2003 Komatsu PC27MRX-1, PC30MRX-1, PC35MRX-1, PC40MRX-1 & PC45MRX-1 Excavator Shop Manual (P/N SEBM016808)

Komatsu factory shop manual SEBM016808, printed 08-03(02), covers PC27MRX-1 through PC45MRX-1 excavators in canopy and cab configurations, within the serial ranges listed above.

Supplied as one 947-page English PDF.

• Engine repair: Engine/main-pump removal, cylinder-head removal and installation, valve-clearance adjustment, compression and oil-pressure testing, and fuel-injection timing checks.

• CLSS hydraulics: Main-pump and control-valve disassembly, hydraulic relief and LS differential-pressure testing, PC-valve adjustment, and PPC/solenoid output checks.

• Swing and travel: Swing motor and swing machinery repair, holding-brake testing, center swivel joint service, and travel-deviation diagnosis and adjustment.

• Undercarriage and work equipment: Track-tension and sprocket-wear checks, idler/recoil and roller repair, hydraulic-cylinder rebuilding, and major work-equipment removal and installation.

• Electrical troubleshooting: E-mode fault charts, M-mode machine-monitor diagnosis, wiring diagrams, connector locations, pin-allocation drawings, and electrical test specifications.

• Hydraulic breaker: Service-valve testing and adjustment, breaker disassembly and assembly, and nitrogen-pressure testing and charging for the specified PC35/40/45 installations.

Written for service personnel carrying out workshop repairs, this manual includes procedures requiring hydraulic test equipment, factory special tools, and equipment for lifting heavy assemblies.

Engine Coverage and Serial-Specific Configurations

Engine coverage distinguishes the 3D82AE-3 family used on the PC27MRX-1, the 3D84E-3 family used on the PC30MRX-1 and PC35MRX-1, and the 4D84E-3/4D88E-3 families used on the PC40MRX-1 and PC45MRX-1. The PC30MRX-1 specification identifies the 3D84E-3K at 1,496 cc.

PC40 specifications split at serial 5501 and PC45 specifications at 3001, including the change from the 4D84E-3EC to the 4D88E-3HB engine. Hydraulic and control-system sections also distinguish these builds, including air-conditioned and non-air-conditioned configurations. Work-equipment performance tables separate canopy from cab/TOPS specifications where factory values differ.

This publication covers machine-side engine testing, adjustment, cylinder-head work, and engine/main-pump removal, but directs the technician to the separate 68E-88E Series Engine Shop Manual for detailed engine service. In drawings, PC27MR/PC30MR/PC35MR/PC40MR/PC45MR identify the corresponding MRX machines.

Hydraulic, Swing, and Travel Repair

The Structure and Function chapters explain the CLSS (Closed Center Load Sensing System), including variable-displacement piston pumps, PC and LS valves, and the servo piston. Control-valve coverage includes pressure-compensation valves, the unload valve, main relief system, PPC controls, and solenoid valves.

Disassembly and Assembly covers pump repair for the LPV30 in PC30MRX-1 and LPD25+25 in PC40MRX-1. Hydraulic air-bleeding procedures distinguish the components opened or replaced during repair. Cylinder internal-leakage tests support diagnosis of work-equipment drift.

The standard-value tables are model-specific: work-equipment/travel relief pressure is 22.06 ± 0.49 MPa on PC27MRX-1, 25.5 ± 0.49 MPa on PC30MRX-1, and 26.3 ± 0.49 MPa on PC35MRX-1. PC40MRX-1 and PC45MRX-1 have separate tables with different pressure tolerances and serial-specific control-pressure entries. Matching the table to the machine helps select the correct test conditions when investigating low hydraulic power.

The LMF16 swing motor is listed at a rated 1,165 rpm for PC27MRX-1/PC30MRX-1, 1,266 rpm for PC35MRX-1, and 1,820 rpm for PC40MRX-1/PC45MRX-1. Swing machinery oil capacity is approximately 0.9 L on PC27/30/35 and 1.3 L on PC40/45.

The swing-motor hydraulic timer delays brake application because sudden engagement can damage motor components. The PHV-500 travel-motor repair section warns that contamination between assembly parts can cause seizure; PC40/45 engine/main-pump removal also carries a specific warning about radiator-core damage during lifting.

H-mode troubleshooting addresses poor fine control, low power, hydraulic drift, travel deviation, swing overrun, pump noise, steering problems, and travel-speed switching. PC45 travel-motor drawings and maintenance standards distinguish serials 1001–2041 from 2042 and up.

Wear Limits, Workshop Data, and Special Tools

Maintenance Standard tables provide backlash, bearing-clearance, wear, and repair-limit data for the swing machinery, swing circle, track frame, idlers, carrier and track rollers, sprockets, and track shoes. Further tables cover the center swivel joint, hydraulic cylinders, and work-equipment pins and bushings.

The General section provides model-by-model lubricant and water tables with specified-versus-refill capacities, component-weight data, and standard tightening torques. Testing and Adjusting includes engine-speed and exhaust-smoke checks alongside the engine test specifications.

The special-tool lists identify the 790-501-5200 unit repair stand and 790-101-5001 push-tool kit for hydraulic-pump work. The 799-101-5130 gauge and 799-101-5160 nipple are listed for releasing the swing-motor brake during turning-torque measurement.

Schematics and Electrical Fault Finding

Representative drawings include the CLSS “Hydraulic Circuit Diagram and Name of Valve,” model-specific “Hydraulic Circuit Diagram,” and “Electrical Circuit Diagram — Cab Specification.” “Actual Electric Wiring Diagram,” “Air Conditioner Piping,” and “Machine Monitor System” drawings add component-location and system detail. Circuit sheets distinguish canopy, cab, EU, and USA configurations where applicable.

Electrical troubleshooting covers an engine that will not start or stop, a work-equipment lock that does not hold, and travel speed that will not increase or decrease. Connector, resistance, voltage, solenoid, relay, and harness checks are tied to the related circuit diagrams.

M-mode diagnosis addresses monitor self-checks, warning lamps, coolant-temperature and fuel gauges, the alarm buzzer, and service meter. An electric wire-code chart covers conductor size, current rating, circuit classification, and color coding.

Because these excavators use high-pressure hydraulic circuits and heavy assemblies, follow the manual’s specified pressure-release, blocking, lifting, and battery-isolation precautions before beginning service.

PDF Search, Bookmarks, and Diagram Readability

The total includes 946 manual pages plus one added cover page; the factory cover, revision lists, and circuit sheets are already included. Text search is partial: 300 pages have no embedded text, and some schematic labels cannot be searched. Bookmarks cover the technical sections, but the Foreword entry is misdirected and the Main Menu link requires a separate file; small connector, pin, and wire-code labels on large circuit sheets require zooming to read comfortably.