Maintaining and Troubleshooting the Mustang 940E Skid Loader

[MikePhua]

The Mustang 940E and Its Place in Compact Equipment History
The Mustang 940E skid loader was part of Mustang Manufacturing’s push into the mid-size compact loader market during the late 1980s and early 1990s. Mustang, originally founded in 1865 as the Owatonna Manufacturing Company, became known for its rugged, straightforward designs and strong dealer support across North America. The 940E was powered by a reliable gasoline or diesel engine depending on configuration, and featured a rated operating capacity of approximately 1,400 lbs, making it suitable for landscaping, light construction, and agricultural tasks.
With a mechanical control layout, chain-driven wheels, and a robust hydraulic system, the 940E was built for simplicity and field serviceability. Thousands of units were sold before Mustang was acquired by Manitou Group, and many 940E loaders remain in use today, especially in rural fleets and restoration circles.
Core Systems and Service Intervals
The 940E’s performance depends on regular attention to its core systems. Key components include:

• Engine
  • Typically equipped with a Ford industrial engine or equivalent
    
  • Oil change every 100 hours
    
  • Spark plug inspection (gas models) every 250 hours
    
  • Air filter replacement every 200 hours or as needed
    
• Hydraulic System
  • Gear-type pump delivering flow to lift and tilt cylinders
    
  • Reservoir capacity around 10 gallons
    
  • Filter replacement every 500 hours
    
  • Fluid change every 1,000 hours or annually
    
• Drive System
  • Chain drive with sprockets and tensioners
    
  • Grease fittings on axle bearings and chain cases
    
  • Chain inspection every 250 hours
    
  • Tension adjustment every 500 hours
    
• Electrical System
  

• 12V battery and starter motor
  
• Analog gauges for oil pressure, temperature, and fuel
  
• Fuse block and wiring harness behind operator seat
  

A technician in Alberta rebuilt a 940E’s chain case after discovering excessive slack and sprocket wear. By replacing the chains and re-shimming the tensioners, he restored smooth travel and reduced drivetrain noise.
Hydraulic Troubleshooting and Valve Behavior
The 940E’s hydraulic system is open-center, meaning fluid flows continuously until diverted by spool valves. Common issues include:

• Slow Lift or Tilt Response
  • Clogged filter or suction screen
    
  • Air in lines due to low fluid level
    
  • Worn pump or internal leakage in control valve
    
• Cylinder Drift
  • Seal failure in lift or tilt cylinders
    
  • Spool valve bypass due to worn O-rings or scoring
    
• Noisy Operation
  

• Cavitation from restricted inlet
  
• Contaminated fluid causing pump chatter
  

Solutions:

• Replace hydraulic filter and inspect fluid clarity
  
• Bleed system by cycling cylinders fully
  
• Rebuild spool valve with new seals and polish spool surfaces
  
• Pressure test pump output (target 2,500–3,000 PSI)
  

A restorer in Chile rebuilt his 940E’s control valve after noticing erratic bucket movement. The internal seals had hardened, and the spool bore showed minor scoring. After honing and resealing, the loader regained precise control.
Electrical and Instrument Panel Diagnostics
The 940E’s electrical system is simple but prone to age-related faults. Common problems include:

• Starter Failure
  • Worn solenoid contacts or weak battery
    
  • Corroded ground strap or loose terminals
    
• Gauge Inaccuracy
  • Faulty sender units or broken wires
    
  • Dirty connectors behind dash panel
    
• Lighting Issues
  

• Blown fuses or cracked housings
  
• Switch wear or relay failure
  

Recommended checks:

• Test battery voltage (12.6V at rest, 13.8–14.4V charging)
  
• Inspect wiring harness for abrasion or rodent damage
  
• Clean fuse block and apply dielectric grease
  
• Replace sender units with OEM or matched aftermarket parts
  

A fleet manager in Texas added LED work lights and a new wiring harness to his 940E. The upgrades improved night visibility and eliminated intermittent gauge readings.
Operator Controls and Mechanical Linkages
The 940E uses mechanical levers for lift and tilt control, with direct linkage to spool valves. Over time, these linkages can wear or bind. Maintenance tips:

• Lubricate pivot points and bushings monthly
  
• Adjust linkage rods for full valve travel
  
• Replace worn clevis pins and bushings
  
• Inspect foot pedals and throttle cable for smooth movement
  

A technician in Ontario fabricated new linkage rods from stainless steel after the originals bent during cold-weather operation. The improved rigidity enhanced control response and reduced slop in the levers.
Conclusion and Recommendations
The Mustang 940E skid loader remains a capable and serviceable machine for compact work. With mechanical simplicity and durable components, it offers long-term reliability when maintained properly. Restoration and upkeep require attention to hydraulic integrity, chain drive tension, and electrical cleanliness.
Recommendations include:

• Follow service intervals for engine, hydraulics, and drivetrain
  
• Rebuild spool valves and cylinders when control response degrades
  
• Inspect and upgrade wiring harnesses for consistent electrical performance
  
• Maintain mechanical linkages for precise operator control
  
• Document repairs and create a preventive maintenance schedule
  

With care and mechanical discipline, the 940E continues to lift, grade, and haul with the same grit that defined Mustang’s legacy in compact equipment.