Komatsu PC128US-2 PC138US-2 PC138USLC-2 Excavator Shop Manual PDF Download

Description

Komatsu PC128US-2, PC138US-2 and PC138USLC-2 Excavator Shop Manual

This Komatsu PC128US-2 PC138US-2 PC138USLC-2 Excavator Shop Manual PDF Download is the complete service and repair documentation for three Komatsu hydraulic excavator models. It is organised into six major chapters that take a technician from general specifications through to full component disassembly, testing procedures, maintenance limits, hydraulic circuit diagrams and electrical schematics. The manual covers PC128US-2 (serial 5001 and up), PC138US-2 (serial 4501 and up) and PC138USLC-2 (serial 1001 and up), fitted with either the Komatsu S4D102E or SAA4D95LE engine.

File Details

• Manual type: Komatsu Shop Manual
• Brand: Komatsu
• Models covered: PC128US-2, PC138US-2, PC138USLC-2
• Serial numbers: PC128US-2 5001 and up; PC138US-2 4501 and up; PC138USLC-2 1001 and up
• Engines: S4D102E, SAA4D95LE (engine details are covered in the 102 Series and 95 Series Engine Shop Manuals referenced in this book)
• Language: English
• Page count: 1045
• File format: PDF
• Document number: SEBM018419 U0412

Chapters Covered

The Komatsu PC128US-2 PC138US-2 PC138USLC-2 shop manual is divided into the following top-level chapters, each with detailed sub-sections:

• 01 General — general assembly drawings, specifications, weight tables, list of lubricants and water, unit conversion tables, safety notices, standard tightening torques, electric wire code, hoisting instructions
• 10 Structure and Function — engine control, cooling system, undercarriage (idler, recoil spring, track roller, track shoe), swing machinery, swing circle, travel motor, final drive, centre swivel joint, hydraulic pump (HPV95 piston pump), LS valve, PC valve, control valve (7-spool and 9-spool), pressure compensation valves, main relief valve, PPC valves, solenoid valves, self pressure reducing valve, boom drift prevention valve, arm regeneration valve, hydraulic cylinders, air conditioner piping, electric component layout, monitor system, electric control system
• 20 Testing and Adjusting — standard value tables for engine and chassis, measuring engine speed and exhaust colour, adjusting valve clearance, measuring blow-by pressure and engine oil pressure, testing and adjusting fuel injection timing, fan belt tension, engine speed sensor, fuel control cable, swing circle bearing clearance, sprocket wear, track shoe tension, hydraulic pressure tests for work equipment/swing/travel circuits, PC valve and LS valve output pressure tests, control circuit oil pressure, solenoid valve output pressure, PPC valve adjustment, travel deviation, hydraulic drift, oil leakage measurement, bleeding air, releasing residual pressure, electrical parts standard value tables, Pm clinic inspection tables
• 30 Disassembly and Assembly — cylinder head, injection pump, engine and main pump, radiator, hydraulic oil cooler, after cooler, fuel tank, centre swivel joint, swing motor and swing machinery, revolving frame, swing circle, travel motor and final drive, recoil spring, idler, track roller, track shoe, hydraulic tank, main pump, control valve, LS selection valve, pressure compensation valve, main relief valve, work equipment PPC valve, travel PPC valve, hydraulic cylinder, work equipment, operator cab, floor frame, air conditioner compressor, condenser and unit, counterweight, monitor panel, controller
• 40 Maintenance Standard — swing machinery, track frame, idler cushion, idler, track roller, sprocket, track shoe, hydraulic pump, control valve, hydraulic cylinders, work equipment
• 90 Others — hydraulic circuit diagrams (attachment configurations including breaker, crusher, service valves), electric circuit diagrams (air conditioner, machine, KUK spec), hydraulic circuit diagrams for various attachment and blade combinations

What This Komatsu Shop Manual Gives You

This is a full workshop manual, not a condensed owner’s guide. It contains the procedures and values a technician needs to diagnose, remove, disassemble, inspect, repair and reassemble every major system on the PC128US-2, PC138US-2 and PC138USLC-2. For each component the manual gives the structure and function first, then the testing and adjustment values, then the disassembly and assembly sequence, and finally the maintenance standard that defines wear limits and serviceability. Hydraulic and electrical circuit diagrams are included so that circuit-level fault finding can be carried out with reference to actual oil flow and wire routing.

