The Kobelco 905 Excavator is a powerful and efficient machine, but over time, some users may encounter issues with the steering and brake system. These problems can cause difficulty in steering, ineffective braking, or even complete failure to stop, which affects both operational efficiency and safety. Below is a guide to troubleshooting and resolving steering and brake issues on the Kobelco 905 Excavator.
1. Common Steering and Brake Problems
Steering and brake issues often present as:

• Brake Failure: The brakes do not engage properly, making it difficult to stop the machine safely.
  
• Difficulty Steering: The steering becomes stiff or unresponsive, making maneuvering the machine challenging.
  
• Uneven Braking: The braking force is inconsistent, with one side potentially weaker or entirely ineffective.
  

• Hydraulic System Failure: The steering and braking systems rely on hydraulic oil for operation. If the hydraulic oil is contaminated, the hydraulic pump is faulty, or the oil pressure is too low, it can result in unresponsive brakes and steering.
  
• Worn Brake Pads: Over time, the brake pads can wear down, leading to reduced braking efficiency and slower response.
  
• Air in the Hydraulic System: Air in the hydraulic lines can cause unstable oil pressure, which affects the brakes and steering.
  
• Faulty Hydraulic Valves: Malfunctions or leaks in the hydraulic control valves can obstruct the flow of hydraulic fluid, disrupting the brake and steering functions.
  

• Check Hydraulic Oil: Start by inspecting the hydraulic oil quality and level. If the oil is contaminated or low, replace it and clean the hydraulic lines.
  
• Inspect the Hydraulic Pump: Verify the operation of the hydraulic pump to ensure it is supplying adequate oil pressure. If the pump is malfunctioning, it should be repaired or replaced.
  
• Check Brake Pads: Examine the brake pads for wear. If they are significantly worn down, replace them to restore braking effectiveness.
  
• Examine Hydraulic Valves: Inspect the hydraulic control valves for leaks or malfunction. If any faults are found, repair or replace the valves.
  
• Check for Air in the System: Ensure no air has entered the hydraulic system. If air is present, bleed the system and refill with hydraulic oil to stabilize oil pressure.
  

• Replace Hydraulic Oil: If the oil is contaminated, replace it with fresh hydraulic oil and clean the entire hydraulic system.
  
• Replace Brake Pads: If the brake pads are worn, replace them with new ones to ensure proper braking.
  
• Repair or Replace Hydraulic Pump and Valves: If the hydraulic pump or control valves are faulty, have them professionally repaired or replaced.
  
• Remove Air from the System: Purge any air from the hydraulic system to restore stable oil pressure.
  

• Regularly Check Hydraulic Oil: Periodically inspect and replace the hydraulic oil to ensure the hydraulic system functions properly.
  
• Routine Brake System Inspections: Regularly check the brake pads for wear and replace them when necessary.
  
• Avoid Overloading: Avoid prolonged high-load operation, as this can cause excessive wear on the steering and braking systems.
  
• Periodic Hydraulic System Checks: Regularly check the hydraulic components for leaks and ensure smooth oil flow.
  

The Kobelco SK025 is a widely used mini excavator, known for its efficient performance and compact design, making it ideal for tasks in confined spaces. However, some users have encountered an issue where the travel motor becomes jammed, preventing the machine from moving or causing it to stop unexpectedly during operation. Below are troubleshooting steps and solutions for resolving this issue.
1. Causes of Travel Motor Jamming
The travel motor jamming issue is often related to hydraulic system failures, oil blockages, or internal component wear. When certain parts of the hydraulic system malfunction, the travel motor may not operate properly. Common causes include:

• Hydraulic Oil Contamination: Contaminants in the hydraulic oil can obstruct smooth operation, impacting the performance of the travel motor.
  
• Hydraulic Pump Failure: If the hydraulic pump fails, it may not supply enough oil flow to the travel motor, causing it to malfunction.
  
• Internal Wear in the Motor: Prolonged use can cause internal components of the travel motor (e.g., gears, bearings) to wear out, potentially leading to jamming.
  

• Check Hydraulic Oil: Start by checking the oil level and oil quality. If the oil is contaminated or the oil level is low, the hydraulic system may not function properly. It is recommended to replace the hydraulic oil and clean the oil lines.
  
• Inspect the Hydraulic Pump: Check the hydraulic pump’s operation to ensure it’s providing the correct oil flow. If the pump is malfunctioning, it should be repaired or replaced.
  
• Examine the Motor: Disassemble the travel motor and inspect its internal components, such as gears and bearings, for wear or damage. If damaged components are found, replace them promptly.
  
