Recommissioning the Scat Trak 520V and Restoring Compact Loader Performance

[MikePhua]

The Scat Trak Legacy and the 520V’s Role
Scat Trak was a compact equipment manufacturer known for its rugged skid steers and mini-excavators during the 1980s and 1990s. Though the brand was eventually absorbed into larger corporate entities, its machines—especially the 520V—remain in service across farms, construction sites, and rental fleets. The 520V was a vertical-lift skid steer loader designed for higher reach and better stability when handling pallets, mulch, gravel, or demolition debris.
With an operating weight around 6,000 lbs and a rated lift capacity near 1,700 lbs, the 520V was powered by a diesel engine (often Perkins or Kubota) and featured a mechanical control system with pilot-operated hydraulics. Its simplicity made it a favorite among owner-operators who valued serviceability over electronics.
Challenges of Recommissioning Older Equipment
Bringing a dormant 520V back into service requires a methodical approach. Machines that have sat idle for years often suffer from:

• Dry seals and cracked hoses
  
• Contaminated or evaporated fluids
  
• Corroded electrical terminals
  
• Stuck linkages and seized pins
  
• Fuel system varnish or microbial growth
  
• Battery failure and starter degradation
  

Terminology notes:

• Recommissioning: The process of restoring a machine to operational status after extended disuse.
  
• Hydraulic Purge: Flushing old fluid and air from the hydraulic system to restore pressure and responsiveness.
  
• Fuel Varnish: Sticky residue left by evaporated diesel, which clogs injectors and filters.
  
• Pilot Controls: Low-pressure hydraulic circuits that actuate main valves, offering smoother operation.
  
• Lift Arm Lockout: A mechanical or hydraulic safety feature that prevents arm movement during service.
  

Step-by-Step Restoration Strategy
To safely recommission a Scat Trak 520V:

• Inspect Structural Integrity
  Check the loader arms, frame welds, and bucket mounts for cracks or fatigue. Look for signs of rust near pivot points and under the cab.
  
• Drain and Replace Fluids
  Hydraulic fluid, engine oil, coolant, and fuel should be replaced. Flush the hydraulic tank and clean the suction screen.
  
• Replace Filters
  Install new hydraulic, fuel, oil, and air filters. Use OEM or high-quality aftermarket parts to ensure compatibility.
  
• Test Battery and Electrical System
  Install a fresh battery and inspect wiring harnesses for rodent damage or corrosion. Clean all ground points and fuse terminals.
  
• Purge Fuel System
  Drain old diesel, clean the tank, and replace fuel lines if brittle. Bleed the system to remove air before attempting startup.
  
• Grease All Fittings
  Use high-pressure grease on loader arm pins, tilt cylinders, and wheel bearings. Free up any seized zerks.
  
• Check Tire Condition and Pressure
  Inspect for dry rot, sidewall cracking, and flat spots. Replace if tread is compromised.
  
• Test Hydraulic Functionality
  Start the engine and cycle all loader functions slowly. Listen for pump whine or valve chatter. If sluggish, test system pressure and flow.
  

In one case, a landscaping crew in Michigan recommissioned a 520V that had sat in a barn for eight years. After flushing the hydraulics and replacing the fuel pump, the machine returned to full service and was used to load mulch and stone for seasonal contracts.
Common Issues and Field Solutions
Even after startup, older 520Vs may exhibit:

• Hydraulic Drift
  Loader arms or bucket slowly drop under load. Caused by worn cylinder seals or valve leakage.
  
• Starter Lag
  Engine cranks slowly due to weak solenoid or corroded cables. Replace starter or clean terminals.
  
• Control Stiffness
  Joysticks or foot pedals resist movement. Lubricate linkages and inspect pilot lines for blockage.
  
• Cooling System Weakness
  Overheating during extended use. Flush radiator, replace thermostat, and check fan belt tension.
  
• Fuel Delivery Hesitation
  Engine surges or stalls. Replace injectors or clean the injection pump if varnish persists.
  

Recommended upgrades:

• Install a spin-on hydraulic filter conversion kit for easier maintenance
  
• Add LED work lights for improved visibility
  
• Retrofit with a seat switch and arm lockout for safety compliance
  
• Use synthetic hydraulic fluid for better cold-weather performance
  
• Add a battery disconnect switch to prevent parasitic drain during storage
  

Operator Tips and Maintenance Practices
To keep a recommissioned 520V running smoothly:

• Warm up hydraulics before heavy lifting
  
• Avoid full-throttle operation until system pressure stabilizes
  
• Grease pivot points weekly
  
• Change engine oil every 100 hours
  
• Inspect hydraulic hoses quarterly
  
• Store indoors or under cover to prevent UV damage
  

Operators should be trained to recognize early signs of wear, such as loader arm bounce, control lag, or fluid discoloration. A daily walkaround inspection can prevent costly failures and extend machine life.
Conclusion
Recommissioning a Scat Trak 520V is a rewarding process that blends mechanical intuition with practical restoration. These machines, though no longer in production, continue to serve reliably when treated with care and upgraded thoughtfully. Whether clearing brush, moving aggregate, or grading driveways, a well-restored 520V proves that durability and simplicity still have a place in modern job sites. With proper attention, these compact loaders can return from retirement and deliver years of dependable service.