A Comprehensive Guide to the Kobelco 907 Excavator

[MikePhua]

The Kobelco 907 is a compact yet powerful hydraulic excavator that has gained popularity for its excellent performance in tight spaces. Commonly used in urban construction, utility work, and landscaping, the 907 offers a good balance of size and power, making it an ideal choice for many operators. However, like all complex machinery, the Kobelco 907 can encounter issues over time. This article explores the features, common problems, maintenance tips, and troubleshooting advice for this machine.
Overview of the Kobelco 907 Excavator
The Kobelco 907 is part of the Kobelco mini-excavator lineup. It is known for its exceptional hydraulic performance and efficiency, which makes it suitable for a range of tasks including digging, trenching, and lifting. With a relatively small operating weight, it can easily navigate confined work areas while still providing substantial lifting power.
Key Features:

1. Operating Weight: The Kobelco 907 typically weighs around 9 tons, making it compact enough for city construction projects but still capable of handling medium-sized digging jobs.
   
2. Engine Power: Equipped with a 55-70 horsepower engine, the 907 delivers solid performance with a good balance of fuel efficiency and power.
   
3. Hydraulic System: The machine uses advanced hydraulic technology to maximize lifting power and digging capabilities.
   
4. Boom and Arm: The 907's arm and boom provide a high digging depth and reach, making it versatile in various operations.
   
5. Cab Comfort: The operator's cab is designed for comfort, with a spacious layout, easy-to-reach controls, and good visibility, helping reduce operator fatigue during long hours.
   

Common Problems with the Kobelco 907
While the Kobelco 907 is generally reliable, like any piece of equipment, it is not immune to problems. Operators may encounter several issues, often related to the hydraulic system, engine, or undercarriage. Here are some of the most common problems:

1. Hydraulic System Issues
   Hydraulic problems are among the most common issues reported with the Kobelco 907. These can include:
   • Weak Hydraulic Power: Low hydraulic performance can be caused by issues with the hydraulic pump, low oil levels, or clogged filters. This results in reduced digging force and slower operations.
     
   • Leaking Hydraulic Hoses: Over time, hoses can wear out, crack, or become damaged, leading to hydraulic fluid leaks. This will compromise the system’s performance and may lead to severe damage if not fixed.
     
   • Sticking Valves: If the hydraulic valves become clogged or damaged, the machine’s movements may become jerky, or the excavator may not respond as expected when activating certain functions.
     
2. Engine Problems
   The engine of the Kobelco 907 is generally robust, but common issues include:
   • Starting Problems: If the engine has trouble starting, it may be due to battery issues, faulty wiring, or problems with the fuel system.
     
   • Overheating: Overheating can occur due to low coolant levels, a blocked radiator, or a malfunctioning water pump.
     
   • Low Power Output: Low engine power may be due to clogged air filters, dirty fuel injectors, or a failing turbocharger.
     
3. Undercarriage Wear
   The undercarriage of the Kobelco 907, including the tracks and rollers, is subjected to a lot of stress during operation. Common issues include:
   • Track Tension Problems: Tracks can become too loose or too tight over time, causing uneven wear and potential damage to the undercarriage components.
     
   • Wear and Tear on Tracks: Continuous operation in rough conditions can lead to track links wearing out faster. It is essential to regularly inspect the tracks for damage and replace them when necessary.
     
   • Roller and Idler Damage: The rollers and idlers can wear out and, if not maintained, may cause excessive track tension, leading to further damage.
     
4. Electrical System Failures
   Electrical issues, such as malfunctioning sensors or faulty wiring, can lead to:
   • Inconsistent Operation: If sensors that monitor hydraulic pressure or engine performance fail, the machine may exhibit inconsistent behavior.
     
   • Battery Drain: Electrical system issues or parasitic battery drain can prevent the engine from starting or cause the battery to discharge prematurely.
     

Diagnosing and Fixing Problems on the Kobelco 907
When issues arise with the Kobelco 907, proper diagnosis is crucial. Here's how you can identify and troubleshoot common problems:
1. Check Hydraulic Fluid and Filters
If you notice weak hydraulic performance, the first step is to inspect the hydraulic fluid levels and quality. Low or contaminated fluid can severely impact performance. If the fluid is clean and at the correct level but problems persist, it’s time to check the filters and hydraulic lines for blockages or leaks.
2. Inspect the Engine
If starting problems arise, test the battery to ensure it’s properly charged. Check the starter motor and fuel system for clogs or leaks. If the engine is overheating, check the coolant levels and clean the radiator to improve airflow. Also, inspect the water pump and thermostat for wear.
3. Undercarriage Inspection
Inspect the tracks regularly for signs of wear or damage. If the tracks are too tight or loose, adjust the tension according to the manufacturer’s recommendations. Regularly lubricate the rollers, idlers, and other moving parts to prevent excessive wear.
4. Electrical and Sensor Check
If electrical issues arise, start by testing the battery and wiring connections. Use a multimeter to check the voltage and ensure there are no short circuits or parasitic drains. If sensors are faulty, replacing them will restore proper machine functions.
Maintenance Tips for the Kobelco 907
To keep your Kobelco 907 running efficiently, regular maintenance is key. Here are some practical tips for ensuring the longevity of the machine:

1. Regularly Change Hydraulic Fluid
   Follow the manufacturer’s guidelines on hydraulic fluid change intervals. Regularly replace hydraulic filters to prevent contamination and improve system performance.
   
2. Check for Leaks
   Regularly inspect the machine for leaks, especially in the hydraulic system and undercarriage. Leaks can lead to loss of power and damage to components, so fixing them promptly is essential.
   
3. Monitor Engine Health
   Ensure that air filters, fuel filters, and coolant levels are checked and maintained. Replace the fuel filters at regular intervals to prevent clogging. Clean the air filters periodically to prevent engine strain and overheating.
   
4. Track and Undercarriage Care
   Perform regular inspections of the tracks, rollers, and undercarriage components. Replace or repair damaged tracks and rollers immediately to avoid further damage to the undercarriage.
   
5. Electrical System Inspections
   Inspect the electrical wiring and connections regularly to prevent corrosion and failure. Clean any corrosion from battery terminals and ensure all connections are tight and secure.
   

Real-World Example: A Contractor’s Experience with the Kobelco 907
A contractor working on a tight residential site was using the Kobelco 907 for digging and trenching tasks. After several weeks of heavy use, the machine began showing signs of weak hydraulic performance. A quick inspection revealed that the hydraulic fluid was low due to a small, undetected leak in one of the hoses. The contractor replaced the fluid, fixed the leak, and replaced the hydraulic filters. Afterward, the machine’s performance returned to normal, demonstrating the importance of regular maintenance and timely issue resolution.
Conclusion
The Kobelco 907 is a reliable and powerful excavator for a wide range of applications, especially in urban environments where space is limited. However, like any machinery, it requires regular maintenance and occasional repairs to keep it running smoothly. By understanding the common issues associated with the 907 and knowing how to diagnose and address them, operators can ensure that the machine remains in top condition, improving its performance and extending its lifespan. Regular checks of the hydraulic system, engine, undercarriage, and electrical components will go a long way in preventing unexpected downtime and costly repairs.