TB 035 Excavator Pilot Control Valve Solenoid Issues and Solutions

[MikePhua]

The TB 035 excavator is a compact and versatile machine commonly used in confined spaces for various digging and lifting tasks. However, operators may encounter issues related to the pilot control valve solenoid, which can result in sluggish or unresponsive hydraulic actions. This article discusses the common causes of solenoid failures in the TB 035 excavator and provides troubleshooting steps and solutions.
Common Issues and Troubleshooting

1. Pilot Control Valve Solenoid Failure
   • Symptoms: Some hydraulic functions do not respond properly, especially those controlled by the pilot system. The controls may become slow or completely unresponsive.
     
   • Possible Causes: Electrical circuit failure, solenoid coil damage, or disruption of the control signal to the solenoid.
     
   • Solutions: Check the electrical connections to the solenoid, ensuring that the power and signal lines are properly connected and not loose. Use a multimeter to check the resistance of the solenoid coil. If the resistance reads either infinite or near zero, the coil may be damaged and should be replaced. Inspect the solenoid’s circuit board and control system for any short circuits or electrical faults.
     
2. Slow Response from the Solenoid
   • Symptoms: The hydraulic actions are slow or inconsistent, with delayed movement or erratic operation.
     
   • Possible Causes: Sticking solenoid valve components, oil contamination, or inaccurate control system signals.
     
   • Solutions: Disassemble the solenoid valve and check for dirt or debris blocking the valve. Clean the solenoid valve components, including the valve spool and seat. If the hydraulic oil is contaminated, replace it and clean the oil filters.
     
3. Solenoid Coil Power Issues
   • Symptoms: The solenoid fails to activate or does not hold in the correct position.
     
   • Possible Causes: Insufficient power supply to the solenoid coil or issues with the control signal.
     
   • Solutions: Verify that the solenoid is receiving the correct power voltage. Use a multimeter to measure the current flowing through the solenoid. Ensure the current matches the solenoid’s specifications. If there is insufficient current or voltage instability, it may be due to a faulty power source or wiring. Repair the power supply or replace any faulty wiring components.
     
4. Control System Malfunction
   • Symptoms: Hydraulic system fails to respond to control inputs, or the response is too slow.
     
   • Possible Causes: The excavator’s control system may have a malfunction, preventing the correct signal from reaching the solenoid.
     
   • Solutions: Inspect the control system and sensors to ensure that the control signal is being transmitted correctly. Check the circuit board and wiring for any loose connections or damage. Repair or replace any damaged components to restore proper functionality.
     

Maintenance and Preventive Tips

1. Regular Solenoid and Electrical Checks
   Periodically inspect the solenoid’s electrical connections and check the condition of the solenoid coil. Clean the solenoid and remove any contaminants or debris that may affect its performance. Ensure the electrical system is free from short circuits or wiring issues.
   
2. Regular Hydraulic Oil Changes
   Keep the hydraulic oil clean and free from contaminants. Regularly check the oil quality and replace the hydraulic oil as needed. Also, clean or replace the hydraulic oil filters to maintain the hydraulic system in optimal condition.
   
3. Inspect Control Systems and Sensors
   Periodically inspect the hydraulic control system and related sensors to ensure accurate signal transmission. Maintain the electrical control systems to prevent any malfunctions that could affect the solenoid’s operation.
   
4. Timely Repair and Component Replacement
   When issues with the solenoid or hydraulic system arise, address them promptly to prevent more serious system failures. Ignoring small problems can lead to more extensive repairs and longer downtime.
   

Conclusion
Solenoid issues in the TB 035 excavator’s pilot control valve can lead to unresponsive hydraulic functions and poor machine performance. By regularly checking the solenoid, electrical system, and hydraulic oil, and addressing any faults quickly, operators can prevent these problems. Proper maintenance and timely repairs will extend the life of the equipment, ensuring reliable and efficient operation.