CAT 955K Series 85J: A Detailed Analysis of Features, Common Issues, and Maintenance

[MikePhua]

The Caterpillar 955K, specifically the Series 85J, is part of the iconic line of track loaders produced by Caterpillar, known for their durability, versatility, and robust performance. These machines have been a vital part of the construction, mining, and industrial sectors for decades. The 955K is celebrated for its ability to perform multiple tasks such as pushing, lifting, and digging, all while maintaining excellent mobility in rough terrain. However, like any heavy machinery, it is important for operators and owners to understand the key features, potential issues, and maintenance practices necessary to keep the CAT 955K Series 85J running at its peak. This article delves into the specifications, common problems, and best practices for ensuring the longevity and performance of this legendary machine.
CAT 955K Series 85J Features
The CAT 955K Series 85J was designed to provide maximum productivity and flexibility on the job site. It has several features that set it apart from its competitors in the track loader market. Below are some of the standout specifications and features:

1. Engine Power and Performance:
   The 955K is powered by a 4.4-liter, six-cylinder diesel engine, which provides around 90 horsepower. This engine is designed to deliver enough power to perform heavy-duty operations, such as lifting and pushing, while also being fuel-efficient for long hours of operation.
   
2. Hydraulic System:
   The hydraulic system in the 955K is capable of providing the necessary lifting force and movement precision for the machine’s various attachments, such as buckets, forks, and other implements. The hydraulic pump provides consistent flow, helping to maintain performance even under heavy loads.
   
3. Track Design and Mobility:
   With its wide tracks, the CAT 955K Series 85J offers excellent flotation, allowing the machine to work in soft or muddy conditions without sinking. The tracks also ensure smooth operation on uneven terrain, making it a valuable machine in challenging environments such as construction sites and mines.
   
4. Versatility:
   The 955K is designed to handle a variety of tasks, from lifting and digging to material handling and grading. Its bucket capacity is large enough to move substantial amounts of material, and the machine can be easily fitted with various attachments to suit different tasks.
   
5. Operator Comfort and Visibility:
   The cab is designed with comfort in mind, offering operators good visibility of the work area and easy access to all the controls. This allows for better control of the machine during operations, minimizing the risk of accidents and improving overall productivity.
   
6. Durability and Construction:
   The 955K Series 85J is built with high-quality materials, making it extremely durable in harsh working conditions. Its rugged construction ensures that it can withstand the demands of continuous heavy work in construction, mining, and demolition sites.
   

Common Issues with the CAT 955K Series 85J
While the 955K is a robust and reliable machine, it is not without its potential issues. Understanding these common problems can help operators and owners prevent costly downtime and repairs. Here are some of the more frequently encountered issues:

1. Hydraulic System Failures
   Hydraulic issues are among the most common problems faced by the CAT 955K. These issues often arise from poor maintenance or contamination of the hydraulic fluid. Symptoms of hydraulic system failures can include slow or erratic movement of the machine's arms, bucket, or other attachments.
   Possible Causes:
   • Low hydraulic fluid levels or contamination
     
   • Worn or damaged hydraulic hoses
     
   • Malfunctioning hydraulic pump or valves
     
   • Air in the hydraulic system
     
   Solutions:
   • Regularly check hydraulic fluid levels and replace the fluid if it appears dirty or contaminated.
     
   • Inspect hydraulic hoses for leaks and replace worn or cracked hoses.
     
   • Ensure that the hydraulic pump and valves are in good working order.
     
   • Bleed the system to remove air if necessary.
     
2. Transmission Issues
   The transmission system in the 955K is responsible for transferring power from the engine to the tracks. When there are problems with the transmission, it can lead to a loss of power or difficulty moving the machine.
   Possible Causes:
   • Low transmission fluid levels
     
   • Worn-out transmission components
     
   • Contaminated fluid causing blockage or slippage
     
   Solutions:
   • Regularly check and maintain the proper level of transmission fluid.
     