• Inspect Control Valve: Ensure that the control valve is functioning correctly. A stuck or faulty valve may cause improper oil flow, leading to jamming of the travel motor.
  

• Clean and Replace Hydraulic Oil: If the hydraulic oil is contaminated, replace it and clean the oil lines to restore the system’s proper functioning.
  
• Repair or Replace the Hydraulic Pump: If the hydraulic pump is defective, it is best to either repair it or replace it with a new one.
  
• Replace Worn Components: If the internal components of the travel motor, such as gears or bearings, are worn out, replace the damaged parts to restore smooth operation.
  
• Replace Control Valve: If the control valve is faulty, it will need to be repaired or replaced to ensure proper oil flow.
  

• Regular Hydraulic Oil Changes: Regularly check and replace the hydraulic oil to keep the system clean and prevent the accumulation of contaminants.
  
• Routine Hydraulic System Inspections: Periodically check the hydraulic pump, motor, and control valves for any signs of wear or malfunction. Address any potential issues before they escalate.
  
• Avoid Overloading the Machine: Avoid prolonged operation under high load conditions to reduce wear on the travel motor and hydraulic system components.
  

The Kobelco SK135 is a powerful and efficient mid-sized crawler excavator, widely used in construction, civil engineering, and mining applications. Known for its excellent performance, robust power, and excellent handling, it has become a popular choice for a variety of projects. Below is a review based on user feedback and experiences with the Kobelco SK135 excavator.
1. Performance and Power
The Kobelco SK135 is equipped with a powerful engine that provides stable power output, meeting the demands of various earthmoving and heavy digging tasks. Its hydraulic system is also excellently designed, ensuring stable operation and sufficient power support in complex work environments. Many users report that this excavator can easily handle most working environments, from everyday construction operations to complex earth excavation tasks.
2. Operation and Handling
The SK135 is known for its excellent operational control. The hydraulic system responds quickly, and the joystick controls are comfortable, allowing for efficient and precise work. The cabin is spacious with excellent visibility, enabling operators to easily manage all of the machine’s functions. The operation interface is user-friendly, making it easy for operators with varying levels of experience to quickly get up to speed and work efficiently.
3. Comfort and User-Friendly Design
Kobelco has paid significant attention to comfort in the SK135’s cabin design. The seat is adjustable in multiple directions to minimize physical strain during long working hours. Additionally, the air conditioning system, shock-absorbing seat, and low noise levels further enhance the operator’s comfort. For operators working long shifts, these ergonomic features contribute to higher efficiency and overall comfort.
4. Fuel Efficiency
The Kobelco SK135 delivers good fuel efficiency for a mid-sized excavator. Despite its size, its energy-efficient design helps reduce fuel consumption, saving operational costs over time. Many users report that even under heavy load, fuel consumption remains relatively low.
5. Maintenance and Upkeep
Maintenance for the SK135 is relatively straightforward, with long service intervals and easy access to components. Regular maintenance tasks include hydraulic oil and filter changes, as well as engine and hydraulic system checks. The availability of OEM parts and an extensive repair network ensure reliable long-term operation. With proper maintenance, the SK135 remains in high-performing condition over time.
6. Drawbacks and Areas for Improvement
While the SK135 excels in many areas, there are some user-reported drawbacks. Some users noted that the machine has a slower startup time, especially under heavy load, with the engine taking longer to reach full operating speed. Although the machine performs well in most conditions, a few users also observed that its fuel efficiency could be affected in extreme operating environments.
Conclusion
Overall, the Kobelco SK135 is a powerful, efficient, and easy-to-operate mid-sized crawler excavator, ideal for various construction and earthmoving projects. Its excellent handling, comfortable operating environment, and good fuel efficiency make it a top choice for many medium to large-scale projects. Despite a few minor drawbacks, the SK135 remains a reliable and high-performing excavator capable of handling demanding work conditions.

