The Adventures of Operating the 955K: Troubleshooting and Solutions

[MikePhua]

The Caterpillar 955K is a legendary track loader, known for its versatility and durability in construction, landscaping, and material handling. As a staple on many job sites, it is beloved by operators for its power and ease of use. However, like all heavy machinery, the 955K can develop quirks and issues over time. This guide takes a deeper dive into some of the challenges faced by one operator and the journey of troubleshooting and repairing their 955K, also known as a "rattletrap," offering solutions along the way.
Introduction to the 955K Track Loader
The 955K, introduced by Caterpillar in the 1960s, is a machine that has endured the test of time. It is recognized for its reliable engine and powerful hydraulics, ideal for tasks that require heavy lifting, digging, and loading. Operators appreciate its rugged design, which allows it to work efficiently on tough terrains. Despite its robust build, the 955K, like any machine, is not immune to mechanical issues.
Key features of the 955K:

1. Powerful Engine: Typically equipped with a 4-cylinder diesel engine, it provides the necessary torque for challenging tasks.
   
2. Hydraulic System: The hydraulics control the loader’s boom, bucket, and attachments, offering smooth operation.
   
3. Undercarriage: The tracks allow the 955K to handle rough and uneven surfaces, making it a preferred machine for digging and loading.
   
4. Operator's Cabin: The machine's cockpit offers basic controls and visibility, though it's not as modern as more recent machines.
   

However, with age comes wear, and the 955K can face several issues that need attention from both new and seasoned operators.
Common Problems with the 955K: A Rattletrap Story
One of the more memorable experiences of operating a 955K is dealing with its notorious "rattletrap" status. While this term is used affectionately by some operators, it also reflects the reality of a machine that may require frequent maintenance and repairs due to its age.
Here are the main problems faced by one operator and the steps taken to address them:

1. Hydraulic System Noise and Loss of Power
   Over time, the hydraulic system on the 955K can develop issues such as a loud rattle or a noticeable loss of lifting power. These problems often stem from either a lack of hydraulic fluid, contamination, or wear in key components.
   Symptoms:
   • Abnormal rattle noise coming from the hydraulic system
     
   • Slow or jerky operation of the loader’s bucket and boom
     
   • Reduced lifting capacity
     
   Troubleshooting Steps:
   • Check Fluid Levels: Hydraulic fluid is essential for smooth operation. If the fluid level is low, this could cause noise and power loss. Refill with the recommended hydraulic oil and check for leaks.
     
   • Inspect Filters: A clogged filter can restrict fluid flow, leading to performance issues. Replace the hydraulic filter to ensure optimal function.
     
   • Examine Hydraulic Hoses and Cylinders: Check for any damage or leaks in the hoses and cylinders, as these can cause a drop in hydraulic pressure. Replace any faulty components.
     
   • Bleed the System: Air trapped in the hydraulic lines can lead to poor performance. Bleeding the system to release any air may resolve the issue.
     
2. Engine Stalling or Difficulty Starting
   Engine issues in the 955K can manifest as stalling or difficulty starting, often due to problems with the fuel system, ignition, or battery.
   Symptoms:
   • Engine cranks but fails to start
     
   • Rough idling or frequent stalling during operation
     
   • Loss of power or performance while the machine is running
     
   Troubleshooting Steps:
   • Inspect Fuel System: Start by checking the fuel filters and fuel lines for blockages. Clogged filters are a common cause of engine stalling. Replace any dirty filters and check the fuel lines for any signs of wear.
     
   • Check the Battery: If the battery is weak or discharged, it may cause difficulty starting. Test the battery voltage and replace it if necessary.
     
   • Examine the Starter Motor: A faulty starter motor can cause the engine to fail to start. Test the starter motor and replace it if it shows signs of wear.
     
   • Inspect the Glow Plugs: If the 955K has trouble starting in cold weather, the glow plugs may not be functioning properly. Replace any defective glow plugs to ensure smooth starting.
     
