11 hours ago
Hitachi LX70-2 Loader Background
The Hitachi LX70-2 is a compact wheel loader designed for light construction, agricultural, and municipal tasks. Introduced in the late 1990s, it features a hydrostatic transmission powered by a piston-type hydraulic pump, with electric-over-hydraulic control systems. The machine weighs approximately 7,000–8,000 kg and is equipped with a hydraulic motor that drives the transmission, similar to mixer trucks and wheeled excavators.
Hitachi Construction Machinery, founded in 1970, expanded rapidly through the 1990s, offering reliable and electronically enhanced loaders across Asia and North America. The LX70-2 was part of a broader push into compact equipment, with thousands of units sold globally. Its design emphasized maneuverability, visibility, and simplified control logic.
Symptoms of Weak Travel Performance
Operators of the LX70-2 have reported weak travel power in both forward and reverse directions, while all other hydraulic functions remain unaffected. This issue is consistent across all speed ranges and persists even after warm-up. In some cases, the machine was acquired with the problem already present, suggesting long-term degradation rather than sudden failure.
Key Components Involved
Diagnostic Recommendations
In 2016, a contractor in Perth, Australia reported weak travel on his LX70-2. After ruling out electrical faults, he measured pilot pressure and found it below spec. A replacement gear pump resolved the issue, and the loader returned to full performance. The dealer had been unable to diagnose the problem, highlighting the importance of field experience and pressure testing.
Recommendations for Owners
Weak travel in the Hitachi LX70-2 is often caused by low pilot pressure due to gear pump wear. By focusing diagnostics on the pilot circuit and verifying solenoid function, technicians can restore full mobility without unnecessary part replacement. The LX70-2 remains a capable machine, and with proper maintenance, it can continue serving reliably in demanding environments.
The Hitachi LX70-2 is a compact wheel loader designed for light construction, agricultural, and municipal tasks. Introduced in the late 1990s, it features a hydrostatic transmission powered by a piston-type hydraulic pump, with electric-over-hydraulic control systems. The machine weighs approximately 7,000–8,000 kg and is equipped with a hydraulic motor that drives the transmission, similar to mixer trucks and wheeled excavators.
Hitachi Construction Machinery, founded in 1970, expanded rapidly through the 1990s, offering reliable and electronically enhanced loaders across Asia and North America. The LX70-2 was part of a broader push into compact equipment, with thousands of units sold globally. Its design emphasized maneuverability, visibility, and simplified control logic.
Symptoms of Weak Travel Performance
Operators of the LX70-2 have reported weak travel power in both forward and reverse directions, while all other hydraulic functions remain unaffected. This issue is consistent across all speed ranges and persists even after warm-up. In some cases, the machine was acquired with the problem already present, suggesting long-term degradation rather than sudden failure.
Key Components Involved
- Pilot Gear Pump: Supplies low-pressure hydraulic oil to control valves and solenoids. A healthy system should deliver around 500 psi; readings of 300 psi or lower indicate insufficient pilot pressure.
- Travel Control Solenoids: Electrically actuated valves that direct hydraulic flow to the travel motor. If these solenoids fail or receive weak signals, travel power drops.
- Hydraulic Motor: Converts hydraulic energy into mechanical rotation for the transmission. Its performance depends on adequate flow and pressure from the main pump.
- Main Piston Pump: Drives all hydraulic functions, including travel. If the pump is worn or the pilot signal is weak, travel output suffers.
Diagnostic Recommendations
- Measure Pilot Pressure: Use a calibrated gauge to check output at the pilot pump. Readings below 400 psi suggest internal wear or leakage.
- Inspect Solenoids and Wiring: Confirm that travel control solenoids are receiving full voltage and are free of corrosion or damage.
- Check Hydraulic Filters: Clogged filters can restrict flow to the motor, mimicking pump failure.
- Review Transmission Setup: The LX70-2 uses a hydraulic motor-driven transmission. Ensure that the motor is receiving adequate flow and that the drive coupling is intact.
- Pilot Pressure: Low-pressure hydraulic oil used to actuate control valves.
- Solenoid Valve: An electrically controlled valve that directs hydraulic flow.
- Hydrostatic Transmission: A drive system using hydraulic motors instead of mechanical gearboxes.
In 2016, a contractor in Perth, Australia reported weak travel on his LX70-2. After ruling out electrical faults, he measured pilot pressure and found it below spec. A replacement gear pump resolved the issue, and the loader returned to full performance. The dealer had been unable to diagnose the problem, highlighting the importance of field experience and pressure testing.
Recommendations for Owners
- Replace Worn Pilot Pumps: If pressure is low, rebuilding or replacing the gear pump is essential.
- Document Pressure Readings: Keep a log of pilot and main pump pressures for future reference.
- Clean Electrical Contacts: Ensure solenoids receive full voltage by maintaining clean connectors.
- Flush Hydraulic System: After any component failure, flush the system to remove debris and prevent recurrence.
Weak travel in the Hitachi LX70-2 is often caused by low pilot pressure due to gear pump wear. By focusing diagnostics on the pilot circuit and verifying solenoid function, technicians can restore full mobility without unnecessary part replacement. The LX70-2 remains a capable machine, and with proper maintenance, it can continue serving reliably in demanding environments.
