Shimming Issues with Hitachi 120 Conversion Kits: Troubleshooting and Solutions

[MikePhua]

The Hitachi 120 excavator is a widely used machine in the construction and excavation industry. Known for its robust performance, it is often involved in tasks that demand precision and reliability. One common issue that some operators face is related to conversion kits and shimming, which can affect the performance of the machine and lead to increased maintenance costs. This article explores the common problems related to shimming during conversion kit installation, provides potential solutions, and offers tips for resolving these issues effectively.
Understanding Conversion Kits and Shimming in Excavators
A conversion kit in heavy machinery is typically used to upgrade, modify, or replace existing parts to improve performance, compatibility, or efficiency. For the Hitachi 120 excavator, conversion kits may be used to change certain hydraulic systems, increase lifting capacities, or adapt the machine to different working conditions.
Shimming, on the other hand, refers to the process of inserting thin pieces of material (shims) into gaps between parts to achieve proper alignment, adjustment, or clearance. In the context of an excavator conversion kit, shimming is often necessary to ensure that the newly installed components fit properly and function correctly within the system.
Common Shimming Problems During Conversion Kit Installation

1. Incorrect Shim Thickness: One of the most frequent issues during the conversion process is using incorrect shim thickness. If the shim is too thick or too thin, it can lead to improper alignment, increased friction, or inadequate support for the components, affecting the overall performance of the conversion kit.
   Solution: Always refer to the manufacturer’s specifications for the correct shim thickness. Measure the gap carefully before choosing a shim and ensure it matches the required dimensions.
   
2. Shim Deformation: Over time, shims may deform due to constant pressure or heat generated by the machine’s operation. This can cause the shim to lose its effectiveness, resulting in poor performance or mechanical failure.
   Solution: Use high-quality shims made from durable materials that can withstand the pressure and heat typical in excavator applications. Replace deformed or worn-out shims immediately to maintain optimal performance.
   
3. Misalignment After Installation: Even after shimming, misalignment can occur if the shim is not correctly positioned or if the parts involved in the conversion process were not properly aligned to begin with. This misalignment can lead to issues like uneven wear, difficulty in operation, or premature failure of the components.
   Solution: Before installing the conversion kit, ensure all components are aligned correctly. Check the positioning of the shims and confirm that they are seated properly before tightening any bolts or securing parts.
   
4. Excessive Vibration: Improper shimming can cause parts to move slightly during operation, leading to increased vibration. This is particularly problematic in an excavator, as excessive vibration can lead to faster wear and tear on other parts of the machine.
   Solution: Tighten the components gradually and evenly during installation to reduce the chances of misalignment. Additionally, ensure that the shims are evenly distributed to prevent any parts from shifting during operation.
   
5. Hydraulic System Issues: In some cases, shimming issues can affect the hydraulic system, especially if the conversion kit involves hydraulic components. A misaligned hydraulic component can lead to inefficient fluid flow, pressure loss, or leaks.
   Solution: After installation, perform a thorough inspection of the hydraulic system, checking for leaks or pressure drops. Test the machine under normal operating conditions to ensure the hydraulic system is functioning as intended.
   

Best Practices for Shimming and Conversion Kit Installation

1. Consult the Manufacturer’s Manual: Always refer to the manufacturer’s guidelines for specific instructions regarding shim thickness, installation procedures, and compatibility with other components. Following the manufacturer's recommendations will help prevent most shimming issues.
   
2. Use Precision Tools: When selecting and installing shims, use precise measuring tools to ensure proper fit and alignment. This will minimize the chances of installing incorrect shims and prevent issues like misalignment or excessive wear.
   
3. Regular Inspections: After completing the conversion, perform regular inspections of the shims and the machine’s performance. Look for signs of misalignment, unusual vibrations, or changes in operational efficiency. Early detection of issues can save time and money on repairs.
   
4. Replace Worn Shims Promptly: If you notice any signs of shim deformation or wear, replace them immediately to avoid further damage to the machine. Regular maintenance of shims can significantly extend the life of your conversion kit and ensure optimal performance.
   
5. Hydraulic System Testing: If the conversion involves hydraulic components, it is essential to test the system thoroughly after installation. Check for leaks, pressure irregularities, and smooth operation to ensure that the shimming hasn’t disrupted the hydraulic flow.
   

Conclusion
Shimming issues during the installation of conversion kits on the Hitachi 120 excavator can cause a range of problems, from misalignment and vibration to hydraulic failures. By following best practices, using the correct materials, and performing thorough inspections, these issues can be minimized or avoided altogether. Proper installation and regular maintenance will ensure that your conversion kit operates efficiently, extending the lifespan of your excavator and improving its performance on the job site.
Whether upgrading the machine’s capabilities or making modifications for specific tasks, addressing shimming problems promptly will help maintain the Hitachi 120’s reputation as a reliable and high-performing excavator.