Keeping the Bobcat 743 Running Strong After Decades of Service

[MikePhua]

The Bobcat 743 and Its Place in Compact Loader History
The Bobcat 743 skid steer loader was introduced in the early 1980s as part of Bobcat’s 40-series lineup, which marked a turning point in compact equipment design. With an operating weight of around 4,800 lbs and a rated operating capacity of 1,300 lbs, the 743 was powered by a 36-horsepower Kubota V1702 diesel engine. It featured a chain-driven transmission, open-center hydraulics, and mechanical hand-and-foot controls. The machine quickly gained popularity among landscapers, farmers, and contractors for its simplicity, reliability, and ease of maintenance.
Bobcat, originally Melroe Manufacturing, had already revolutionized the compact loader market in the 1960s. By the time the 743 was released, the company had sold tens of thousands of units globally. The 743 became a staple in rental fleets and private yards, often outlasting newer models thanks to its mechanical robustness.
Common Maintenance Challenges and Solutions
Owners of aging 743s often face predictable issues:

• Hydraulic leaks
  Seals around lift and tilt cylinders degrade over time. Rebuilding cylinders with new seal kits restores pressure and prevents contamination.
  
• Fuel system wear
  The mechanical injection pump and lift pump can suffer from internal corrosion or diaphragm failure. Replacing the lift pump and cleaning the fuel tank are common fixes.
  
• Electrical gremlins
  Original wiring harnesses become brittle, especially near the starter and alternator. Rewiring with modern connectors and heat-shrink tubing improves reliability.
  
• Cooling system fatigue
  Radiators may clog with debris or corrode internally. Flushing the system and replacing hoses and thermostats helps maintain optimal engine temperature.
  
• Chain case maintenance
  The drive chains require periodic tensioning and oil changes. Neglecting this can lead to premature wear or failure.
  

A technician in Alberta once restored a 743 that had sat idle for 12 years. After replacing the fuel lines, rebuilding the lift cylinders, and rewiring the starter circuit, the machine fired up and returned to work clearing snow.
Upgrades and Retrofits for Modern Use
To improve usability and safety:

• Install LED work lights for better visibility
  
• Replace the seat with a suspension model for operator comfort
  
• Add auxiliary hydraulic quick-connects for attachments
  
• Retrofit a backup alarm and beacon for jobsite compliance
  
• Upgrade tires to foam-filled or solid for puncture resistance
  

Some owners have even added joystick conversion kits, replacing the original hand-foot controls with pilot-style levers for smoother operation.
Parts Availability and Cross-Referencing
Despite its age, the 743 enjoys strong aftermarket support. Key strategies include:

• Using serial number ranges to match engine and hydraulic components
  
• Sourcing parts from Bobcat dealers, salvage yards, and online suppliers
  
• Cross-referencing Kubota engine parts with agricultural and industrial catalogs
  
• Fabricating brackets and bushings when OEM parts are discontinued
  

The V1702 engine shares components with other Kubota applications, making it easier to find filters, injectors, and gaskets.
Preventive Maintenance Schedule
To keep the 743 in top shape:

• Change engine oil every 100 hours
  
• Replace fuel and air filters every 250 hours
  
• Inspect hydraulic fluid and filters every 500 hours
  
• Check chain case oil level monthly
  
• Grease all pivot points weekly
  
• Monitor tire pressure and tread wear regularly
  

Adding a maintenance logbook helps track service intervals and spot recurring issues.
A Story from the Field
In 2020, a small farm in Wisconsin relied on a Bobcat 743 to clean stalls and move feed. One winter morning, the machine refused to start. After checking the glow plugs and fuel delivery, the owner discovered a cracked lift pump diaphragm. A local mechanic replaced the pump with a compatible aftermarket unit, and the loader was back in service by afternoon. The farm later added a block heater to improve cold starts and began storing diesel with anti-gel additives.
Conclusion
The Bobcat 743 remains a testament to mechanical durability and design simplicity. With proper care, thoughtful upgrades, and a bit of ingenuity, these machines continue to serve decades after their release. In the world of compact loaders, the 743 is more than a relic—it’s a reliable partner that proves old iron still has plenty of bite. When the engine hums and the hydraulics respond, the job gets done with confidence and grit.