R902129756 A4VG180EP4DT1 Rexroth Pump 180cc 400bar Closed Circuit

Product Overview (Applicable to Both R902129756 and R902150691)

The R902129756 (full model: A4VG180EP4DT1/32L-NZD02N001EH-S) and R902150691 (full model: A4VG180EP4DT1/32R-NZD02N001EH-S) are members of the Bosch Rexroth A4VG Series 32 swashplate-type axial piston variable displacement pump family. With a maximum geometric displacement of 180 cm³/rev, these pumps are specifically designed for closed-circuit hydrostatic transmission applications.

The A4VG Series represents Rexroth’s high-performance axial piston pump platform for closed-circuit hydrostatic drives, with displacement sizes ranging from 28 to 250 cm³/rev, widely deployed in large construction machinery, mining equipment, concrete pumps, and marine hydrostatic drive systems. This model is equipped with EP4 electronic-hydraulic proportional control, powered by a 24 VDC supply for stepless displacement adjustment and flow direction reversal—making it an ideal choice for modern electronically controlled hydrostatic drive systems.

Key Difference Between the Two Models:

• R902129756 corresponds to 32L configuration — counterclockwise rotation (viewed from shaft end)

• R902150691 corresponds to 32R configuration — clockwise rotation (viewed from shaft end)

Apart from the rotation direction, both models are identical in displacement, pressure ratings, control type, and all other technical specifications.

Engineered as a premium drop-in replacement for Bosch Rexroth original hydraulic pumps, this unit strictly adheres to Rexroth A4VG Series 32 design standards and manufacturing specifications, ensuring complete interchangeability — mounting flange interfaces, port configurations, and control logic are fully compatible with the original OEM model, requiring zero field modification for direct replacement.

Every unit undergoes 100% simulated duty-cycle testing — full performance curve validation under rated pressure (400 bar), rated speed, and expected operating temperature ranges — guaranteeing volumetric efficiency, response characteristics, and noise levels that meet or exceed Rexroth factory specifications.

Technical Specifications

• Model Code (R902129756): A4VG180EP4DT1/32L-NZD02N001EH-S

• Model Code (R902150691): A4VG180EP4DT1/32R-NZD02N001EH-S

• Material Number (R902129756): R902129756

• Material Number (R902150691): R902150691

• Series: Bosch Rexroth A4VG Series 32, Swashplate Axial Piston Variable Pump

• Maximum Geometric Displacement (Vg max): 180 cm³/rev

• Rated Operating Pressure (Continuous): 400 bar (40 MPa)

• Peak Pressure (Intermittent): 450 bar (45 MPa)

• Maximum Pressure (some variants): 550 bar

• Maximum Speed: 1900 rpm

• Control Type: EP4 — Electronic Proportional Control, 24 VDC supply

• Design Series: Series 32

• Rotation Direction (R902129756): L — Counterclockwise (viewed from shaft end)

• Rotation Direction (R902150691): R — Clockwise (viewed from shaft end)

• Shaft Type: Z — Splined Shaft DIN 5480 (as defined by NZD02N001EH-S model code segment)

• Mounting Flange: SAE Standard Flange Mounting

• Port Configuration: 02 — SAE Working Port Configuration

• Charge Pump: Integrated charge pump, 39.8 cm³/rev displacement, for feed and control oil supply

• Charge Pressure: Approx. 20 bar

• Circuit Type: Closed Circuit

• Compatible Fluids: Mineral oils, water-glycol, synthetic hydraulic fluids

• Fluid Temperature Range: 30°C to 90°C

• Weight: Approx. 95–100 kg

Key Technical Advantages

1. Large Displacement & Superior Power Density

The A4VG180 delivers a maximum geometric displacement of 180 cm³/rev, positioning it among the largest-displacement models in the A4VG Series. Combined with a rated pressure of 400 bar and peak pressure of 450 bar, a single pump delivers immense hydraulic power. This exceptional power density enables equipment manufacturers to achieve both high flow and high pressure within a compact footprint—ideal for large mining machinery and marine hydrostatic drive systems.

2. EP4 Electronic Proportional Control & Precise Modulation

This model is equipped with EP4 (Electronic Proportional Control) regulation. The EP4 controller operates on a 24 VDC supply, enabling stepless displacement modulation via standard mobile controllers. Control current and displacement output follow a precise proportional relationship—typically, approximately 200 mA corresponds to the initial adjustment point, with full displacement achieved at approximately 600 mA. This precise electronic control characteristic makes EP4 particularly suitable for modern mobile machinery requiring CAN bus system integration and intelligent flow management.

