Bobcat T140 Left Track Won’t Turn Forward Until Hydraulic System Warms

[MikePhua]

Overview
The Bobcat T140 compact track loader is a durable and efficient machine widely used for construction, landscaping, and heavy-duty material handling. Some operators experience a common issue where the left track does not move forward until the hydraulic system reaches normal operating temperature. This behavior can impact productivity and maneuverability, especially in colder conditions or initial start-up periods.
Common Causes

• Thick Hydraulic Fluid During Cold Start
  When hydraulic fluid is cold, its viscosity increases, making it harder to flow through valves and lines. This restricts hydraulic motor performance temporarily, resulting in one track not moving forward.
  
• Hydraulic Pump or Valve Internal Leakage
  Worn or leaking hydraulic pumps, relief valves, or directional control valves may delay pressure build-up on the affected track motor during cold starts, causing delayed movement until system warms.
  
• Hydraulic Motor Stiffness
  The sealed hydraulic motors on the tracks may face increased internal resistance at low temperatures or after inactivity. This added friction reduces initial responsiveness.
  
• Flow Divider or Track Control Valve Malfunction
  The flow divider valve or track steering valve that distributes hydraulic fluid may malfunction or stick when cold, causing uneven flow between tracks.
  

Diagnostic and Troubleshooting

• Check Hydraulic Fluid Condition and Level
  Use manufacturer-recommended fluids with proper viscosity for ambient temperature ranges. Low or contaminated fluid exacerbates cold start issues.
  
• Inspect Track Hydraulic Lines and Connections
  Look for leaks, kinks, or blockages restricting fluid flow primarily to the affected track circuit.
  
• Test Hydraulic Pump Pressure and Flow
  Measure system pressure during cold and warm operating conditions to identify slow pressure build-up or leaks.
  
• Evaluate Valve Operation
  Inspect and clean track directional control valves and flow dividers; replace defective components.
  
• Monitor Temperature Impact
  Observe system response as the machine warms. Operating hydraulic fluid heaters or summer-grade oils might improve start-up performance.
  

Maintenance Suggestions

• Use hydraulic fluids specified for the coldest expected temperatures to maintain fluidity.
  
• Perform routine hydraulic system flushes and filter replacements to prevent contamination and sludge buildup.
  
• Lubricate and service control linkages and valves regularly.
  
• Allow machine warm-up time in cold conditions before heavy operation.
  

User Experiences
Some operators report needing to “crawl” to warm the hydraulic system before the left track functions fully forward. After system warm-up, movement smooths out, and no further delay occurs. Others found that replacing old fluid with correct viscosity oil substantially reduced cold start sluggishness. Track valve cleaning has also resolved similar issues.
Terminology

• Viscosity: Fluid’s resistance to flow; higher viscosity means thicker fluid.
  
• Flow Divider: Valve splitting hydraulic flow equally to track motors to ensure balanced movement.
  
• Directional Control Valve: Valve that directs hydraulic flow to actuators like motors and cylinders.
  
• Hydraulic Motor: Device converting hydraulic fluid pressure into mechanical rotational force to drive tracks.
  
• Cold Start: Initial machine operation period at low ambient temperature when systems have not warmed.
  

Summary
The Bobcat T140’s left track failure to move forward until the hydraulic system warms is commonly due to cold thick hydraulic fluid, worn valves, or pump inefficiencies. Ensuring correct fluid specifications, maintaining hydraulic components, and allowing warm-up improves machine reliability and operator confidence. Addressing these issues promptly preserves the machine’s full-functioning capability in variable temperature environments.