Electro-Hydraulic Conversion Kits for Hitachi/John Deere Excavators: A Complete Guide

[MikePhua]

The transition from electric to hydraulic controls in older Hitachi EX-100/120/200/220 and equivalent John Deere excavators represents one of the most impactful upgrades available for these workhorse machines. This comprehensive guide examines the conversion process, benefits, and practical considerations for equipment owners and technicians.
Understanding the Control System Evolution
Original Electric Control System Characteristics

• Joystick-mounted potentiometers sending electrical signals
  
• Complex wiring harnesses with multiple connection points
  
• Proprietary control modules prone to obsolescence
  
• Expensive replacement components (single joystick $800-$1,200)
  

Hydraulic Control System Advantages

• Direct pilot pressure operation
  
• Simplified mechanical linkages
  
• Industry-standard components
  
• Reduced electrical failure points
  

Key Benefits of Conversion
Operational Improvements

• 25-40% faster control response time
  
• More precise machine movements
  
• Consistent performance in extreme temperatures
  
• Eliminates "dead zone" issues common in aged electric systems
  

Maintenance Advantages

• 60-70% reduction in control-related downtime
  
• Standardized, readily available parts
  
• Simplified troubleshooting
  
• No specialized diagnostic equipment required
  

Conversion Kit Components
A complete system typically includes:

• Hydraulic pilot control valves
  
• New joystick assemblies
  
• Pressure-reducing valves
  
• Mounting brackets and hardware
  
• Hydraulic line kits
  
• Comprehensive installation manual
  

Installation Process Overview
Phase 1: System Preparation

• Complete machine depressurization
  
• Electrical system disconnection
  
• Removal of existing control components
  

Phase 2: Hydraulic Integration

• Pilot pump pressure verification (should be 450-500 psi)
  
• Control valve mounting and alignment
  
• Hose routing and securement
  

Phase 3: Calibration and Testing

• Pilot pressure adjustments
  
• Control neutral calibration
  
• Full operational testing
  

Performance Comparison Data
Independent tests on EX200 conversions showed:

• 28% faster cycle times in loading applications
  
• 17% reduction in operator fatigue
  
• 35% improvement in fine grading precision
  

Cost Analysis
Typical Investment

• Conversion kit: $3,200-$4,800
  
• Professional installation: $1,500-$2,500
  
• Downtime: 16-24 hours
  

Return on Investment
Most operators recoup costs within:

• 400-600 working hours (contractors)
  
• 8-12 months (farm/ranch use)
  

Case Study: Excavation Contractor Success
A Midwest earthmoving company converted their fleet of five EX220s:

• Reduced annual control system repairs from $12,000 to $1,800
  
• Increased machine utilization from 68% to 82%
  
• Extended planned equipment lifespan by 3-5 years
  

Maintenance Requirements Post-Conversion
Daily Checks

• Pilot pressure verification
  
• Control linkage inspection
  
• Hydraulic fluid condition monitoring
  

Scheduled Service

• Annual valve block inspection
  
• Biennial hose replacement
  
• 500-hour hydraulic filter changes
  

Troubleshooting Common Issues
Symptom: Sluggish Controls
Possible Causes:

• Low pilot pressure
  
• Contaminated fluid
  
• Worn valve spools
  

Symptom: Control Drift
Possible Causes:

• Linkage adjustment needed
  
• Internal valve leakage
  
• Pressure regulator malfunction
  

Special Considerations
Cold Climate Operation

• Use ISO 32 hydraulic fluid below -20°C
  
• Consider tank heaters for extreme conditions
  
• Allow extended warm-up periods
  

High-Usage Applications

• Upgrade to high-durability hoses
  
• Install additional filtration
  
• Increase service frequency by 30%
  

Operator Training Recommendations

• Familiarization with new control feel
  
• Sensitivity adjustment techniques
  
• Emergency override procedures
  
• Proper shutdown sequences
  

Alternative Solutions Comparison
Option 1: Complete Conversion

• Best for machines with 5,000+ remaining hours
  
• Most comprehensive solution
  
• Highest upfront cost
  

Option 2: Partial Retrofit

• Addresses only problematic components
  
• Lower initial investment
  
• May require additional work later
  

Option 3: Electrical System Refurbishment

• Maintains original design
  
• Potentially shorter solution lifespan
  
• OEM parts availability challenges
  

Industry Trends and Future Outlook
The construction equipment aftermarket has seen:

• 40% increase in conversion kit sales since 2018
  
• Development of hybrid electro-hydraulic systems
  
• Growing support from major equipment dealers
  

Final Recommendations

1. Document pre-conversion control performance
   
2. Use factory-approved seal kits during installation
   
3. Retain original components for 90 days post-install
   
4. Consider fleet-wide standardization
   
5. Train maintenance staff on new system architecture
   

As one equipment manager noted, "The conversion paid for itself in six months through reduced downtime alone. We should have done it years earlier." This upgrade represents one of the most cost-effective ways to extend the service life and improve the performance of these reliable excavators.