Hyundai HL770-9S Hydraulic Gear Pump 31LB-40500 | 31FT-01400 31FT-01300 Loader Parts

The 31LB-40500 series high-pressure gear pumps from Chengyuan Hydraulic are premium-grade replacements specifically engineered for the Hyundai HL770-9S wheel loader. As the heart of the loader’s steering and work hydraulic systems, these pumps are fully compatible with OEM specifications 31FT-01400 and 31FT-01300. Constructed with reinforced cast-iron bodies and high-hardness gears, our pumps are built to withstand the intense pressure spikes of heavy loading cycles. Each unit undergoes 100% simulated full-load performance testing to ensure flow and pressure curves match the original Hyundai standards, guaranteeing 100% original-place interchangeability.

Technical Specifications :

• Part Number (P/N): 31LB-40500 / 31FT-01400 / 31FT-01300

• Compatible Model: Hyundai HL770-9S Wheel Loader

• Pump Type: High-Pressure Tandem/Triple Gear Pump

• Max Operating Pressure: 250 bar (25 MPa)

• Rated Speed: 2200 – 2500 rpm

• Displacement: Calibrated to match steering, work, and pilot circuits

• Housing Material: High-strength Ductile Iron for shock resistance

• Drive Shaft: Standard Hyundai spline for vibration-free high-torque transfer

• Sealing Elements: Premium FKM (Viton) seals for superior heat and shear resistance

Key Technical Advantages:

• Reinforced Anti-Shock Housing: Specifically designed for the rugged environments of mines and docks, our pump bodies feature thickened walls and high-grade ductile iron. This significantly reduces fatigue cracking under high-pressure cycling compared to standard aluminum alternatives.

• Axial Clearance Compensation: The floating side plates utilize a pressure-balanced design that automatically adjusts clearances based on system pressure. This ensures that even after long-term service, the pump maintains over 90% volumetric efficiency, preventing flow drop-off during high-temperature operations.

• Precision-Ground Gear Sets: Manufactured from high-strength alloy steel and vacuum-hardened, our gears are precision-ground to minimize contact fatigue. The optimized profile reduces hydraulic ripples and noise, contributing to a quieter operator environment.

• Micro-Tolerance Interface Matching: All inlet/outlet port distances and mounting flange dimensions are held to micron-level tolerances. This allows for a seamless “drop-in” replacement without modifying any existing hydraulic lines, minimizing machine downtime.

Application Areas:

• Hyundai HL770-9S Loader: Primary power for steering and pilot hydraulic supply.

• Bulk Material Handling: High-frequency lifting and steering in port and yard operations.

• Earthmoving Projects: Heavy-duty loading cycles in large-scale infrastructure construction.

Expert Maintenance Tips:

• Zero Axial Impact Rule: Always use proper puller tools when installing drive couplings. Never strike the pump shaft with a hammer, as axial impact will damage the internal thrust plates and potentially seize the pump.

• Filter Replacement Protocol: When installing a new pump, you must replace both the return and suction filters and clean the hydraulic reservoir. This prevents debris from the previous pump failure from contaminating and damaging the new unit.

• Cold Start Pre-Heating: In cold climates, allow the engine to idle and the pump to circulate without load for 5-10 minutes. Wait until the oil temperature reaches at least $20°C$ before performing heavy lifting to avoid cavitation damage due to high oil viscosity.