The Kobelco SK25SR is a compact and efficient mini excavator widely used in urban construction, landscaping, and operations in confined spaces. Its compact design and powerful performance make it a top choice for many users. Below is a review based on feedback and experiences with the Kobelco SK25SR excavator.
1. Performance and Power
The Kobelco SK25SR is equipped with a highly efficient engine that provides strong power to meet various earthmoving, material handling, and landscaping needs. Many users report that, despite being a small machine, its hydraulic system performs exceptionally well, handling heavy-duty tasks and complex environments with ease.
2. Compact Design and Maneuverability
The SK25SR features a compact design, making it ideal for working in narrow spaces, particularly in urban environments, tight construction sites, and roadwork. Its small turning radius allows for easy maneuverability, enabling the machine to work efficiently in confined spaces. This flexibility makes the SK25SR suitable for a wide range of complex environments.
3. Operation and Comfort
The cabin of the SK25SR is designed for comfort, offering a spacious interior and excellent visibility. The layout of the control sticks and pedals is ergonomic, making operation simple and comfortable. The responsive control system allows operators to easily perform digging, material handling, and other tasks. The precise hydraulic control further enhances the machine’s efficiency and stability, reducing operator fatigue.
4. Fuel Efficiency
The SK25SR is known for its excellent fuel efficiency, with many users reporting that fuel consumption remains low even during heavy or prolonged operations. Compared to other similar mini excavators, the SK25SR’s fuel economy is better, helping to reduce long-term operating costs.
5. Maintenance and Upkeep
Maintenance for the Kobelco SK25SR is relatively straightforward, with users reporting good durability and ease of component replacement. Regular maintenance tasks include hydraulic oil changes, battery checks, and air filter cleaning. Proper upkeep helps extend the life of the equipment. Additionally, the availability of OEM parts and repair services is convenient, ensuring reliable long-term operation.
6. Drawbacks and Limitations
While the SK25SR excels in many areas, some users have pointed out that its performance can be slightly limited in extreme working conditions. For example, when dealing with very hard soil or rock, the machine’s power and efficiency may decrease. Additionally, some users noted that the machine’s startup speed can be slow, particularly in tasks requiring a fast response.
Conclusion
Overall, the Kobelco SK25SR is a highly efficient, compact mini excavator, ideal for various narrow space and small to medium-sized construction projects. Its excellent fuel economy, comfortable operation, and powerful hydraulic system make it a popular choice for many users. Despite some minor drawbacks, the SK25SR remains a reliable and versatile mini excavator, well-suited for a variety of work environments.

The Kobelco SK30UR is a compact mini excavator that is widely used in urban construction, landscaping, and operations in confined spaces due to its high efficiency and small size. Below is a review based on user feedback and experiences with the Kobelco SK30UR excavator.
1. Performance and Power
The Kobelco SK30UR is equipped with a powerful engine that provides ample power for various tasks. Despite being a small excavator, its hydraulic system performs exceptionally well, easily handling most earthmoving, digging, and demolition tasks. Many users report that the SK30UR maintains stable performance even in more complex working environments.
2. Compact Design and Maneuverability
The SK30UR’s compact design makes it ideal for operations in tight spaces, particularly in urban construction, landscaping, and roadwork. It has a small turning radius, allowing it to maneuver easily in confined areas. For users requiring high mobility, this excavator is an excellent choice.
3. Operation and Comfort
In terms of operation, the SK30UR features a spacious and comfortable cabin, with an easy-to-use control system suitable for operators of varying skill levels. The layout of the joystick and pedals is well-designed to reduce fatigue during extended working hours. Additionally, the hydraulic system is very responsive, ensuring smooth and precise digging and other tasks.
4. Fuel Efficiency
The SK30UR excels in fuel efficiency, with many users noting that fuel consumption remains low even during extended periods of use. Compared to similar models, the fuel economy of this excavator is superior, helping users reduce long-term operational costs.
5. Maintenance and Upkeep
Maintenance for the Kobelco SK30UR is relatively simple, with users reporting long service intervals and easy component replacements. Regular maintenance tasks like checking hydraulic oil and replacing air and fuel filters help extend the machine’s service life. Additionally, the availability of parts and repair services is excellent, ensuring reliable long-term operation.
6. Drawbacks and Areas for Improvement
While the SK30UR performs well in many areas, some users have mentioned that its startup speed is somewhat slow, especially under heavy load, requiring more time to reach optimal working speed. Furthermore, although it has a small turning radius, navigating in extremely narrow environments can still be challenging.
Conclusion
Overall, the Kobelco SK30UR is an efficient, compact mini excavator suitable for a variety of work environments. Its good fuel efficiency, excellent operating comfort, and strong performance make it an ideal choice for many small to medium-scale construction and urban projects. While it has some minor drawbacks, the SK30UR is a highly reliable and well-rounded excavator.

