Deere 120C Excavator: Features, Troubleshooting, and Maintenance Tips

[MikePhua]

The Deere 120C is a part of John Deere's 120-series excavators and is designed for light to medium-duty construction and excavation tasks. Known for its compact design, powerful hydraulics, and excellent operator comfort, the 120C has earned its reputation as a reliable and efficient machine in the industry. This article will provide an in-depth look at the features of the Deere 120C, common issues that operators may face, and best practices for maintaining the machine to ensure optimal performance.
Key Features of the Deere 120C Excavator

1. Engine Performance and Efficiency
   The Deere 120C is powered by a Tier 3, 4.5L engine that delivers around 85 horsepower (63 kW). This engine provides ample power for digging, lifting, and operating attachments while maintaining fuel efficiency. John Deere's engines are known for their durability and reliability, and the 120C is no exception. The engine’s design also meets stringent emissions regulations, making it suitable for environmentally-conscious projects.
   
2. Hydraulic System
   The hydraulic system of the Deere 120C is one of its standout features. It uses a load-sensing hydraulic system that adjusts pressure based on the machine's workload, ensuring smooth operation. This system provides improved fuel efficiency and better control over the boom, arm, and bucket. Operators can expect precise movements, even when dealing with heavy loads or fine-tuning for intricate tasks.
   
3. Compact Design with Excellent Reach
   One of the key benefits of the Deere 120C is its compact size, making it ideal for working in confined spaces, such as urban construction sites or areas with limited accessibility. Despite its small size, the 120C offers a maximum digging depth of 14.5 feet (4.42 meters) and a reach of 22 feet (6.71 meters), which allows it to handle most digging tasks with ease.
   
4. Operator Comfort and Control
   John Deere places a strong emphasis on operator comfort, and the 120C is no different. The cab is spacious and features a high-back seat with adjustable settings to reduce fatigue during long shifts. The controls are intuitive, with joystick controls for smoother movements and a display panel that provides real-time information on the machine's performance. The climate-controlled cab also ensures that operators remain comfortable in various working conditions.
   
5. Heavy-Duty Undercarriage and Durability
   The undercarriage of the Deere 120C is designed to handle rough terrains and demanding work environments. The tracks are built to last, and the high flotation undercarriage ensures better stability and traction, even on softer or muddy surfaces. The machine's structure is robust, designed to withstand the rigors of daily construction work.
   

Common Issues with the Deere 120C Excavator and How to Troubleshoot Them
Like any heavy equipment, the Deere 120C may experience performance issues. Here are some of the most common problems that operators may encounter, along with solutions for each:
1. Hydraulic System Failure
One of the most common issues with excavators is hydraulic system failure, which can manifest in various ways such as weak boom movements, slow bucket actions, or the complete inability to operate certain functions.
Symptoms:

• Slow or jerky hydraulic movement.
  
• Inability to lift or move heavy loads.
  
• Unresponsive joystick controls.
  

Possible Causes:

• Low hydraulic fluid: Insufficient fluid in the hydraulic system can lead to poor performance or total failure of hydraulic functions.
  
• Clogged filters: Over time, dirt and debris can clog hydraulic filters, reducing fluid flow.
  
• Leaking hydraulic lines: Damaged or worn-out hoses and seals may lead to fluid leaks, which can reduce the effectiveness of the hydraulic system.
  

Solutions:

• Check Hydraulic Fluid: Always ensure the hydraulic fluid is at the correct level. If it is low, refill it with the appropriate fluid.
  
• Change Filters: Replace hydraulic filters as part of your routine maintenance schedule to prevent blockages.
  
• Inspect for Leaks: Check hydraulic lines and connections for leaks. Replace any damaged hoses or seals immediately.
  

2. Engine Overheating
Overheating is a critical issue that can cause long-term damage to the engine and other components of the excavator.
Symptoms:

• Engine temperature gauge reading in the red zone.
  
• Loss of power or performance while operating.
  
• Unusual engine sounds or vibrations.
  

