FRL074 FRR090 Danfoss Series 45 Piston Pump 310 bar

Product Overview

The FRL074B, FRL090C, FRR074B, and FRR090C are core models within the Danfoss (formerly Sauer Danfoss) Series 45 F Frame open-circuit axial piston variable displacement pumps. The Series 45 platform is Danfoss’s flagship product family in mobile hydraulics, spanning displacements from 25 to 147 cm³/rev, with continuous working pressures up to 310 bar, peak pressure of 400 bar, and maximum speeds up to 3600 rpm, widely deployed in construction machinery, agricultural equipment, material handling equipment, and industrial hydraulic systems.

The Series 45 is renowned for its compact lightweight design, flexible integrated control options, and excellent power density, with extensive field-proven applications in wheel loaders, forklifts, excavators, and telehandlers. The F Frame covers displacements from 74 to 90 cm³/rev, offering both American SAE and European ISO mounting and shaft configurations.

Model Code Breakdown (for procurement and engineering reference):

Using FRL074BLS2520NNN3K4N2A1NNNNNNNNNN as example:

• FRL074B: F Frame, L = left-hand rotation (counterclockwise, viewed from shaft end), 074B = nominal size, geometric displacement 74 cm³/rev

• LS: Load Sensing control — automatically adjusts pump displacement by sensing the pressure differential (Δp) across a throttle valve for on-demand flow delivery

• 25: Pressure compensator (PC) setting code, corresponding to 250 bar

• 20: LS stand-by differential pressure setting of 20 bar

• NNN: Control variant and additional function codes

• 3: Design series number

• K4N2A1NNNNNNNNNN: Shaft, port, and mounting configuration codes

Using FRR090CLS2525NNN3S1B2A1NNNNNNNNNN as example:

• FRR090C: F Frame, R = right-hand rotation (clockwise), 090C = nominal size, geometric displacement 90 cm³/rev

• LS: Load Sensing control

• 25: PC setting 250 bar

• 25: LS stand-by differential pressure setting 25 bar

• S1B2: Splined shaft, SAE-B auxiliary mount, radial ports

Key Application Background: The 237-0292 (CAT 928/930G wheel loader hydraulic pump) and 4740367 (John Deere 772 axial piston pump) are both important application examples of the Series 45 F Frame in the construction machinery industry, enabling true drop-in replacement.

Drop-in Replacement Advantage: Manufactured to exact Danfoss OEM specifications, these pumps achieve complete drop-in interchangeability with the original Series 45 F Frame for SAE-C 4-bolt mounting flange, shaft dimensions (ANSI B92.1 splined shaft), SAE main port layout, and LS/PC control module interface. Every pump undergoes 100% simulated load testing prior to shipment, validating 310 bar pressure loading, load sensing response, and volumetric efficiency under conditions replicating real-world duty cycles.

Technical Specifications

FRL074B Series General Specifications:

• Series: Danfoss Series 45 F Frame (Open Circuit, Swashplate Design)

• Nominal Size: 074B

• Geometric Displacement: 74 cm³/rev (4.52 in³/rev)

• Continuous Working Pressure: 310 bar (4495 psi)

• Peak Pressure: 400 bar (5800 psi)

• Continuous Maximum Speed: 2400 rpm

• Maximum Speed: 2800 rpm

• Minimum Speed: 500 rpm

• Theoretical Flow at 2400 rpm: Approx. 178 L/min

• Control Type: LS — Load Sensing, with integrated pressure compensator

• PC Pressure Adjustment Range: 100–280 bar

• LS Differential Pressure Adjustment Range: 10–40 bar

• Rotation: Left-hand (L code, counterclockwise) or right-hand (R code, clockwise)

• Mounting Flange: SAE-C 4-bolt

• Shaft: Straight keyed 1.25 in or ANSI B92.1 splined shaft

• Port Position: Axial or radial ports

• Housing Material: High-strength cast iron

• Seal Material: NBR/Viton, suitable for mineral oil-based hydraulic fluid

• Weight: Approx. 48 kg

Model FRL074BLS2520NNN3K4N2A1 Configuration:

• Model Code: FRL074BLS2520NNN3K4N2A1NNNNNNNNNN

• Control Type: LS — Load Sensing/Pressure Compensated

• PC Setting: 250 bar

• LS Stand-By: 20 bar

• Input Speed: 2400 rpm

• Mounting Flange: SAE-C 4-bolt

• Rotation: Left-hand (counterclockwise)

• Shaft: Straight keyed 1.25 in

• System Pressure: 310 bar

FRL090C Series General Specifications:

• Series: Danfoss Series 45 F Frame (Open Circuit, Swashplate Design)