When using Komatsu excavators, the safety relay is often a critical component that users focus on, especially when troubleshooting. The safety relay plays a key role in ensuring the safe operation of the machine by controlling and monitoring multiple safety systems. Below are some common questions and solutions regarding the safety relay in Komatsu excavators.
1. Purpose of the Safety Relay
The safety relay in a Komatsu excavator typically monitors essential safety systems, such as oil pressure, fuel system, and battery voltage. It ensures that when a safety issue arises, the electrical circuit is automatically disconnected to prevent further mechanical damage or unsafe operation. The proper functioning of the safety relay is vital for both the machine's stability and the operator’s safety.
2. Symptoms of Safety Relay Failure
The most common symptom of a safety relay failure is when the excavator fails to start or suddenly shuts down during operation. This typically indicates that the relay is not correctly receiving or transmitting signals, preventing the machine from functioning properly. Additionally, a faulty relay may prevent systems like oil pressure or fuel pumps from starting, affecting overall performance.
3. Troubleshooting
When facing a safety relay issue, the first step is to check the battery voltage, as low voltage can cause the relay to malfunction. Next, ensure all electrical connections are secure, especially the relay’s terminal connections, which should be clean, tight, and free of corrosion. If both the battery voltage and electrical connections are normal, a multimeter can be used to check the relay’s operation and ensure signal transmission is not blocked.
4. Replacing the Safety Relay
If the safety relay is found to be faulty, it will usually need to be replaced. It is important to choose an OEM relay that matches the specific Komatsu excavator model to ensure proper functioning and safety. The replacement process should follow the guidelines provided in the operator’s manual to ensure the relay is installed and wired correctly.
5. Maintenance and Care of the Safety Relay
Regularly inspecting the safety relay’s condition, keeping the electrical system clean, and maintaining proper electrical contact are essential to extending the relay's lifespan. Users should clean terminal connections, check the battery voltage periodically, and monitor any electrical system anomalies to reduce the risk of relay failure.
Conclusion
The safety relay in a Komatsu excavator plays a crucial role in ensuring safe operation and prolonging the machine’s lifespan. By performing regular checks and maintenance, and promptly addressing relay failures, users can ensure efficient and safe operation of their excavators.

The Komatsu PC40 excavator is a highly versatile mini excavator, commonly used in construction, civil engineering, and agricultural projects. Known for its excellent performance and efficiency, it has become a top choice for many operators. Below is a review based on user feedback and experiences with the Komatsu PC40.
1. Performance and Reliability
The Komatsu PC40 is equipped with a powerful engine that provides stable power output, meeting the demands of various work environments. Its hydraulic system is excellent, offering smooth operation, making it ideal for tasks such as digging, leveling, and material handling. Users generally report that the PC40 performs efficiently in a variety of soil conditions, particularly excelling in soft or muddy environments.
2. Ease of Operation and Comfort
The PC40's operating system is well-designed and user-friendly, suitable for operators with varying levels of experience. The cabin is spacious and comfortable, with good visibility, and the layout of controls and pedals is ergonomically designed to minimize operator fatigue. Many users have praised the driving experience and human-centric design, especially for extended working hours, as it maintains operator comfort.
3. Fuel Efficiency
The Komatsu PC40 is known for its impressive fuel efficiency. Many users have reported that even during long periods of high-intensity work, fuel consumption remains within a reasonable range. Compared to other similar models, the PC40’s fuel economy is a significant advantage, helping users save on long-term operational costs.
4. Maintenance and Upkeep
Maintenance of the PC40 is relatively simple, and users have generally found it easy to maintain. Routine maintenance includes changing hydraulic oil, checking the battery, and cleaning the air filter. User feedback indicates that the machine is durable, and regular maintenance significantly extends its service life. Additionally, the availability of OEM parts and repair services is high, which ensures quick repairs in case of any breakdowns.
5. Drawbacks of the Komatsu PC40
While the Komatsu PC40 excels in many areas, some users have reported that transportation costs can be higher due to its size and weight. In certain regions, transporting the machine might be more expensive compared to other mini excavators. Additionally, some users have mentioned that the turning radius is larger, which requires careful maneuvering in tight spaces.
Conclusion
Overall, the Komatsu PC40 is a highly efficient, easy-to-operate, and fuel-efficient mini excavator. Whether used on construction sites, for earthworks, or in agriculture, the PC40 delivers excellent performance. With regular maintenance, its durability is also highly reliable. While there are some minor drawbacks, such as transportation costs and turning radius, the PC40 remains an excellent choice for medium to small-scale projects.