Possible Causes:

• Low coolant levels: A drop in coolant levels can cause the engine to overheat.
  
• Clogged radiator: Dust and debris can block the radiator, preventing proper cooling.
  
• Faulty thermostat: A malfunctioning thermostat can fail to regulate engine temperature effectively.
  

Solutions:

• Check Coolant Levels: Ensure the coolant is at the proper level and refill if necessary.
  
• Clean the Radiator: Periodically clean the radiator to remove any debris that may block airflow.
  
• Replace the Thermostat: If the thermostat is malfunctioning, replace it to maintain proper engine temperature regulation.
  

3. Track Issues
The undercarriage is an essential part of any excavator, and if there are issues with the tracks, it can affect the machine's mobility and stability.
Symptoms:

• Uneven track wear.
  
• Track slippage or loss of traction.
  
• Unusual noises from the undercarriage.
  

Possible Causes:

• Worn-out tracks: Over time, tracks can wear down, leading to poor performance and potential breakdowns.
  
• Improper track tension: Tracks that are too loose or too tight can cause uneven wear or damage.
  
• Damaged sprockets or rollers: Sprockets or rollers that are worn out or damaged can lead to poor track performance.
  

Solutions:

• Check Track Tension: Ensure the tracks are properly tensioned, neither too loose nor too tight. Adjust them as needed.
  
• Replace Worn Tracks: If the tracks are excessively worn, replace them to avoid further damage.
  
• Inspect Sprockets and Rollers: Check the sprockets and rollers for damage. Replace any worn-out components immediately.
  

4. Starting Issues
Sometimes, the Deere 120C may fail to start or exhibit delayed start behavior. This can be caused by a number of factors, particularly related to the electrical system.
Symptoms:

• Engine cranks but does not start.
  
• Delayed engine start after turning the key.
  
• No power to the starter motor.
  

Possible Causes:

• Weak or dead battery: A weak or discharged battery is a common cause of starting issues.
  
• Faulty starter motor: A malfunctioning starter motor can prevent the engine from starting.
  
• Loose or corroded battery terminals: Loose or corroded connections can prevent the proper flow of power to the engine.
  

Solutions:

• Test the Battery: Check the battery's charge and replace it if necessary.
  
• Inspect the Starter Motor: If the battery is in good condition but the engine still won't start, inspect the starter motor for signs of failure.
  
• Clean Battery Terminals: Ensure the battery terminals are clean and tightly connected to avoid power issues.
  

Maintenance Tips for the Deere 120C Excavator
To keep your Deere 120C running smoothly, regular maintenance is essential. Here are some key maintenance tips:

1. Check Fluids Regularly: Always monitor the fluid levels for the engine, hydraulics, and coolant. Maintaining the correct fluid levels is critical for performance and longevity.
   
2. Clean or Replace Air Filters: Clean or replace the air filters regularly to ensure the engine gets clean air. Clogged air filters can reduce engine efficiency and increase fuel consumption.
   
3. Inspect and Tighten Bolts: Periodically inspect the machine for loose bolts or fasteners, especially in high-stress areas like the undercarriage, engine mounts, and hydraulic components.
   
4. Grease Moving Parts: Regularly grease moving components such as the boom, arm, and bucket. This helps reduce wear and ensures smooth operation.
   
5. Track Maintenance: Keep an eye on the tracks and undercarriage. Regularly check for wear, and keep the tracks clean and properly tensioned to avoid unnecessary strain on the components.
   
6. Routine Hydraulic System Checks: Perform regular checks on the hydraulic system, including the pumps, valves, and hoses. A well-maintained hydraulic system ensures consistent performance and reduces the risk of costly repairs.
   

Conclusion
The Deere 120C is a powerful and reliable machine designed for a wide range of construction and excavation tasks. Its efficient hydraulic system, compact design, and operator-friendly features make it a versatile and valuable asset on any job site. By staying on top of regular maintenance and addressing common issues such as hydraulic failure, track problems, and engine overheating, operators can ensure the 120C performs optimally and remains a productive machine for years to come.