421AK00562B ADU041 Hydraulic Piston Pump | Eaton Vickers 420 Series Replacement

Product Overview

The 421AK00562B and 421AK01088B belong to the ADU041/049/062/080 series of open-circuit axial piston pumps—a complete drop-in interchange solution for Eaton Vickers 420 series hydraulic pumps. Covering displacements from 41 cc to 80 cc, these pumps deliver continuous pressure ratings up to 280 bar (ADU080 rated at 210 bar) and maximum speeds reaching 3600 rpm in intermittent duty. Featuring a swashplate variable displacement design with a standard pressure-flow compensator incorporating an LS port, the mounting flange, spline shaft, and port layout are dimensionally identical to the original Eaton pump, enabling direct bolt-on installation without machine modification.

Every pump undergoes 100% simulated operating-condition testing before shipment, including rated pressure hold, flow characteristic verification, and control response validation—ensuring immediate reliability upon installation.

Technical Specifications 

Model Identification:

• 421AK00562B — Corresponds to ADU041, displacement 41.0 cc/rev (2.50 in³/rev)

• 421AK01088B — Corresponds to ADU062, displacement 62.3 cc/rev (3.80 in³/rev); full model code ADU062R05AB10A2824000A2AB10CD0B

Displacement Range (Full Series):

• ADU041: 41.0 cc/rev (2.50 in³/rev)

• ADU049: 49.2 cc/rev (3.00 in³/rev)

• ADU062: 62.3 cc/rev (3.80 in³/rev)

• ADU080: 80.0 cc/rev (4.88 in³/rev)

Pressure Ratings:

• ADU041 / ADU049 / ADU062 continuous: 280 bar (4060 psi)

• ADU080 continuous: 210 bar (3050 psi)

• Peak pressure: 320 bar (ADU041/049/062); 230 bar (ADU080)

• Maximum intermittent: 350 bar (4600 psi)

Speed Range:

• Minimum speed: 600 rpm

• Maximum speed: 3600 rpm (ADU041 at 2 bar absolute inlet)

• Rated operating speed: 2650 rpm (ADU041/049), 2600 rpm (ADU062), 2500 rpm (ADU080)

• Standby speed: 2950 rpm (ADU041/049), 2800 rpm (ADU062/080)

Control Options:

• Standard: Pressure-flow compensator with LS port

• Optional: Pressure compensator, torque control, remote pressure control (RPC), electronic displacement control (EDC), EH inverse proportional pressure control (IPPC)

Structural Parameters:

• Pump type: Open-circuit axial piston variable displacement

• Mounting flange: SAE 2-bolt B (select models available with 2/4-bolt C)

• Shaft options: 0.875″ keyed / 16/32 13T splined / 1″ keyed / 1.25″ keyed (model-dependent)

• Rotation: Right-hand (CW) or left-hand (CCW)

• Port position: Rear or side

• Weight: 22.9 kg (ADU041/049, single seal); 23.8 kg (ADU062); 24.2 kg (ADU080)

Key Technical Advantages

1. True Drop-in Interchangeability

The ADU041/049/062/080 series maintains 1:1 dimensional compatibility with Eaton Vickers 420 series pumps in mounting flange, drive shaft spline, suction/pressure port locations, and control valve interface. No machine modification is required—direct bolt-on replacement restores equipment operation immediately.

2. High Volumetric Efficiency Rotating Group

Precision-lapped piston-cylinder interfaces and an optimized valve plate design, supported by reinforced bearings, maintain stable volumetric efficiency at 280 bar continuous duty. Bearing B10 life reaches 103,650 hours at 140 bar (ADU041) and maintains 17,150 hours at 210 bar.

3. Load-Sensing Control Reduces Energy Consumption

The standard pressure-flow compensator with LS port enables automatic displacement adjustment based on load demand, maintaining approximately 10 bar (150 psi) standby pressure to reduce heat generation and fuel consumption.

4. Low-Noise Compact Architecture

The one-piece pump housing eliminates leak points and simplifies maintenance. The compact rotating group delivers high power density within constrained engine compartments—25% fewer components than traditional multi-piece housing pumps.

5. Versatile Control Configuration

Beyond standard pressure-flow compensation, options include torque control, remote pressure control (RPC), electronic displacement control (EDC), EH inverse proportional pressure control (IPPC), and electronic de-stroke (cold start) valves to match diverse mobile machinery requirements.

Application Areas

• Agricultural tractors and combine harvesters

• Wheel loaders and backhoe loaders

• Compact wheeled excavators

• Telescopic handlers and rough-terrain forklifts

• Road rollers, pavers, and other road construction equipment

• Sanitation vehicles and mobile engineering vehicles

• Open-loop hydraulic systems across diverse mobile machinery

Expert Maintenance Tips

1. Pre-Installation Inspection

Verify that the new pump’s rotation direction matches the original (viewed from shaft end). The 421AK00562B is configured for right-hand (CW) rotation. Ensure drive shaft-to-coupling concentricity within 0.05 mm to prevent premature seal failure from radial loads.

2. Hydraulic Oil Requirements

Use ISO VG46 anti-wear hydraulic oil with cleanliness level no lower than ISO 4406 18/16/13. Flush the system thoroughly before first operation to eliminate residual metallic particles.

3. LS Line Connection

Ensure the load-sense (LS) port line is securely connected without leakage or blockage. LS line leakage prevents proper load signal response, causing sluggish system operation or abnormal pressure rise.

4. Start-Up Procedure

Fill the pump housing with clean hydraulic oil before first start. Run at low speed (600–800 rpm) unloaded for 5–10 minutes to purge air, then gradually increase to working pressure.

5. Routine Maintenance

Replace hydraulic oil filters every 2,000 operating hours or annually. In dusty environments, shorten filter replacement intervals to 1,000 hours. Periodically inspect the case drain line for obstruction—case drain back pressure must not exceed 0.5 bar.