3. Track Wear and Undercarriage Maintenance
   As with any track loader, the 955K’s undercarriage requires regular maintenance. The tracks and rollers can wear out, especially when working on rough or uneven terrain.
   Symptoms:
   • Uneven track wear or loose tracks
     
   • Difficulty moving or steering the loader
     
   • Excessive wear on the rollers or sprockets
     
   Troubleshooting Steps:
   • Check Track Tension: Tracks that are either too tight or too loose can cause uneven wear. Adjust the track tension to the manufacturer’s specifications.
     
   • Inspect the Tracks: Look for signs of wear such as cracks, broken links, or missing teeth. Replace damaged sections to maintain stability.
     
   • Examine the Rollers and Sprockets: Worn-out rollers and sprockets can cause problems with the tracks. Inspect these components regularly and replace any that show excessive wear.
     
   • Lubricate the Undercarriage: Lubricating the undercarriage helps to prevent premature wear on moving parts. Use the recommended lubricants and apply them regularly to keep the system running smoothly.
     
4. Transmission Issues and Sluggish Movement
   Sluggish movement or difficulty shifting gears can be a sign of transmission issues in the 955K, especially when the fluid becomes contaminated or low.
   Symptoms:
   • Slow or erratic movement when shifting gears
     
   • Unusual noises from the transmission
     
   • Difficulty accelerating or maintaining speed
     
   Troubleshooting Steps:
   • Check Transmission Fluid Levels: Low or contaminated fluid can cause shifting problems. Ensure the fluid is at the correct level and replace it if it appears dirty or contaminated.
     
   • Inspect the Transmission Filters: A clogged transmission filter can restrict fluid flow, affecting performance. Replace the filter regularly to maintain proper function.
     
   • Flush the Transmission: If the fluid is dirty or contaminated, it may be necessary to flush the entire transmission system to remove debris and buildup.
     
   • Check for Leaks: Leaks in the transmission system can lead to a loss of pressure, affecting performance. Inspect the seals, gaskets, and hoses for leaks and replace any damaged parts.
     
5. Excessive Vibration and Rattling
   An often-reported issue with the 955K is excessive vibration and rattling sounds during operation, particularly in older machines. This can be caused by worn engine mounts, loose parts, or damage to the undercarriage.
   Symptoms:
   • Unusual rattling or vibrating sounds
     
   • Loose or unstable components during operation
     
   • Poor overall stability and control
     
   Troubleshooting Steps:
   • Check Engine Mounts: Worn or broken engine mounts can cause excessive vibrations. Inspect the mounts and replace any that are damaged or loose.
     
   • Inspect Loose Parts: Over time, parts may become loose due to wear or vibration. Tighten bolts and inspect all components to ensure they are secure.
     
   • Examine the Undercarriage: Damaged tracks, rollers, or sprockets can also cause instability and rattling. Inspect the undercarriage and replace any damaged parts to restore smooth operation.
     

Preventative Maintenance Tips for the 955K
To avoid many of the problems discussed above, regular preventative maintenance is essential. Here are some key maintenance practices to keep the 955K running smoothly:

1. Change Fluids Regularly: Engine oil, hydraulic fluid, and transmission fluid should be changed at the intervals recommended by the manufacturer to ensure optimal performance.
   
2. Inspect and Replace Filters: Regularly inspect and replace air, fuel, and hydraulic filters to prevent blockages and ensure efficient operation.
   
3. Check for Leaks: Periodically inspect hoses, seals, and gaskets for leaks. Fixing leaks early can prevent more significant issues later on.
   
4. Lubricate Moving Parts: The undercarriage, arms, and bucket should be lubricated regularly to prevent premature wear.
   
5. Monitor Track Condition: Tracks should be regularly checked for signs of wear, and the track tension should be adjusted as necessary.
   

Conclusion
Operating a Caterpillar 955K can be an enjoyable experience when the machine is in top working condition, but it does require regular maintenance and attention to keep it running smoothly. From troubleshooting hydraulic issues to addressing engine problems and maintaining the undercarriage, keeping the "rattletrap" in good shape ensures that it continues to perform reliably on the job site. Regular inspections, proper lubrication, and fluid changes can go a long way in preventing common issues and extending the life of this iconic piece of equipment. With the right care, the 955K will remain a powerful and dependable workhorse for years to come.