   • Inspect the transmission for worn components and replace them if needed.
     
   • Replace contaminated fluid and ensure the transmission is regularly serviced.
     
3. Track and Undercarriage Problems
   Track loaders like the 955K rely on their undercarriage for stability and mobility. Problems with the tracks or undercarriage components can cause the machine to become less mobile or even completely immobilized.
   Possible Causes:
   • Worn or damaged tracks
     
   • Loose or damaged rollers and idlers
     
   • Misalignment of track components
     
   Solutions:
   • Inspect the tracks regularly for wear and damage. Replace worn-out tracks to avoid potential failure during operation.
     
   • Check the rollers, idlers, and other undercarriage components for damage and ensure they are properly aligned.
     
   • Regularly lubricate moving parts to prevent excessive wear.
     
4. Engine Overheating
   Engine overheating can occur when the cooling system is compromised. This can lead to damage to the engine and result in costly repairs if not addressed promptly.
   Possible Causes:
   • Low coolant levels
     
   • Blocked or damaged radiator
     
   • Faulty thermostat or water pump
     
   Solutions:
   • Regularly check coolant levels and top up when necessary.
     
   • Inspect the radiator for debris or blockages and clean it if needed.
     
   • Replace any faulty thermostat or water pump to maintain the engine's cooling efficiency.
     
5. Electrical System Failures
   Electrical problems, such as issues with the alternator, wiring, or battery, can cause the machine to lose power or fail to start altogether.
   Possible Causes:
   • Worn or corroded battery connections
     
   • Faulty alternator or electrical wiring
     
   • Blown fuses or relays
     
   Solutions:
   • Regularly check the battery and clean any corrosion from the terminals.
     
   • Inspect the alternator and electrical wiring for any signs of wear or damage.
     
   • Replace any blown fuses or faulty relays to ensure proper electrical function.
     

Maintenance Tips for the CAT 955K Series 85J
Proper maintenance is key to extending the lifespan of the CAT 955K Series 85J and avoiding the issues mentioned above. Here are some essential maintenance practices:

1. Routine Fluid Checks:
   Regularly check and replace hydraulic fluid, engine oil, and transmission fluid. This will help ensure smooth operation and prevent system failures.
   
2. Track and Undercarriage Maintenance:
   Perform routine inspections of the tracks, rollers, and undercarriage components. Keeping the undercarriage well-maintained is crucial for maintaining stability and mobility.
   
3. Cooling System Maintenance:
   Check the coolant levels and inspect the radiator for any blockages. Clean or replace the radiator as needed to avoid engine overheating.
   
4. Electrical System Inspections:
   Periodically inspect the electrical system for any issues, including the battery, alternator, and wiring. Keeping the electrical system in good condition ensures reliable operation.
   
5. Scheduled Servicing:
   Follow the manufacturer’s recommended maintenance schedule for servicing the machine. This includes checking components like the hydraulic system, transmission, and engine, as well as replacing worn-out parts before they fail.
   

Real-World Example: The Durability of the CAT 955K in Mining Operations
The CAT 955K has been widely used in mining operations due to its rugged construction and powerful performance. A mining company in Alaska, for example, relied on a fleet of 955K loaders to handle the harsh conditions of the site, including rough terrain and freezing temperatures. The operators praised the 955K for its ability to handle heavy loads without issue and its relatively low maintenance needs, provided that routine checks were performed regularly.
Conclusion
The CAT 955K Series 85J is a dependable and versatile track loader that can handle a wide range of tasks in construction, mining, and industrial applications. While it is built for durability, regular maintenance and attention to common issues such as hydraulic failures, transmission problems, and overheating are essential for maximizing its lifespan and performance. By adhering to a proactive maintenance schedule and addressing any issues promptly, owners and operators can ensure that their CAT 955K continues to deliver outstanding performance for years to come.