Adding a Third Spool to the WA320-6/7/8 Loader

[MikePhua]

The WA320 series wheel loaders from Komatsu have become a staple in construction, material handling, and various other industries requiring heavy-duty equipment. Known for their powerful hydraulics and versatile capabilities, these loaders are often used for tasks ranging from lifting and digging to pushing heavy materials. However, one of the most common modifications made to improve the functionality of these machines is adding a third hydraulic spool valve. This addition can vastly enhance the loader's ability to operate multiple attachments and tools simultaneously, making it even more efficient for operators.
Understanding the WA320-6/7/8 Loader
Komatsu’s WA320 series has been a popular choice for operators needing a balance between power and maneuverability. The WA320-6, WA320-7, and WA320-8 models are equipped with a reliable diesel engine and powerful hydraulics designed to handle a wide range of tasks. These machines are known for their fuel efficiency, strong lifting capacities, and ability to work in tight spaces due to their relatively compact design compared to larger wheel loaders.
Hydraulic systems are integral to the performance of these loaders, controlling a variety of functions, from the bucket movement to the steering mechanism. The loader comes standard with two hydraulic spools, allowing operators to control two functions simultaneously. However, certain tasks may require the use of additional attachments such as grapples, augers, or even snowplows, which may necessitate a third hydraulic function.
Why Add a Third Hydraulic Spool?
A third hydraulic spool allows the loader to operate additional attachments that require hydraulic power. The most common applications for a third spool include:

1. Operating a Grapple: When handling bulk materials such as logs, scrap metal, or demolition debris, a grapple attachment can be used. The third spool can control the opening and closing of the grapple while the first two spools handle other functions, such as lifting and tilting.
   
2. Adding a Forklift Attachment: Forklifts or pallet forks are often used with wheel loaders to move materials more efficiently. A third spool enables the loader to operate the forklift attachment’s tilt and fork adjustments.
   
3. Controlling a Hydraulic Hammer: In some construction or demolition environments, a hydraulic breaker or hammer is used to break concrete or rock. The third spool can control the hammer’s operation, providing additional flexibility for the operator.
   
4. Increasing the Number of Simultaneous Functions: For tasks that require the operation of multiple attachments, such as loading, lifting, and moving material at the same time, a third spool provides the necessary hydraulic power to make the process smoother and more efficient.
   

Modifying the WA320 Loader with a Third Spool
To add a third spool to the WA320-6, -7, or -8 models, the loader’s hydraulic system must be modified. This process can be complex and requires careful consideration of the loader's existing hydraulic system, attachments, and intended use.

1. Planning the Installation:
   • Before beginning the modification, it is crucial to determine the exact requirements of the hydraulic system. This includes the flow rate and pressure requirements for the third spool.
     
   • Operators must also decide whether to use a dedicated third spool lever or incorporate the third spool into the existing control system. In some cases, an additional control valve may be required to manage the third spool independently.
     
2. Hydraulic Circuit Modification:
   • The most common method for adding a third spool is by installing an additional hydraulic valve. This valve will control the third spool’s function, allowing the operator to control the additional hydraulic lines that power new attachments.
     
   • The modification typically requires tapping into the loader's main hydraulic supply and returning hydraulic fluid to the tank after passing through the new valve.
     
   • It is important to match the spool valve’s pressure rating with the machine's existing system to ensure compatibility and prevent damage to the hydraulic components.
     
3. Installing the Third Spool Valve:
   • A third spool valve can be installed by either mounting it near the operator’s seat or integrating it into the existing joystick control system. In some cases, the third spool can be linked to a button or dial that allows easy activation.
     
   • The new valve should be securely mounted, with all hoses and connections properly tightened to prevent leaks or failures under pressure.
     
   • If the loader already has auxiliary hydraulic lines, these lines can be rerouted to the new third spool valve. If no auxiliary lines are present, the modification will include running new hydraulic lines from the valve to the rear of the loader or the front-mounted attachment.
     
4. Electrical Integration:
   • For modern loaders that feature electronic control systems, the third spool valve may need to be integrated into the machine’s electronics. This could involve configuring the machine’s control panel to recognize and activate the third hydraulic function.
     
   • Some loaders may require programming adjustments to the ECU (Engine Control Unit) to support the added spool. These changes might need to be performed by a trained technician or authorized Komatsu dealer.
     
5. Testing and Calibration:
   • Once the modification is complete, the hydraulic system should be thoroughly tested to ensure all components are functioning correctly. This includes checking for leaks, ensuring the spool engages properly, and confirming that the flow rate and pressure are sufficient for the desired attachments.
     
   • A technician should also calibrate the system to ensure smooth operation of the third spool. This involves adjusting the flow control to match the hydraulic needs of the added attachments.
     

Common Issues and Solutions

1. Hydraulic Leaks:
   • Hydraulic leaks can occur if the connections to the new third spool valve are not properly tightened or sealed. These leaks can result in a loss of hydraulic power and, in extreme cases, damage to the hydraulic components. Regular inspection of the modified system is essential to catch any leaks early.
     
2. Overloading the Hydraulic System:
   • If the third spool is used with attachments that demand more hydraulic power than the system can supply, it may lead to overheating or failure of the hydraulic pump. Operators should carefully match the hydraulic power requirements of the attachments with the capabilities of the WA320’s hydraulic system.
     
3. Control Incompatibility:
   • In some cases, operators may find that the new control system for the third spool is not intuitive or requires additional training. A well-designed interface, such as an integrated joystick control, can make the transition smoother, but adjustments may still be needed to ensure the operator can efficiently use the third function.
     
4. Under-Performance of Attachments:
   • If the third spool does not provide sufficient hydraulic flow or pressure, the attachments may not function as expected. This could result from poor calibration, faulty valves, or incorrect installation. Ensuring that all components are properly sized and installed is key to preventing this issue.
     

Benefits of Adding a Third Spool

1. Increased Versatility: Adding a third spool opens up the loader to a wider range of attachments, improving its versatility on the job site. This allows operators to tackle more complex tasks without needing to switch machines or rely on additional equipment.
   
2. Improved Efficiency: With the ability to operate multiple attachments simultaneously, operators can complete tasks faster and with fewer interruptions. This is particularly beneficial on busy job sites where time is critical.
   
3. Cost Savings: By adding a third spool instead of purchasing additional machines, operators can save on equipment costs. The WA320 loader can be adapted to suit different jobs, reducing the need for a separate machine for each specific task.
   

Conclusion
The ability to add a third hydraulic spool to the Komatsu WA320-6/7/8 loaders significantly enhances their functionality, making them more versatile and capable of handling a broader range of attachments and tasks. Whether for construction, landscaping, or material handling, the added hydraulic capacity allows the loader to operate more efficiently, saving both time and money. However, adding a third spool requires careful planning, correct hydraulic integration, and proper installation to avoid potential system failures. When done correctly, this modification can extend the loader's capabilities and make it an even more valuable asset to your fleet.