Kobelco SK115SRDZ Bucket and Stick Slow Function Diagnosis

[MikePhua]

The Kobelco SK115SRDZ is a compact and highly efficient excavator used in a wide range of construction and earth-moving applications. This machine, known for its powerful hydraulic system and compact design, is ideal for working in urban environments and tight spaces. However, one common issue faced by operators is the slow operation of the bucket and stick functions, which can significantly affect productivity. In this article, we will explore the possible causes of this issue, common troubleshooting methods, and ways to resolve the problem, along with some insights into the history and evolution of Kobelco excavators.
Common Causes of Slow Bucket and Stick Movement
The slow movement of the bucket and stick on the Kobelco SK115SRDZ can be attributed to several factors, most of which are related to the hydraulic system or the control mechanisms. Here are some of the key reasons behind the slow response:

1. Low Hydraulic Fluid Levels
   Hydraulic systems rely on an adequate supply of fluid to maintain pressure and facilitate smooth operation. Low hydraulic fluid levels can lead to slow or jerky movements of the stick and bucket. It's crucial to regularly check the fluid levels and top them up as needed.
   
2. Hydraulic Pump Issues
   The hydraulic pump in the SK115SRDZ plays a crucial role in delivering the necessary pressure to operate the machine’s various functions. If the pump is worn out or malfunctioning, it might not generate enough pressure, resulting in slow operation. This can often be traced back to issues with the pump’s internal components, such as seals, valves, or the pump’s motor.
   
3. Clogged or Worn Hydraulic Filters
   Over time, hydraulic filters can become clogged with debris or wear out, restricting the flow of hydraulic fluid. This can lead to reduced efficiency in the hydraulic system, causing the bucket and stick functions to operate more slowly. Regularly replacing or cleaning filters can prevent this issue.
   
4. Faulty Control Valves
   Control valves regulate the flow of hydraulic fluid to the various parts of the excavator, including the bucket and stick. If these valves are not functioning properly, they may restrict fluid flow, causing the movements to become sluggish. A faulty control valve might need to be repaired or replaced to restore proper function.
   
5. Damaged Hoses or Fittings
   Damaged hydraulic hoses or loose fittings can result in hydraulic fluid leaks, which reduce pressure in the system and cause slow movements. Inspecting hoses for wear and checking fittings for leaks can help identify this problem early.
   
6. Low Ambient Temperature
   In colder environments, the hydraulic fluid may become too thick, especially in older machines or during winter months. This can cause sluggish operation of the hydraulic functions, including the bucket and stick. Using the right type of hydraulic fluid for the specific temperature conditions can alleviate this issue.
   

Diagnosing the Issue
To accurately diagnose the cause of slow bucket and stick movement, a step-by-step approach is essential. Here's how you can troubleshoot the issue:

1. Check Hydraulic Fluid Levels
   Start by checking the hydraulic fluid levels and top them up if necessary. Low fluid levels are the easiest issue to fix and should be ruled out first.
   
2. Inspect the Hydraulic System for Leaks
   Next, visually inspect all hydraulic hoses and connections for leaks. If any leaks are found, the affected hoses or fittings should be replaced to restore proper fluid pressure.
   
3. Examine the Hydraulic Pump
   If there are no leaks and the fluid level is sufficient, the next step is to check the hydraulic pump. Listen for unusual noises or vibrations, as these can be signs of pump failure. A pressure test can also be conducted to determine if the pump is delivering adequate pressure.
   
4. Inspect the Control Valves
   The control valves should be checked for proper operation. If the valves are sticking or malfunctioning, they may need to be cleaned or replaced.
   
5. Check Hydraulic Filters
   Remove and inspect the hydraulic filters for signs of clogging or damage. Clean or replace filters as necessary to ensure unobstructed fluid flow.
   
6. Test the Temperature and Fluid Viscosity
   Finally, check the ambient temperature and the viscosity of the hydraulic fluid. If the fluid is too thick due to low temperatures, consider using a winter-grade fluid or wait for the machine to warm up before use.
   

Solutions for Improving Bucket and Stick Performance
Once the cause of the slow bucket and stick movement has been identified, there are several steps that can be taken to restore full performance:

1. Regular Maintenance
   Regular maintenance of the hydraulic system is key to ensuring smooth operation. This includes checking fluid levels, replacing filters, and inspecting hoses for damage.
   
2. Pump Replacement or Repair
   If the hydraulic pump is found to be faulty, it may need to be repaired or replaced. A qualified technician can test the pump and determine whether it can be rebuilt or needs to be replaced entirely.
   
3. Valve Adjustment or Replacement
   If the control valves are malfunctioning, they may need to be adjusted or replaced. In some cases, cleaning the valves can improve their function.
   
4. Seal Replacement
   If any hydraulic seals are found to be damaged, they should be replaced to prevent fluid leaks and restore pressure.
   
5. Temperature Control
   In colder environments, consider using winter-grade hydraulic fluid to ensure proper flow. Also, ensure that the machine is allowed to warm up before heavy use, especially during winter months.
   

The Kobelco SK115SRDZ: A Compact Excavator with Power
Kobelco, a renowned Japanese manufacturer of construction machinery, has built a reputation for producing high-quality and durable excavators. The SK115SRDZ is part of the company's SR series of excavators, which are known for their compact design and exceptional fuel efficiency. The SR series is designed to offer powerful performance in tight spaces, making them ideal for urban construction, utility work, and other applications that require precision and maneuverability.
Since its introduction, the SK115SRDZ has been a popular choice for construction companies looking for a compact yet powerful machine. It boasts a powerful engine, advanced hydraulic systems, and a comfortable operator cabin, all of which contribute to its success in the industry.
Conclusion
The slow function of the bucket and stick on the Kobelco SK115SRDZ can be caused by several issues related to the hydraulic system, including low fluid levels, pump problems, clogged filters, faulty valves, and leaks. By following a systematic troubleshooting process, operators can diagnose and resolve the issue quickly. Regular maintenance and prompt repairs are key to ensuring that the machine continues to perform at its best. With its compact size and powerful performance, the Kobelco SK115SRDZ remains a valuable tool for contractors working in confined spaces.