Engine coverage is by reference: the S4D102E and SAA4D95LE engine details are in the separate 102 Series and 95 Series Engine Shop Manuals, and this chassis manual points there for internal engine work. Everything else — the hydraulic system, undercarriage, swing and travel functions, control valve, PPC controls, electrical monitoring and air conditioning — is covered in detail here.

Who This Manual Is For

This Komatsu PC128US-2 PC138US-2 PC138USLC-2 shop manual is intended for service technicians, workshop owners, fleet maintenance managers and knowledgeable owners who carry out their own repairs. It is equally useful for anyone who needs the correct specifications to judge whether a component is still within service limits or must be replaced. The testing and adjusting chapter in particular is written so that hydraulic pressures, servo piston input pressures, LS differential pressures and control circuit pressures can be measured and compared against standard values for the exact serial number range of the machine on the bench.

Coverage by Serial Number

Komatsu uses serial number breaks within this manual because specifications change across production. PC128US-2 is covered from serial 5001 and up, with separate data given for 5001–7730 and 7731 and up where applicable. PC138US-2 is covered from 4501 and up. PC138USLC-2 is covered from 1001 and up, with separate data for 1001–1500 and 1501 and up. The testing and adjusting tables and some hydraulic circuit diagrams are split accordingly, so the correct section must be selected for the machine in question.

Hydraulic and Electrical Diagrams Included

The 90 Others chapter carries the hydraulic circuit diagrams and electric circuit diagrams. Hydraulic diagrams are provided for standard configuration, for machines with blade, for machines with one or two actuator attachments, and for KUK specification. Electric circuit diagrams cover the air conditioner and the main machine circuits, again split by serial number range and specification. These diagrams are essential for tracing faults in the CLSS (Closed Centre Load Sensing System) hydraulic circuit, the PPC control circuits, the swing holding brake circuit and the travel speed selection circuit.

Why the Correct Manual Matters for This Machine

The PC128US-2, PC138US-2 and PC138USLC-2 use a load-sensing hydraulic system with LS and PC valve control of the main pump, pressure compensation valves in the control valve, and electronic control of pump absorption torque and engine speed. Adjusting the wrong screw or using the wrong pressure value can upset the balance between the LS valve, PC valve and servo piston, leading to slow operation, engine stall, excessive hydraulic drift or poor fine control. Having the correct testing sequence and standard values in front of you turns guesswork into a measurable procedure.

The disassembly and assembly chapter includes the tightening torques, coating materials, special tools and reassembly precautions for each component. The maintenance standard chapter gives the clearances, wear limits and repair limits that determine whether a part can be reused, reconditioned or must be replaced. Together these chapters support planned maintenance, breakdown repair and rebuild work.

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Instant PDF Delivery

This Komatsu PC128US-2 PC138US-2 PC138USLC-2 Excavator Shop Manual is delivered as a PDF download immediately after purchase. There is no shipping and no waiting for a physical book. The file can be opened on a workshop computer, laptop, tablet or smartphone, searched for a model or system, and printed page by page or as a complete section for use at the machine. Because the original file covers 1045 pages, it is practical to print only the chapter relevant to the job at hand and keep the rest on file.

If you maintain or repair a PC128US-2, PC138US-2 or PC138USLC-2, this Komatsu shop manual provides the structured technical information needed to carry out the work correctly — from routine track tension adjustment and hydraulic pressure testing through to control valve overhaul and swing machinery rebuild.