Komatsu PC40MR-2, PC40MRx-2, PC50MR-2 & PC50MRx-2 (2003) Excavator Operation & Maintenance Manual (P/N SEAM055301T)

Komatsu’s October 2003 Operation & Maintenance Manual (P/N SEAM055301T) covers the GALEO PC40MR-2 and PC40MRx-2 from serial number 8001, and the PC50MR-2 and PC50MRx-2 from serial number 5001. It documents machine operation, scheduled maintenance, and initial troubleshooting.

PDF Search, Bookmarks & Page Count

Text search and navigation: Most manual text is searchable, and embedded bookmarks lead to chapters and individual procedures. The introductory warranty and engine-label pages and some text within illustrations fall outside text search. The legacy MAIN MENU bookmark requires a separate HTML file. Small labels in the booster-cable drawings are easier to read with zoom.

The 266-page download is one printable PDF. It includes 265 manual pages and one additional front page, all counted in the total. The manual is in English, with French also appearing on the Canadian warranty and engine-label pages.

Excavator Controls, Scheduled Service & Fault Checks

These selected topics show the scope of the manual. Other examples include towing the excavator and operating the windshield washer on cab-equipped machines.

• Engine and fuel system: Engine oil and filter service, single- and double-element air-cleaner maintenance, water-separator cleaning, and fuel-system bleeding.
• Hydraulic maintenance: Oil and filter changes, tank-strainer cleaning, and air bleeding for the piston pump, cylinders, and fitted attachments.
• Tracks and bucket: Track-tension inspection and adjustment, rubber-shoe replacement, bucket replacement, and bucket-tooth and lock-pin inspection.
• Electrical troubleshooting: Battery removal and charging, fuse capacities and circuit assignments, and problem, cause, and remedy tables for starting and charging faults.
• Controls and attachments: Floor tilting, optional pattern-selector valve operation, attachment hydraulic connections, and bucket compatibility for standard and long arms.
• Service references: Maintenance schedules, lubricant and coolant specifications, fluid capacities, tightening torque tables, and the Safety Critical Parts List.

Komatsu specifies that trained and authorized personnel should operate and maintain the machine.

Operating Controls, Cab & Canopy

The operation chapter covers pre-start inspections, slope travel, demolition precautions, trailer loading and securement, and storage. It distinguishes the cab and canopy floor-locking arrangements and explains emergency exit through the cab window using the escape hammer. The control-pattern illustrations show the ISO and backhoe layouts for machines equipped with the selector valve.

Always review the included hazard guidelines and safety-label illustrations before operating or servicing the excavator.

Engine, Cooling & Scheduled Maintenance

The Maintenance Schedule Chart links routine service to the applicable procedures. Engine and cooling coverage includes fan-belt adjustment, radiator and oil-cooler fin cleaning, and cooling-system flushing. The manual also covers final-drive case oil service and shows the lubrication points for the swing circle, swing pinion, and bucket and arm cylinder pins.

Fluid references distinguish total system capacity from routine refill capacity and illustrate the engine-oil dipstick and coolant sub-tank marks. Separate tables cover antifreeze mixing ratios, metric fastener torque, and hydraulic hose fitting torque.

Hydraulics, Undercarriage & Bucket Service

The breaker maintenance chart ties hydraulic oil and filter replacement intervals to the share of operating time spent using the breaker. The bleeding section warns that running the pump with an unfilled case can damage the pump and that trapped air can damage cylinder piston packing.

The track procedures give separate inspection and adjustment criteria for rubber shoes, steel shoes, and road liners. Individual road-liner replacement calls for a special removal tool. Komatsu directs owners to a distributor for replacement of the full set. The bucket replacement procedure addresses shim placement and protecting O-rings and bushing dust seals during pin work.

Attachment Connections & Cab Options

The attachment chapter distinguishes North American quick-coupler plumbing from Australia and New Zealand stop-valve plumbing. It illustrates the connections and explains one-way breaker operation and two-way operation for crushers and other attachments. The bucket compatibility table shows that the listed narrow buckets fit both arm configurations, while the listed standard buckets require the standard arm.

Optional air-conditioning coverage includes condenser cleaning, compressor-belt adjustment, fresh-air and recirculation-filter cleaning, and refrigerant checks through the sight glass.

Troubleshooting & Repair Scope

The fuse table distinguishes cab and canopy circuits, including the engine stop solenoid and monitor panel. The fault tables address running out of fuel, abnormal exhaust smoke, slow hydraulic movement, and overheating. The travel-speed boost indicator can stay lit when increased load automatically shifts the machine to low travel speed. The operation chapter explains this behavior so operators can recognize it during a fault check.

Electrical references consist of fuse tables, fault tables, and battery-connection drawings. The manual directs valve-clearance adjustment and alternator or starter inspection and repair to a Komatsu distributor. Internal engine and hydraulic-component overhaul require separate service documentation.

Examples of Belt Inspection Specifications

For the cooling fan belt inspection, Komatsu specifies approximately 9–13 mm of deflection under about 98 N of force midway between the crankshaft and fan pulleys. For the optional air-conditioning compressor belt inspection, it specifies 5–6 mm under about 58.8 N midway between the idler and compressor pulleys.