Understanding the Caterpillar 955L Track Loader: Key Insights and Common Troubleshooting

[MikePhua]

The Caterpillar 955L track loader, produced around the 1980s, remains a significant piece of machinery in the heavy equipment world. This loader is known for its durability and power, providing exceptional performance on various construction, mining, and excavation projects. Despite its age, the 955L continues to be used in many industrial applications, and understanding its key components and troubleshooting common issues is vital for keeping it running efficiently.
This article explores the features of the Caterpillar 955L, common problems that operators may encounter, and solutions to those issues. We will dive into the importance of the engine, transmission, and undercarriage components, as well as maintenance tips to prolong the life of this classic machine.
Overview of the Caterpillar 955L
The Caterpillar 955L is a track loader designed for versatility and power. It was built to perform a wide range of tasks, including material handling, grading, and digging. As part of the “L” series, it came equipped with a powerful engine and a hydraulic system capable of delivering smooth and efficient operations in challenging conditions.
Engine and Powertrain
The 955L is powered by a Caterpillar 3304 engine, which is renowned for its reliability and fuel efficiency. This engine is a four-cylinder diesel that produces approximately 75 horsepower, making it suitable for tough worksite conditions. The engine is connected to a direct drive transmission system that provides smooth shifting, ideal for tasks like pushing, lifting, and digging.
The hydraulic system of the 955L features a closed-center, load-sensing design, providing the operator with precise control over attachments such as buckets, rippers, and other implements. These hydraulic systems are key to maintaining the loader’s versatility and efficiency in operations.
Common Issues with the Caterpillar 955L
While the 955L is a robust machine, operators may face a few recurring issues due to its age. Here’s a breakdown of the common problems and their solutions:
1. Hydraulic System Failures
The hydraulic system of the 955L is essential for powering the loader’s lifting and digging capabilities. However, over time, issues such as leaks, insufficient fluid, or pump malfunctions can occur.

• Cause: Hydraulic fluid leaks are often the result of worn seals, damaged hoses, or corrosion in the system. In addition, an aging hydraulic pump can lose its ability to generate the necessary pressure.
  
• Symptoms: Slow or unresponsive lifting and tilting movements, erratic or uneven bucket operation, and fluid leakage around the hydraulic components.
  
• Solution: Regular inspection of hydraulic lines, hoses, and seals is crucial. If a leak is detected, replace the damaged components immediately. Check the hydraulic pump’s performance and replace it if necessary. Be sure to maintain the correct level of clean hydraulic fluid to avoid system strain.
  

2. Engine Performance Issues
Given that the 955L is powered by the Caterpillar 3304 engine, which is highly regarded for its durability, issues with the engine typically stem from poor maintenance or neglect.

• Cause: Common engine-related problems include clogged fuel filters, dirty air filters, and issues with the fuel injection system. Overheating can also occur if the cooling system is not properly maintained.
  
• Symptoms: Difficulty starting the engine, engine misfires, low power, and overheating during operation.
  
• Solution: Perform regular maintenance on the fuel and air filtration systems. Ensure that fuel filters are changed at the recommended intervals and that air filters are cleaned or replaced when clogged. Monitor the engine temperature and check the radiator and coolant system for leaks. If overheating continues, investigate the water pump or thermostat for failure.
  

3. Transmission and Final Drive Issues
The transmission and final drive are critical components for moving the loader efficiently across the job site. Failures in these areas can lead to significant downtime and expensive repairs.

• Cause: Worn or damaged transmission gears, low transmission fluid, or a malfunctioning final drive can cause issues in movement.
  
• Symptoms: Difficulty shifting gears, jerking or slipping while moving, or complete loss of power to the tracks.
  
• Solution: Inspect the transmission fluid levels regularly and ensure the fluid is clean and free of contaminants. If shifting issues persist, check the transmission for worn components. Also, inspect the final drive for wear or leaks and replace any faulty parts.
  

4. Undercarriage and Track Problems
As with any tracked loader, the undercarriage components, including the tracks, rollers, and sprockets, experience wear over time. The 955L’s performance can suffer significantly if the undercarriage is not properly maintained.

• Cause: Worn tracks or damaged rollers, sprockets, and track links can result from prolonged use or lack of proper lubrication and maintenance.
  
• Symptoms: Noisy operation, reduced traction, difficulty moving, and track slippage.
  
• Solution: Regularly check the undercarriage components for signs of wear. Tracks should be replaced when they show signs of excessive wear. Rollers and sprockets should be inspected for damage or cracking. Lubricate components regularly to minimize friction and extend the life of the tracks.
  

Transmission and Final Drive Troubleshooting
The transmission and final drive are complex systems, and diagnosing problems in these areas requires methodical troubleshooting. Here's a step-by-step guide to handling these issues:

1. Check Transmission Fluid Levels: Low fluid levels are a common cause of transmission problems. If the fluid is low, top it off with the recommended type of oil.
   
2. Inspect for Leaks: A common problem with the transmission and final drive is leakage. Check the seals and gaskets for any signs of leakage. If a leak is detected, replace the faulty seal or gasket.
   
3. Test the Shift Mechanism: If the loader is not shifting properly, it could be due to a malfunctioning shift solenoid or valve. Check the solenoids and valves for proper function.
   
4. Examine the Final Drive: The final drive is crucial for converting power from the engine into track movement. Check the sprockets, rollers, and track for signs of wear and replace any components that are worn out.
   

Regular Maintenance and Tips
For optimal performance, the Caterpillar 955L requires routine maintenance to keep it running smoothly. Here are some key tips for operators and fleet managers:

• Track Tension: Keep track tension at the proper level to avoid excessive wear on the track components. Too tight a track can cause the rollers to wear out quickly, while too loose a track can result in slipping or track derailment.
  
• Fluid Changes: Regularly change the engine oil, transmission fluid, and hydraulic fluid as per the manufacturer’s recommendations. This will ensure the components are properly lubricated and function as intended.
  
• Cleaning: Clean the engine and undercarriage frequently to prevent dirt and debris buildup. Accumulated dirt can block air filters, radiators, and hydraulic lines, leading to overheating and reduced performance.
  
• Inspection: Regularly inspect the machine for signs of wear, especially the undercarriage, hydraulic system, and engine. Catching issues early can prevent costly repairs down the line.
  

Final Thoughts
The Caterpillar 955L track loader remains a reliable piece of equipment for many construction professionals, even though it was produced over 40 years ago. Proper care, regular maintenance, and prompt troubleshooting can extend its service life and ensure smooth operations on the job site. By understanding its core components and the most common issues, operators can effectively troubleshoot and repair any problems that arise, keeping the 955L running for years to come.
The 955L's legacy as a workhorse in tough environments speaks to its enduring design and durability, a testament to the craftsmanship of Caterpillar machinery.