Troubleshooting the CAT 955H: Common Issues and Solutions

[MikePhua]

The Caterpillar 955H, a versatile and durable crawler loader, is a machine known for its rugged performance in construction, mining, and agricultural applications. Manufactured in the mid-20th century, this model remains a critical tool for heavy-duty tasks, especially when it comes to moving materials in harsh conditions. However, like any piece of heavy machinery, the CAT 955H can experience mechanical issues over time. Understanding common problems and how to troubleshoot them can help operators and maintenance crews keep this iconic machine running smoothly.
CAT 955H Overview
The CAT 955H was introduced in the 1960s as part of Caterpillar's long-running line of track loaders. These machines were designed to move large quantities of material efficiently, whether it be soil, rocks, or debris. Known for its power, the 955H has a high torque-to-weight ratio that allows it to handle challenging terrains with ease. It's equipped with a powerful diesel engine, robust hydraulics, and a variety of attachments, making it an invaluable piece of equipment in multiple industries.
Common Issues with the CAT 955H
While the 955H is built to last, certain issues tend to crop up as the machine ages. Some of the most frequent problems faced by operators and technicians include:

1. Hydraulic System Failures
   One of the most common problems with the CAT 955H is issues with its hydraulic system. Given that the loader relies heavily on hydraulics for its various functions, any malfunction in this system can lead to major disruptions.
   • Slow Hydraulic Response: If the loader’s hydraulic functions respond slowly, it may indicate low fluid levels, air in the system, or worn-out components like the hydraulic pump or valves.
     
   • Leaks: Over time, hydraulic lines, seals, or fittings can degrade, leading to oil leaks. This reduces hydraulic pressure and impacts the machine’s ability to perform tasks efficiently.
     
   Solution: Regular inspection of the hydraulic system, checking fluid levels, and replacing any worn-out seals or hoses can help prevent significant hydraulic issues. Additionally, cleaning the hydraulic filter and replacing it as needed can ensure smoother operation.
   
2. Engine Performance Problems
   The CAT 955H is powered by a diesel engine, which can face issues such as poor starting, lack of power, or overheating.
   • Hard Starting: This could be caused by faulty glow plugs, a weak battery, or fuel delivery problems. In some cases, the fuel injectors may be clogged or malfunctioning.
     
   • Loss of Power: If the engine struggles to maintain power, it could be due to an issue with the fuel pump, air filter, or exhaust system.
     
   Solution: Perform routine maintenance on the engine by checking the fuel system for any clogs or restrictions. Cleaning or replacing the air filter and ensuring the battery is properly charged can also prevent starting issues.
   
3. Undercarriage Wear
   The undercarriage of the CAT 955H is critical for its mobility and stability. Over time, tracks, rollers, and sprockets can wear out due to heavy use, causing the loader to move unevenly or become less effective on rough terrain.
   • Track Wear and Tension Issues: Uneven track wear or improper tension can lead to poor traction, affecting the machine’s ability to move material efficiently.
     
   • Sprocket Wear: Worn sprockets can cause the tracks to slip or derail, creating costly repairs and downtime.
     
   Solution: Regularly inspect the undercarriage, check track tension, and replace any worn-out components. Maintaining proper lubrication on the tracks and rollers can extend the lifespan of the undercarriage parts.
   
4. Transmission and Drive Train Problems
   The CAT 955H’s transmission is responsible for delivering power from the engine to the tracks. Over time, the transmission can suffer from issues such as slipping, overheating, or irregular shifting.
   • Slipping Gears: If the loader’s transmission is slipping, it could be due to low fluid levels, worn clutch plates, or a malfunctioning valve.
     
   • Overheating: Overheating can occur if the transmission fluid is old or dirty, or if there are issues with the cooling system.
     
   Solution: Regularly check the transmission fluid levels and replace the fluid as recommended by the manufacturer. Also, inspect the cooling system to ensure it’s functioning correctly and the radiator isn’t clogged.
   
5. Steering and Control Failures
   The steering system in the CAT 955H allows the operator to guide the loader with precision. Failures in the steering can lead to unresponsive movements, which can be dangerous in certain work environments.
   • Stiff or Unresponsive Steering: This could be due to low hydraulic fluid levels, worn steering components, or issues with the steering motor.
     
   • Uneven Steering: If one track is turning more slowly than the other, it could be related to a faulty valve or a problem with the hydraulic circuit.
     
   Solution: Regularly check the steering hydraulic fluid and ensure the system is properly bled to remove any air. Worn-out steering components should be replaced to maintain smooth operation.
   
6. Electrical System Malfunctions
   As with any older machine, the electrical system in the CAT 955H can experience problems, particularly with wiring, connectors, and sensors.
   • Faulty Alternator or Charging Issues: If the alternator isn’t charging properly, the battery may not have enough power to start the engine.
     
   • Broken Wires or Fuses: Over time, wires can fray or become disconnected, causing electrical malfunctions that prevent the machine from operating as it should.
     
   Solution: Inspect the wiring and fuses for any damage, and replace them as needed. If the alternator is faulty, it should be tested and replaced.
   

Routine Maintenance Tips
To keep the CAT 955H running efficiently and reduce the likelihood of these common issues, it’s important to follow a comprehensive maintenance schedule. Some essential maintenance tasks include:

1. Engine Oil and Filter Changes: Change the engine oil and replace the oil filter at regular intervals to ensure optimal engine performance.
   
2. Hydraulic Fluid and Filter: Regularly check the hydraulic fluid levels and change the hydraulic filter to keep the system clean and efficient.
   
3. Undercarriage Inspection: Inspect the tracks, rollers, and sprockets frequently for wear, and replace any damaged components promptly.
   
4. Transmission Fluid Checks: Maintain proper transmission fluid levels and replace the fluid when it becomes contaminated or degraded.
   
5. Battery and Electrical Checks: Inspect the battery, wiring, and electrical components regularly to avoid starting issues and prevent electrical malfunctions.
   

Conclusion
The CAT 955H, while a robust machine, requires proper maintenance and troubleshooting to continue performing at its best. By addressing common issues such as hydraulic failures, engine problems, undercarriage wear, transmission issues, and electrical malfunctions, operators can ensure the machine’s longevity and efficiency. Routine inspections and following the manufacturer’s maintenance guidelines are key to keeping the CAT 955H running smoothly, ensuring its continued success in heavy-duty operations for many years to come.