Installing Hydraulic Thumb Controls on the Hitachi EX200-2

[MikePhua]

The Hitachi EX200-2 and Its Excavator Lineage
The Hitachi EX200-2 is part of the EX series of hydraulic excavators that helped establish Hitachi as a global leader in construction machinery. Hitachi Construction Machinery, founded in Japan in 1970, has sold hundreds of thousands of excavators worldwide, with the EX200 series becoming a benchmark for mid-size machines in forestry, demolition, and land clearing. The EX200-2, introduced in the early 1990s, features a robust hydraulic system, reliable Isuzu engine, and a modular valve block design that makes it a favorite among mechanics and operators alike.
While the EX200-2 was not originally equipped with a hydraulic thumb, its architecture allows for relatively straightforward retrofitting. Adding a thumb dramatically increases productivity in tasks like brush clearing, rock handling, and demolition—especially when paired with a progressive link thumb that maintains grip throughout the boom’s range of motion.
Evaluating the Existing Hydraulic Configuration
Before installing a hydraulic thumb, the first step is to inspect the machine’s valve block and cab controls. Many EX and ZX series Hitachis include an unused auxiliary spool in the main control valve, which can be repurposed for thumb operation. This spool is typically capped and may require plumbing and activation via joystick or foot pedal.
Key inspection points include:

• Presence of an unused spool section in the valve block
  
• Availability of hydraulic ports for auxiliary lines
  
• Existing joystick configuration (check for thumb buttons or wiring harnesses)
  
• Presence or absence of a foot pedal for auxiliary control
  

If the machine lacks a foot pedal or joystick buttons, electrical-over-hydraulic (EOH) control systems can be added. These systems use solenoids and relays to actuate the auxiliary spool via joystick-mounted switches.
Components Required for Hydraulic Thumb Installation
A complete hydraulic thumb retrofit on the EX200-2 typically includes:

• Hydraulic thumb (preferably progressive link for full range grip)
  
• Auxiliary hydraulic lines from valve block to boom
  
• Control valve or activation solenoid
  
• Joystick with integrated thumb buttons or auxiliary switch
  
• Electrical harness and relay kit
  
• Mounting brackets and hardware
  

Progressive link thumbs offer superior control by maintaining consistent grip pressure throughout the boom’s arc. They are especially useful in forestry and demolition, where material handling precision is critical.
Installation Sequence and Technical Considerations
The installation process involves several stages:

• Remove access panels and inspect the valve block for an unused spool
  
• Install hydraulic lines from the spool to the boom, routing them through existing clamps or adding new supports
  
• Mount the thumb to the stick, ensuring proper alignment and clearance
  
• Install the joystick or auxiliary switch, wiring it to the solenoid or EOH controller
  
• Test the system under load, checking for leaks, response time, and full range motion
  

One technician in Ontario noted that the EX200-2’s valve block often includes a two-way auxiliary spool, originally intended for breaker kits. This spool can be repurposed for thumb operation with minimal modification. However, breaker kits typically offer one-way flow, so ensure the spool supports bi-directional control.
Cost and Time Estimates
Retrofitting a hydraulic thumb can cost between CAD $4,000 and $8,000 depending on thumb type, control system complexity, and labor rates. Progressive link thumbs are more expensive but offer better performance. Installation time ranges from 12 to 20 hours, with additional time required for electrical integration if joystick buttons are added.
Contractors often choose to install the thumb during machine purchase or overhaul to minimize downtime. Some dealers offer package deals that include thumb installation, auxiliary plumbing, and joystick upgrades.
Field Anecdotes and Operator Feedback
Operators who’ve transitioned from manual thumbs or no thumb at all consistently report increased productivity. One land clearer in Georgia shared that after renting a CAT 323F with a progressive link thumb, he couldn’t go back to a bare stick. The ability to grip, rotate, and stack debris without repositioning the machine saved hours on each job.
Another operator in the Pacific Northwest noted that his EX200-2 had an unused spool and was able to plumb the thumb himself using a joystick with integrated buttons. The retrofit took two days and transformed his machine’s versatility.
Recommendations for Owners and Buyers
Before purchasing an EX200-2 or planning a thumb retrofit:

• Confirm the presence of an auxiliary spool in the valve block
  
• Choose a progressive link thumb for maximum control
  
• Opt for joystick-mounted buttons over foot pedals for ergonomic operation
  
• Use high-quality hydraulic lines and fittings rated for excavator pressure
  
• Consult with a technician familiar with Hitachi systems to avoid compatibility issues
  

Buyers should also request clear photos of the valve block and cab controls when evaluating used machines. A clean machine with an unused spool and intact wiring harness can save thousands in retrofit costs.
Conclusion
Adding hydraulic thumb controls to the Hitachi EX200-2 is a practical upgrade that significantly enhances the machine’s capabilities. With its modular valve block and proven hydraulic system, the EX200-2 is well-suited for auxiliary integration. Whether clearing land, handling debris, or performing demolition, a properly installed thumb turns a reliable excavator into a precision tool. And in the world of heavy equipment, precision means profit.