The Komatsu PC45 is a powerful mini excavator commonly used in construction, excavation, and landscaping projects. During operation, users may encounter issues with the blade control cable location, which can affect the machine's performance and efficiency. Below are some common problems and solutions related to the blade control cable location on the Komatsu PC45.
1. Purpose of the Blade Control Cable
The blade control cable on the Komatsu PC45 is responsible for transmitting control signals to the blade's action system, ensuring that the blade moves smoothly for lifting and tilting. The position and installation quality of the cable directly impact the smoothness and precision of the blade operation.
2. Common Cable Location Issues
Some users have reported issues with incorrect positioning of the blade control cable, leading to delayed or inaccurate blade movements. This problem is often caused by cable wear, looseness, or improper installation. Over time, the cable may become worn out, which can affect its performance and should be checked and replaced as needed.
3. Checking and Adjusting the Cable Position
To ensure the correct positioning of the blade control cable, start by inspecting the cable for signs of wear or damage, particularly at the connection point with the blade. Also, make sure the cable is not too loose or too tight—too loose may cause inaccurate control, while too tight could lead to faster wear of the cable.
For adjustments, it is recommended to refer to the specific instructions in the operator's manual. In most cases, adjusting the cable tension can improve the blade’s response time and operational accuracy.
4. Cable Replacement and Maintenance
If you find significant wear or damage to the cable, it's best to replace it promptly. When replacing, always choose the original Komatsu PC45 cable to ensure compatibility and performance. Additionally, regularly clean the cable to prevent dust or debris accumulation, which can prolong the cable’s life.
Conclusion
Proper installation and maintenance of the blade control cable on the Komatsu PC45 are essential for the machine's smooth operation. By regularly checking the cable position, adjusting tension, and replacing worn components, users can ensure that the blade system operates efficiently and effectively, improving overall work productivity.

The Komatsu PC50 is a widely used mini excavator known for its compact design and powerful performance, making it ideal for various small-scale construction and civil engineering projects. For many users, selecting the right bucket is essential to ensuring optimal machine performance and work efficiency. Here’s a guide to common issues and advice regarding Komatsu PC50 excavator buckets.
1. Bucket Types and Size Selection
The Komatsu PC50 supports a variety of bucket types and sizes, allowing users to choose the right one based on their specific work requirements. Common bucket types include standard buckets, wide buckets, and deep digging buckets. When selecting a bucket, key factors to consider include soil type, digging depth, and the required load capacity.

• Standard Bucket: Suitable for general earthmoving tasks, especially in soft soil conditions.
  
• Wide Bucket: Ideal for large-area soil clearing and shallow digging work.
  
• Deep Digging Bucket: Used for tasks requiring deeper digging, particularly in hard soils or rocky areas.
  

• Avoid Overloading: When using the bucket, avoid overloading it, especially in softer soils, to prevent damage to the bucket or overloading the machine.
  
• Proper Bucket Angle: Adjusting the bucket angle based on the task at hand can improve digging efficiency.
  

The Komatsu PC50MR-2 is a compact mini excavator known for its high performance and versatility, widely used in various construction and civil engineering projects. However, like any machine, users may encounter some common issues during operation. Below are some frequently discussed problems and their solutions for the Komatsu PC50MR-2 excavator.
1. Unstable Operation or Engine Irregularities
Some users have reported that the engine occasionally runs unstable or unevenly. This is often due to issues with the fuel system or a clogged air filter. Regularly checking and replacing the fuel filter and air filter can help resolve this problem and keep the engine running smoothly.
2. Hydraulic System Issues
Common hydraulic system issues on the PC50MR-2 include sluggish or imprecise movements. The typical cause is a problem with hydraulic fluid quality or low fluid levels. Ensuring the hydraulic oil is of the correct viscosity and replacing the hydraulic filter can address this. Failure to replace the hydraulic oil regularly or build-up in the system can cause these issues.
3. Control System Failures
Some operators have reported electronic control system failures, which could be caused by poor connections, sensor malfunctions, or a low battery. Diagnosing this issue usually involves an electrical inspection to ensure all connections are clean and tight.
4. Slow Throttle Response
Several operators have noted a delayed throttle response, which results in the machine not reacting quickly enough. This could be caused by issues with the throttle control system or fuel supply blockages. Checking the throttle control cable and fuel pump for clogs or wear is recommended.
5. Rapid Wear on Tracks
The tracks on the PC50MR-2 may wear out faster in certain conditions, especially when operating on rough, rocky terrain. To extend the lifespan of the tracks, it’s important to avoid prolonged use on rough surfaces and to regularly check the track tension.
Conclusion
While the Komatsu PC50MR-2 is a reliable and powerful mini excavator, users may encounter some common issues over time. Through regular maintenance and inspections, many of these problems can be avoided or resolved. Proper care and upkeep can extend the machine's lifespan and enhance its work efficiency.