Eaton Vickers 420 421 Series Piston Pump | 421AK00533C | ADU62 421AK00296A

LIC Hydraulic’s Eaton Vickers 420 & 421 Series (ADU Series) axial piston variable displacement pumps are built to withstand the most demanding hydraulic environments. Featuring specific part numbers like 421AK00533C, 421AK00296A, and the ADU62 displacement frame, our pumps provide 100% Drop-in Interchangeability for original equipment. The 420 series is renowned for its 9-piston rotating group and heavy-duty swashplate design, providing low-noise and high-pressure performance. With integrated Load Sensing (LS) and Pressure Compensator (PC) controls, these pumps are the heart of energy-efficient mobile and industrial systems.

Technical Specifications (Quick Reference)

• Series Models: 420, 421, ADU62.

• Displacement: $62\text{ cm}^3\text{/r}$ ($3.78\text{ in}^3\text{/r}$).

• Rated Pressure: $280\text{ bar}$ ($4060\text{ PSI}$).

• Peak Pressure: $320\text{ bar}$ ($4600\text{ PSI}$).

• Control Types: Load Sensing (LS), Pressure Compensator (PC), Remote Controls.

• Max Speed: $2800\text{ RPM}$ at full displacement.

Key Technical Advantages

• Rapid Control Response: The 420 series is designed for dynamic systems, offering lightning-fast swashplate adjustment to match fluctuating flow demands, minimizing pressure spikes.

• High Power Density in a Compact Frame: The shortened pump body allows for easy installation in tight engine compartments or as part of a multi-pump tandem configuration.

• Rugged Durability: Equipped with heavy-duty drive shaft bearings and hardened cylinder block surfaces, the 421AK series excels in harsh mobile environments where dust and vibration are constant.

• Energy Efficiency: The Load Sensing technology ensures the pump only consumes the horsepower required by the load, drastically reducing fuel consumption and oil temperature rise.

Application Areas

• Mobile Machinery: Steering and auxiliary pumps for loaders, excavators, and backhoes.

• Specialty Vehicles: Hydraulic systems for refuse trucks, sweepers, and truck-mounted cranes.

• Agricultural Equipment: High-pressure circuits for tractors and specialized harvesters.

Expert Maintenance Tips

• Case Drain Installation: Always ensure the case drain line is routed directly to the reservoir and is connected to the highest port on the pump body. This prevents air pockets that could cause the shaft seal to overheat.

• LS Tuning: To optimize machine performance, verify the Load Sense differential pressure is correctly set (typically $250\text{–}300\text{ PSI}$). Incorrect settings can lead to “sluggish” hydraulic response or excessive power draw.

• Oil Quality Standard: To protect the precision-lapped 9-piston group, maintain system filtration at ISO 4406 18/16/14 or better. Contamination is the leading cause of internal slippage and reduced volumetric efficiency in the ADU62 series.