• Nominal Size: 090C

• Geometric Displacement: 90 cm³/rev (5.49 in³/rev)

• Continuous Working Pressure: 260 bar (3770 psi)

• Peak Pressure: 350 bar (5075 psi)

• Continuous Maximum Speed: 2200 rpm

• Maximum Speed: 2500 rpm

• Minimum Speed: 500 rpm

• Theoretical Flow at 2200 rpm: Approx. 198 L/min

• Control Type: LS — Load Sensing, with integrated pressure compensator

• PC Pressure Adjustment Range: 100–280 bar

• LS Differential Pressure Adjustment Range: 10–40 bar

• Rotation: Left-hand (L code) or right-hand (R code)

• Mounting Flange: SAE-C 4-bolt

• Shaft: Straight keyed 1.25 in or splined shaft

• Housing Material: High-strength cast iron

• Weight: Approx. 52 kg

Model FRL090CLS2520NNN3K4A2A1 Configuration:

• Model Code: FRL090CLS2520NNN3K4A2A1NNNNNNNNNN

• Control Type: LS — Load Sensing/Pressure Compensated

• PC Setting: 250 bar

• LS Stand-By: 20 bar

• Input Speed: 2200 rpm

• Mounting Flange: SAE-C 4-bolt

• Rotation: Left-hand (counterclockwise)

• Shaft: Straight keyed 1.25 in

• System Pressure: 260 bar

FRR074B Series General Specifications:

• Series: Danfoss Series 45 F Frame (Open Circuit, Swashplate Design)

• Nominal Size: 074B

• Geometric Displacement: 74 cm³/rev

• Continuous Working Pressure: 310 bar (4495 psi)

• Peak Pressure: 400 bar (5800 psi)

• Continuous Maximum Speed: 2400 rpm

• Control Type: LS or PC — Load Sensing/Pressure Compensated

• Rotation: Right-hand (R code, clockwise)

• Mounting Flange: SAE-C 4-bolt

• Housing Material: High-strength cast iron

• Weight: Approx. 48 kg

FRR090C Series General Specifications:

• Series: Danfoss Series 45 F Frame (Open Circuit, Swashplate Design)

• Nominal Size: 090C

• Geometric Displacement: 90 cm³/rev

• Continuous Working Pressure: 260 bar (3770 psi)

• Peak Pressure: 350 bar (5075 psi)

• Continuous Maximum Speed: 2200 rpm

• Control Type: LS — Load Sensing

• PC Pressure Adjustment Range: 100–280 bar

• LS Differential Pressure Adjustment Range: 10–40 bar

• Rotation: Right-hand (R code)

• Mounting Flange: SAE-C 4-bolt

• Housing Material: High-strength cast iron

• Weight: Approx. 52 kg

Series 45 F Frame Displacement Size Reference:

• FRR074B: 74 cm³/rev, continuous 310 bar, continuous speed 2400 rpm, theoretical flow 178 L/min

• FRL074B: 74 cm³/rev, continuous 310 bar, continuous speed 2400 rpm, theoretical flow 178 L/min

• FRR090C: 90 cm³/rev, continuous 260 bar, continuous speed 2200 rpm, theoretical flow 198 L/min

• FRL090C: 90 cm³/rev, continuous 260 bar, continuous speed 2200 rpm, theoretical flow 198 L/min

Key Technical Advantages

1. Load Sensing Control with On-Demand Flow
The Series 45 F Frame’s core control method is load sensing (LS) with integrated pressure compensator (PC). The LS controller senses the pressure differential (Δp) across a throttle valve installed in the user line and automatically adjusts pump displacement to maintain constant throttle pressure drop, delivering precise flow on demand. The system delivers only the flow actually required by the actuators, avoiding excess flow being converted to heat through the relief valve for significant energy savings under variable load conditions. PC pressure setting range is 100–280 bar, and LS differential pressure setting range is 10–40 bar. LS stand-by settings (20 bar or 25 bar) can be matched to the system throttle valve characteristics.

2. SAE-C 4-Bolt Mounting Flange with Standardized Interfaces
The entire Series 45 F Frame range uses the SAE-C 4-bolt mounting flange with dimensions per SAE J744 standard. The shaft is an ANSI B92.1 standard splined shaft (t14 12/24dp) or straight keyed 1.25 in. The standardized mounting interface and port layout (axial or radial ports) require no adaptation for replacement, significantly reducing equipment downtime. SAE O-ring port sealing further enhances connection reliability.

