Product Overview
The 421AK00593C is a variable-displacement, open-circuit axial piston pump from the Eaton Vickers 420/X20 series, now manufactured and supported under the Danfoss Power Solutions portfolio. With a nominal displacement of 41 cc/rev (2.50 in³/rev) and a rated pressure of 280 bar, this pump is engineered for mobile hydraulic systems where compact packaging, high power density, and precise control response are non-negotiable.
Every 421AK00593C unit we supply is built to original Eaton drawing tolerances. Mounting flange geometry (SAE B 2-bolt), spline specification (13-tooth, 16/32), port layout, and compensator control logic are dimensionally identical to the genuine article — delivering true drop-in interchangeability without hose or bracket modification. Each pump undergoes 100% simulated load testing across the full pressure range from rated to peak before shipment.
Technical Specifications
Model: 421AK00593C
Series: Eaton Vickers 420 / X20 (ADU)
Pump Type: Open-circuit axial piston, variable displacement, swashplate design
Displacement: 41.0 cc/rev (2.50 in³/rev)
Rated Pressure: 280 bar (4,060 psi)
Peak Pressure: 350 bar (5,000 psi)
Max Input Speed: 3,600 rpm (2,650 rpm @ 1.0 bar absolute inlet)
Min Input Speed: 600 rpm
Control Type: Pressure & Flow Compensator with Load Sense Port (left side)
Pressure Compensator Setting: 275.8 – 282.7 bar
Flow Compensator Setting: 12.41 – 15.17 bar
Mounting Flange: SAE B, 2-bolt (SAE J744-101-2)
Input Shaft: 13-tooth, 16/32 spline, shaft extension 41.1 mm [1.62 in]
Rotation: Right-hand (CW), right-side suction / left-side pressure port
Shaft Seal: Polyacrylate
Housing Material: Cast iron
Max Case Pressure: 350 bar
Continuous Allowable Case Pressure: 320 bar
Weight (reference, same platform): approximately 23.9 kg
Specifications compiled from Eaton Vickers 420 series published engineering data.
Key Technical Advantages
Rigid Swashplate & Extended Bearing Life. The 421AK00593C employs a rigid swashplate architecture that minimizes deflection during displacement changes. Combined with a steel-backed polymer bearing saddle, this distributes bearing loads uniformly and yields a design bearing life exceeding 10,000 hours at rated pressure — a decisive advantage for excavators and loaders operating under continuous variable-duty cycles.
Bimetallic Valve Plate & High Volumetric Efficiency. The bimetallic valve plate (steel substrate with bronze alloy running surface) maintains a stable oil film at high rotational speeds, keeping internal leakage at class-leading low levels. Coupled with precision-lapped piston-to-bore clearances, volumetric efficiency exceeds 95% under rated conditions, reducing system heat generation and parasitic power loss.
Fast Response & Multi-Mode Control Compatibility. The pressure-and-flow compensator responds in approximately 20 ms and supports pressure compensation, flow compensation, and load sensing in configurable combinations. The 0.4375-20 SAE O-ring load sense port (left side) enables low-standby-pressure load sensing circuits, with standby pressure adjustable down to 12.41 bar.
Compact Envelope & Flexible Mounting. A single control piston design constrains the pump width to 146 mm (5.75 in). The SAE B 2-bolt flange and configurable side/end port arrangement accommodate tight engine-bay installations in mobile equipment. The pump supports both side and end mounting orientations, allowing port positioning to match host machine routing.
Application Areas
The 421AK00593C is specified for the following mobile and industrial hydraulic systems:
Construction: Compact excavators (boom/bucket/swing circuits), backhoe loaders, skid-steer loaders
Agriculture: Combine harvester hydraulic drives, sprayer pump systems, tractor auxiliary hydraulics
Municipal Vehicles: Snow removal trucks, refuse compactors, fire apparatus hydraulic power units
Material Handling: Telehandlers, aerial work platforms, crane hydraulic circuits
Industrial: Automated production line power units, high-pressure machine tool actuator circuits
Expert Maintenance Tips
Pre-Installation Checks. Verify that the suction line diameter supports the pump’s self-priming requirement at maximum speed. At 2,650 rpm, the 421AK00593C requires a minimum inlet absolute pressure of 1.0 bar. Use a suction filter rated at 10 μm or finer. The case drain line must return directly to tank with back pressure not exceeding 0.5 bar.
First Start-Up. Fill the pump housing with clean hydraulic oil (ISO VG 32 or 46, cleanliness NAS 8 / ISO 18/16/13) before initial start. Jog the starter 2–3 times to confirm rotation direction (CW). Run unloaded for 5 minutes, then ramp to rated pressure gradually. The pressure compensator is factory-set at 275.8–282.7 bar. If adjustment is required, turn the adjustment screw clockwise in increments not exceeding 1/4 turn, then tighten the locknut.
Routine Maintenance. Inspect case drain flow every 500 hours — a significant increase typically indicates piston/bore wear. Replace suction and return filter elements every 2,000 hours. Maintain oil cleanliness at ISO 18/16/13 or better. Keep oil temperature below 80°C, never exceeding 104°C (220°F). After extended storage, circulate unloaded for 30 minutes before applying load.