3. Closed-Circuit Optimized Architecture & Comprehensive Safety Protection

Internally optimized fluid passages specifically for closed-circuit applications, with an integrated charge pump (39.8 cm³/rev displacement) as standard equipment, providing continuous charge and cooling flow to the closed circuit. Integrated high-pressure relief valves with feed function protect the pump and actuators during system overload events. Adjustable pressure cut-off is standard, effectively preventing system overpressure.

4. Swashplate Through-Zero Reversal & Bumpless Direction Switching

The swashplate angle can smoothly pass through the zero position to achieve bumpless flow direction reversal without the need for directional valves. This characteristic is particularly critical in frequent reversal applications such as vehicle forward/reverse shifting and winch hoist/lower operations—eliminating reversal shocks and significantly improving operating comfort and system longevity.

5. Thru-Drive Capability & System Integration Flexibility

Full-power thru-drive capability supports tandem mounting of additional pumps of the same or smaller nominal size without additional power input. This makes the A4VG180 an ideal core power component for complex hydraulic systems—a single pump can simultaneously drive both travel and working systems, dramatically simplifying system architecture.

6. Complete Drop-In Interchangeability & Standardized Interfaces

Strictly manufactured to original Rexroth A4VG Series 32 micro-metric factory blueprints. SAE standard mounting flanges and port configurations align flawlessly with original factory specifications. R902129756 (32L counterclockwise) and R902150691 (32R clockwise) cover the two primary rotation direction requirements. Field replacement requires zero piping modifications or control logic changes, dramatically minimizing equipment downtime.

Application Areas

• Large Port Ship Cranes — Liebherr LHM-500

• Truck-Mounted Concrete Pumps — Putzmeister K36, M36

• Stationary Concrete Pumps — Putzmeister BSA 1409

• Ultra-Large Mining Excavators

• Hydrostatic Travel Drives — Wheel loaders, mining trucks

• Marine Deck Machinery & Winches

• Large Road Construction Machinery

• Industrial Hydrostatic Transmissions

Expert Maintenance Tips

1. Case Fill & Air Bleeding Before Start-up

Prior to first start-up, fill the pump housing with clean hydraulic fluid through the highest case drain port to ensure complete pre-lubrication of all bearings and rotating components. For closed-circuit systems, ensure charge pump has established adequate charge pressure (typically no less than 20 bar) before start-up. Run at low speed without load for at least 2-3 minutes after start-up, and only apply load after the system is fully purged of air.

2. Rotation Direction Verification

Before installation, confirm the equipment’s rotation direction requirement:

• R902129756 (32L) — Counterclockwise rotation

• R902150691 (32R) — Clockwise rotation

Incorrect rotation selection will result in pump malfunction or damage.

3. EP4 Electronic Control Setting & Calibration

EP4 electronic-hydraulic proportional control settings should be adjusted after the pump reaches operating temperature and the system is fully purged. The relationship between control current and displacement output should be calibrated per Rexroth standard characteristic curves. Use a current source and pressure sensor with accuracy class 0.5 or better for setting verification. Adjust control current slowly while observing system response to avoid abrupt impacts.

4. Fluid Cleanliness Management

A4VG Series pumps are ultra-high-pressure precision hydraulic components highly sensitive to fluid contamination. Maintain system fluid cleanliness at or above the recommended ISO 18/16/13 level. Use full-flow return filters with minimum 10μm absolute rating (β₁₀≥100) and conduct regular fluid sampling analysis (recommended every 500 operating hours).

5. Charge Pressure & System Temperature Monitoring

Charge pressure is a critical parameter for proper pump operation in closed-circuit systems. Regularly verify charge pump outlet pressure (typically set at 20–25 bar) remains within specification. Install continuous oil temperature monitoring to ensure fluid temperature does not exceed 90°C. Charge filters should be replaced periodically to prevent insufficient charge flow due to filter clogging.

6. Scheduled Inspection & Seal Replacement

Perform comprehensive performance testing every 2000 operating hours or annually (whichever comes first), including volumetric efficiency testing, EP4 control response time verification, and case drain leakage assessment. Always use genuine Rexroth service kits (material numbers beginning with R902/R909/R910) when replacing seals, and verify that seal material options are compatible with the system fluid type.