3. Compact Lightweight Design with High Power Density
The Series 45 F Frame is renowned for its compact lightweight design, particularly suitable for space-constrained mobile equipment. The FRL074B achieves a theoretical flow of 178 L/min (at 2400 rpm) at 74 cm³/rev; the FRL090C achieves 198 L/min (at 2200 rpm) at 90 cm³/rev, leading its displacement class in power density. The compact axial dimensions make the Series 45 particularly suitable for wheel loaders, forklifts, and other mobile hydraulic applications with strict installation space requirements.

4. High-Strength Cast-Iron Housing with Wide Temperature Adaptability
The pump body is precision-cast from high-strength cast iron, with the material’s damping characteristics effectively suppressing structural vibration and fluid-borne noise. The Series 45 has been designed to rigorous standards, proven in both laboratory and field, with long service life and significantly fewer parts. No gasketed joints eliminate external leakage risk, and robust input shaft bearings handle large external shaft loads.

5. Integrated Gauge Ports for System Monitoring
The Series 45 is equipped with integrated gauge ports for monitoring operating conditions. Operators can connect pressure gauges through these ports to monitor pump outlet pressure, load sensing pressure, and other key parameters in real time, facilitating system commissioning and troubleshooting. This design provides maintenance personnel with convenient system status monitoring capabilities.

6. Through Drive and Modular System Expansion
The Series 45 supports through drive, allowing direct mounting of subsequent pumps of same or smaller size on the rear of the main pump for single-motor multi-pump compound hydraulic systems. Modular control designs enable field conversion and upgrade, with standardized mounting interfaces requiring no adaptation for replacement. The full range offers a variety of mounting flanges, shafts, and porting options for ease of installation.

Application Areas

• Wheel Loaders: CAT 928/930G wheel loader hydraulic pumps (237-0292 drop-in replacement)

• Agricultural Machinery: John Deere 772 axial piston pumps (4740367 drop-in replacement)

• Forklifts: Lift, tilt, and attachment hydraulic systems

• Telehandlers: Boom extend and lift hydraulic circuits

• Excavators: Medium excavator hydraulic systems

• Material Handling: Reach stackers, container handler hydraulic systems

• Industrial Hydraulic Power Units: Small to medium hydraulic power units, central oil supply systems

• Road Machinery: Road roller and paver hydraulic drive systems

Expert Maintenance Tips

1. Hydraulic Fluid Cleanliness
The Series 45 F Frame LS control spool operates with extremely tight clearances and is highly sensitive to particulate contamination. System fluid cleanliness must meet ISO 4406 18/15/12 or better. Install a 10 μm absolute-rated filter element at the pump inlet. Replace elements at 500 hours after first commissioning, then every 1,000 operating hours or 6 months, whichever comes first. Contamination control is the primary condition for ensuring long-term stable LS controller operation.

2. LS Controller Commissioning and Differential Pressure Setting
The LS controller has a PC pressure setting range of 100–280 bar and an LS differential pressure setting range of 10–40 bar. The LS stand-by differential pressure setting (20 bar or 25 bar) must be matched to the system throttle valve characteristics. Danfoss technical literature recommends a 20 bar LS setting as a starting point for all new applications; for fan-drive systems and systems with motors, the LS setting should be no less than 15 bar to enhance system stability. Adjust only with the system at zero load. Rotate the adjustment screw slowly and verify stable pressure gauge readings before proceeding.

3. Case Drain Line Requirements
The case drain line must return directly to the reservoir. Maximum permissible back pressure is 2 bar (0.2 MPa). The drain outlet must terminate below oil level at all times to prevent air ingestion. The drain line diameter must not be smaller than the pump case drain port size. For “shaft-up” vertical mounting positions, filling and air bleeding must be performed completely.

4. Pre-Start Priming and Air Bleeding
Before first start, fill the pump housing with clean hydraulic fluid through the case drain port. After installation, turn the drive shaft by hand several revolutions to confirm free rotation without binding. Position the control at neutral (zero displacement) and run at low speed for 5–10 minutes. Verify continuous bubble-free flow from the case drain. Only then apply load.

5. Splined Shaft and Coupling Maintenance
The F Frame uses ANSI B92.1 standard splined shafts (t14 12/24dp) or straight keyed 1.25 in. Ensure drive shaft alignment during installation, employing a flexible coupling. Apply appropriate grease to the spline or keyed connection to prevent fretting wear. Inspect coupling alignment and shaft wear at 500 hours after first commissioning, then recheck every 2,000 operating hours.

6. Integrated Gauge Port Usage
The Series 45 F Frame is equipped with integrated gauge ports for convenient system status monitoring. During system commissioning, measure pump outlet pressure and LS pressure through these ports to confirm pressure settings match design values. If abnormal pressure fluctuations occur during operation, the gauge ports can be used to quickly diagnose fault locations. For long-term monitoring, ensure gauge port sealing caps are tightened to prevent dust and moisture ingress.