Bobcat 743 Skid Steer Loader: Troubleshooting Common Issues

[MikePhua]

The Bobcat 743 Skid Steer Loader, produced from the early 1980s through the early 1990s, is renowned for its durability and versatility. Equipped with a Kubota diesel engine, this machine has been a staple in construction and landscaping projects. However, like any aging equipment, it is prone to certain mechanical issues. Below is a comprehensive guide to diagnosing and addressing common problems associated with the Bobcat 743.
1. Hydraulic System Failures
The hydraulic system is crucial for the operation of the Bobcat 743, powering functions such as lifting, steering, and driving. Common issues include:

• Cavitation Noises: A loud growling or whining noise during operation often indicates air in the hydraulic system. This can be caused by low hydraulic fluid levels or leaks in the suction lines. To resolve this, check and top up the hydraulic fluid, and inspect for any visible leaks.
  
• Loss of Steering or Drive Power: If the machine moves forward and backward but struggles with steering, it may be due to a malfunctioning hydraulic pump or a clogged filter. Regular maintenance, including changing the hydraulic filter and ensuring proper fluid levels, can prevent such issues.
  
• Slow or Uneven Lifting: When the bucket raises slowly or unevenly, it could be due to a failing lift cylinder or a problem with the control valve. Inspecting and replacing worn seals or components can restore proper function.
  

2. Engine Stalling and Power Loss
Engine stalling or loss of power is a common complaint among Bobcat 743 owners. Potential causes include:

• Clogged Fuel Filters: Over time, fuel filters can become clogged with debris, restricting fuel flow and causing the engine to stall. Regularly replacing the fuel filter can mitigate this issue.
  
• Air in Fuel Lines: Air pockets in the fuel lines can disrupt fuel delivery, leading to engine stalling. Bleeding the fuel system to remove air can resolve this problem.
  
• Weak Fuel Lift Pump: A failing lift pump may not provide adequate fuel pressure, causing the engine to run poorly or stall. Testing and replacing the lift pump if necessary can restore engine performance.
  

3. Starting Difficulties
Starting issues are prevalent in older Bobcat 743 models. Common causes include:

• Faulty Glow Plugs: Inadequate pre-heating of the engine can make starting difficult, especially in colder temperatures. Testing and replacing faulty glow plugs can improve starting reliability.
  
• Weak Battery or Charging System: A weak battery or failing alternator may not provide sufficient power to start the engine. Checking the battery voltage and ensuring the charging system is functioning correctly can address this issue.
  

4. Electrical System Issues
Electrical problems can affect various functions of the Bobcat 743, including hydraulic operation and starting. Common issues include:

• Blown Fuses or Relays: Electrical components such as fuses and relays can wear out over time, leading to system failures. Regular inspection and replacement of these components can prevent electrical issues.
  
• Corroded Wiring Connections: Corrosion at wiring connections can disrupt electrical signals, causing erratic behavior. Cleaning and securing electrical connections can resolve such problems.
  

5. General Maintenance Tips
To prolong the life of your Bobcat 743 and prevent common issues:

• Regular Fluid Changes: Adhere to the manufacturer's recommended intervals for changing engine oil, hydraulic fluid, and coolant.
  
• Routine Inspections: Regularly inspect hoses, belts, and other components for signs of wear or damage.
  
• Proper Storage: Store the machine in a dry, sheltered location to protect it from the elements.
  

Conclusion
The Bobcat 743 Skid Steer Loader is a reliable and robust machine when properly maintained. By understanding common issues and implementing regular maintenance practices, operators can ensure optimal performance and extend the lifespan of their equipment.