Target Audience:
Owners, technicians, and restoration enthusiasts of the Bobcat 643 skid steer loader.
Comprehensive Coverage:
Factory-level repair procedures, diagnostics, and specifications.
Digital Convenience:
Instant download, printable pages.
Detailed Procedures:
Step-by-step instructions for disassembly, inspection, and reassembly.
Troubleshooting Guides:
Diagnostic information for common issues.
Systems Covered:
Engine, transmission, hydraulics, electrical, chassis, and more.
Procedures Included:
Maintenance, repair, overhaul, and troubleshooting.
Page Count:
N/A - digital manual, page count not specified
Manual Type:
Service repair workshop manual
Delivery Method:
Instant download
Safety Information:
Warnings and precautions for safe operation and repair.
Maintenance Schedules:
Recommended service intervals for routine upkeep.
Engine Overhaul:
Disassembly, inspection, and rebuild procedures.
Fuel System:
Carburetor adjustment, fuel pump, and lines.
Cooling System:
Radiator, water pump, thermostat checks.
Lubrication System:
Oil pump, filter, and pressure checks.
Transmission and Drivetrain
Transmission:
Hydraulic drive system, chaincase adjustment.
Differential:
Service and adjustment.
Axles and Hubs:
Inspection, bearing replacement.
Hydraulic Pump:
Testing and replacement.
Hydraulic Cylinders:
Seal replacement and testing.
Control Valves:
Disassembly and adjustment.
Wiring Diagrams:
Schematic layouts for troubleshooting.
Starter and Charging:
Starter motor, alternator, battery checks.
Lighting and Indicators:
Inspection and wiring checks.
Chassis and Undercarriage
Chassis Frame:
Structural inspection, repair points.
Undercarriage:
Track adjustment, sprocket, idler wear.
Specifications:
Torque specs, fluid capacities, clearances.
Diagnostic Information:
Fault finding and testing procedures.
Exploded Views:
Diagrams for part identification.
Part Numbers:
Original Bobcat part numbers for ordering.
Compatibility:
All modern devices with PDF reader (Windows, Mac, iOS, Android).
Searchability:
Digitally searchable text
Print Quality:
High-resolution pages suitable for printing.
Binding Type:
Digital (no physical binding)
Paper Type:
N/A - digital manual
Engine Oil Change:
Every 100 hours or annually (typical)
Hydraulic Oil Change:
Every 500 hours (typical)
Air Filter Service:
Every 50 hours, replace as needed
Engine Oil:
SAE 10W-30 or 15W-40 (API classification unspecified)
Hydraulic Oil:
Use Bobcat hydraulic fluid or equivalent (ISO 46)
Coolant:
50/50 antifreeze-water mix
Known Issues / Wear Items
Drive Belts:
Check for wear and adjust tension.
Wheel Seals:
Inspect for leaks.
Hydraulic Hoses:
Inspect for cracks or abrasion.
Manufacturer:
Bobcat (part of Clark Equipment, later Ingersoll Rand, now Doosan Bobcat)
Evolution:
The 643 was part of Bobcat's M-series loaders introduced in the 1970s.
Manufactured In:
North Dakota, USA (Gwinner / Bismarck area)
