Product Overview
The 42R28DANNA10B3G3F3N3434BNNDAANNN is a Sauer-Danfoss (now part of Danfoss Group) Series 42 swashplate-type axial piston variable displacement pump with a displacement of 28 cm³, belonging to the Series 42 medium-power closed-circuit family. This series covers four displacement sizes — 42R28, 42R32, 42R41, and 42R51 — featuring a cradle swashplate design with hydraulic servo control cylinder, purpose-built for medium-to-high load mobile hydrostatic transmission systems.
The “R” suffix indicates right-hand (clockwise) rotation, and the trailing “D” denotes Electric Displacement Control (EDC). The pump features an SAE standard mounting flange with flexible auxiliary mounting pads for tandem pump configurations. Manufactured to original Sauer-Danfoss specifications with guaranteed drop-in interchangeability, this pump directly replaces the OEM 42R28 without modification to mounting interfaces or hydraulic plumbing. Every unit undergoes 100% simulated working-condition dyno testing prior to shipment, including rated pressure cycling, control response verification, and leakage inspection, ensuring volumetric efficiency, pressure stability, and dynamic response meet OEM-equivalent standards.
Technical Specifications
Model: 42R28DANNA10B3G3F3N3434BNNDAANNN
OEM Material #: 4282755
Series: Sauer-Danfoss Series 42 (42R/42L)
Type: Swashplate axial piston variable displacement pump (closed circuit)
Displacement: 28 cm³/rev (1.71 in³/rev)
Rated Working Pressure: 385 bar (5,584 psi)
Maximum Pressure: 415 bar (6,019 psi)
Minimum Speed: 500 rpm
Rated Speed at Max. Displacement: 3,400 rpm
Maximum Speed at Max. Displacement: 3,750 rpm
Control Type: Electric Displacement Control (EDC); optional MDC / FNR / NFPH / NFPE / HC-EDC
Rotation: Clockwise (R = right-hand, viewed from shaft end)
Mounting Flange: SAE standard flange
Case Pressure Rated: 3.4 bar (50 psi)
Case Pressure Max. (Cold Start): 10.5 bar (150 psi)
Weight: Approx. 34.5 kg (76 lb)
Charge Pump: Integrated
Filtration: Suction or charge pressure filtration
Hydraulic Fluid: Mineral-based hydraulic oil (ISO VG 32–68)
Key Technical Advantages
1. Cradle Swashplate Design with Hydraulic Servo Control
Series 42 pumps utilize the proven cradle swashplate design, with the swashplate driven by a hydraulic servo control cylinder for stepless displacement adjustment. The connection between the servo cylinder and swashplate is optimized to ensure precise displacement response and stable control characteristics across the full displacement range. A stable hydrodynamic lubrication film forms between the swashplate and slippers, effectively reducing friction losses and wear while extending the service life of the rotary group.
2. High Pressure Capability with Compact Lightweight Design
The pump operates at a rated working pressure of 385 bar and a peak pressure of 415 bar, delivering exceptional power density in the 28 cm³ displacement class. The housing is cast from high-strength iron with optimized structural design, resulting in a total pump weight of approximately 34.5 kg — an excellent power-to-weight ratio for its displacement class. The compact axial dimensions make it particularly suitable for space-constrained mobile machinery installations.
3. Integrated Charge Pump and Loop Flushing System
Series 42 pumps feature an integrated charge pump that maintains positive pressure in the closed circuit, preventing cavitation and compensating for system leakage. The charge pump shares the drive shaft with the main pump, requiring no additional mounting space or drive interface. The loop flushing valve effectively removes heat and contaminants from the system, maintaining hydraulic fluid cleanliness and temperature within optimal operating ranges, extending the service life of both the hydraulic fluid and system components.
4. Modular Control Options for Flexible Adaptation
The Series 42 pump offers multiple control module options, including Manual Displacement Control (MDC), Electric Displacement Control (EDC), Non-Feedback Proportional Hydraulic (NFPH), Non-Feedback Proportional Electric (NFPE), and Forward-Neutral-Reverse (FNR) three-position electric control, allowing flexible adaptation to various transmission control schemes. Control modules feature standardized interfaces for easy field replacement and maintenance. This model employs EDC control, providing precise displacement control through connection to the summing link pin within the pump housing.
5. Auxiliary Mounting Pads for Tandem Pump Configurations
All Series 42 pumps feature auxiliary mounting pads (SAE-A or SAE-B) on the housing, allowing auxiliary hydraulic pumps (such as gear pumps or a second piston pump) to be bolted directly to the main pump housing, forming a compact tandem assembly without separate support brackets or additional drive interfaces. This modular design significantly reduces axial installation length, reducing system complexity and installation costs.
Application Areas
The 42R28DANNA10B3G3F3N3434BNNDAANNN is widely used in the following equipment:
Vibratory roller propel drive systems (Ingersoll-Rand and other brands)
Medium-tonnage excavator hydraulic systems
Skid steer loader propel circuits
Telescopic handler hydraulic transmissions
Agricultural machinery (tractor hydraulic drive systems)
Municipal street sweepers and snow removal equipment
Turf care equipment and golf course machinery
Material handling equipment
Expert Maintenance Tips
Pre-Installation Checks: Verify that the pump shaft spline matches the drive end configuration before installation. Apply a light coating of grease to the spline surface. Ensure full contact between the mounting flange and the mounting pad. Never force the pump into position by tightening the fixing bolts, as this may cause abnormal bearing preload or housing deformation. Confirm that the rotation direction (R = right-hand, viewed from shaft end) matches the drive end.
Oil Cleanliness Control: Series 42 pumps are sensitive to fluid contamination. System oil cleanliness should be maintained at ISO 4406 level 20/18/15 or better. Suction filters should be rated at 10 μm or finer; charge pressure filters at 10 μm or finer are recommended. Check suction line sealing before first start-up to prevent air ingress.
Case Pressure Management: The case pressure rating is 3.4 bar (50 psi), with a maximum allowable of 10.5 bar (150 psi) during cold start. The case drain line must remain unrestricted and should be routed directly to the reservoir below the oil level to avoid backpressure affecting pump operation. Periodically inspect the drain line for loosening or wear caused by vibration.
EDC Control Module Maintenance: Periodically inspect the electrical displacement control module wiring and connectors for tightness. Control signal lines should be routed away from high-voltage ignition lines and other electromagnetic interference sources. If sluggish displacement response or system oscillation is observed, first inspect the control module electrical connections and signal inputs.
Start-Up and Break-In: During initial start-up, operate at low speed and low pressure for 10–15 minutes to purge air from the system and check all connections for leakage. Fill the pump case with clean hydraulic oil through the case drain port before starting to prevent dry-start damage to the rotary group. Ensure the suction line is filled with hydraulic fluid before charge pump start-up.
