Common Issues with CAT 955 Loader and Troubleshooting Guide

[MikePhua]

The CAT 955 series, a well-known machine in the Caterpillar lineup, is an iconic crawler loader recognized for its durability, power, and versatility. Originally introduced for heavy lifting and material handling in construction, mining, and earth-moving applications, the CAT 955 is often still used today. However, like any heavy machinery, it comes with its set of potential issues, some of which are particularly common in older models. Understanding these common problems and knowing how to troubleshoot them can help ensure your 955 stays operational for years to come.
Overview of the CAT 955 Loader
The CAT 955 crawler loader was one of the first fully integrated track loaders, combining a track-driven system with a loader bucket. It was designed for tough, off-road environments where traditional wheeled machines could struggle. The machine features powerful hydraulic systems, a strong undercarriage, and a well-known reputation for withstanding demanding jobs.
Despite its rugged build, the CAT 955 has been around for several decades, and its age means that regular maintenance and part replacements are essential to keeping it in working order.
Common Problems with the CAT 955
The CAT 955, like many older models, often faces several issues that stem from wear and tear, outdated technology, and difficulty in sourcing replacement parts. Here are the most common problems encountered:
1. Hydraulic System Issues
One of the most frequently reported problems with the CAT 955 is related to its hydraulic system. Since the loader relies heavily on hydraulics for its bucket and lift operation, issues such as leaks, low pressure, and erratic movements can severely affect its performance.

• Symptoms: Slow or inconsistent movement of the loader's boom, bucket, or lift arms; low pressure readings on the hydraulic gauges; visible fluid leaks from hoses or fittings.
  
• Causes: Over time, hydraulic hoses can wear out or develop cracks. Hydraulic pumps, valves, and cylinders may also wear, leading to performance issues. Dirty hydraulic fluid, clogged filters, or incorrect fluid levels can also contribute to system malfunctions.
  

Solution: Inspect the hydraulic hoses, fittings, and seals for leaks. Regularly change the hydraulic fluid and replace the filters. If pressure issues persist, it may be necessary to replace or rebuild hydraulic pumps or cylinders.
2. Engine and Starting Problems
Engine-related issues are also common, particularly with older engines that have been in service for many years. Common symptoms include difficulty starting, low engine performance, or stalling.

• Symptoms: Hard starting, engine misfiring, poor acceleration, or stalling under load.
  
• Causes: These problems can be caused by a variety of issues, including worn-out fuel injectors, fuel pump issues, dirty or clogged air filters, or malfunctioning sensors. Old fuel lines or poor-quality fuel can also contribute to engine performance problems.
  

Solution: Regularly maintain the engine by replacing the air and fuel filters. If the fuel system is the issue, consider checking the fuel lines for leaks or cracks. Inspect the fuel injectors and fuel pump for proper operation. Cleaning or replacing the injectors and ensuring good-quality fuel can also alleviate starting problems.
3. Track and Undercarriage Issues
As a track machine, the CAT 955 relies heavily on its undercarriage and track system. Over time, the tracks can become loose or damaged, and the rollers, sprockets, and idlers can wear out, leading to a decrease in the machine's mobility and efficiency.

• Symptoms: Slipping tracks, uneven wear on tracks, or unusual noise coming from the undercarriage. A noticeable decrease in traction or stability may also occur.
  
• Causes: Tracks may wear down or become misaligned, leading to poor contact with the ground. The sprockets, rollers, or bushings may have suffered wear and tear, affecting the track's movement and overall stability.
  

Solution: Regularly inspect the tracks for signs of wear and tear. If necessary, adjust the track tension to ensure proper alignment. In cases of severe damage, the tracks may need to be replaced, and rollers or sprockets may require repair or replacement.
4. Transmission Issues
Transmission problems are common in older CAT 955 models, especially when the transmission fluid gets contaminated or levels drop. The machine may have difficulty shifting between gears, or it might slip out of gear under load.

• Symptoms: Difficulty shifting gears, slipping gears, or an inability to move the loader effectively.
  
• Causes: Low transmission fluid levels, dirty fluid, worn-out seals, or problems with the transmission control system can contribute to poor performance.
  

Solution: Check the transmission fluid regularly and ensure it is at the correct level. If the fluid is dirty, change it along with the filter. Inspect the transmission for leaks, and replace any worn-out seals. In some cases, the entire transmission system may need to be inspected or overhauled.
5. Electrical and Wiring Problems
Electrical issues can occur in older machines like the CAT 955, especially when wiring becomes corroded or damaged. The electrical system controls various components of the loader, including the engine, lights, and hydraulic systems.

• Symptoms: Inconsistent operation of electrical components, such as the engine failing to start, lights not working, or the hydraulic system malfunctioning.
  
• Causes: Corroded or damaged wiring, faulty fuses, or malfunctioning relays can cause electrical problems. A weak or dead battery may also contribute to power loss in the electrical system.
  

Solution: Inspect the electrical system, looking for loose connections, damaged wires, or corroded terminals. Replace any faulty fuses or relays. Check the battery's charge and condition, and ensure that all connections are clean and secure.
6. Exhaust System Problems
The exhaust system is another component that can cause performance issues if it becomes clogged or damaged. A cracked exhaust manifold, for instance, can lead to engine noise, power loss, and increased emissions.

• Symptoms: Loud engine noise, noticeable power loss, or visible cracks or leaks in the exhaust system.
  
• Causes: Exhaust manifolds are prone to cracking over time, especially if the engine is running too hot or there are issues with the cooling system. A blocked or damaged muffler or exhaust pipe can also cause problems.
  

Solution: Inspect the exhaust manifold and pipes for visible cracks or leaks. If the manifold is cracked, it may need to be replaced. Regular maintenance of the engine cooling system can help prevent overheating and reduce the likelihood of exhaust system damage.
Preventative Maintenance for the CAT 955
Proper maintenance is key to keeping the CAT 955 in top condition. Regularly scheduled maintenance tasks should include:

• Checking and changing hydraulic fluid and filters.
  
• Cleaning or replacing fuel and air filters.
  
• Inspecting the undercarriage and track tension.
  
• Monitoring transmission fluid levels and quality.
  
• Testing and maintaining the electrical system.
  
• Regularly checking the engine for leaks, loose connections, or signs of wear.
  

By sticking to a routine maintenance schedule, many common problems with the CAT 955 can be avoided or minimized.
Conclusion
The CAT 955 crawler loader is a powerful and reliable piece of equipment when properly maintained. While common problems such as hydraulic system malfunctions, engine issues, track wear, and transmission failures can arise, understanding the causes and implementing timely solutions can significantly extend the machine’s lifespan. Routine inspections and preventive measures are key to keeping the CAT 955 running smoothly, ensuring that it continues to perform in demanding conditions for years to come.