normally.

Monitor coverage includes diagnosis and removal/installation. Solenoid and EPC valve coverage includes operating principles, electrical checks, and outlet-pressure measurements.

Overhaul Checks and Workshop References

The travel-motor chapters go beyond removal: Sectional Drawings of Assembly, parts lists, clearance-adjustment tables, wear criteria, and performance-confirmation tests support inspection and reassembly of each motor type.

General assembly drawings and track-frame sections distinguish rubber and steel shoe configurations. Maintenance standards provide component inspection limits, while weight tables and special-tool sketches support planning removal and assembly work.

Reference sections retain standard tightening torques for bolts, flared nuts, and split-flange connections, alongside lubricant and water capacities, conversion tables, and hydraulic tank cracking-pressure specifications.

A Preview of Oil Capacities and Component Settings

The PC50UU-2 lubrication table distinguishes the engine oil pan’s 9.1 L specified capacity from its 8.5 L normal refill quantity. For the 4D84-2GA engine at S/N 8001–12771, the inspection table lists 0.2 mm intake and exhaust valve clearance at normal temperature.

The LMF40-2 swing motor used at S/N 8001–12771 has a listed safety-valve set pressure of 20.6 MPa (210 kg/cm2).