AP2D36LV1RS7 AP2D18 Rexroth Uchida Excavator Pump 350 bar

Product Overview

The AP2D18-888-0 and AP2D36LV1RS7 are the 18 cc-class and 36 cc-class core models within the Bosch Rexroth (formerly Uchida) AP2D series of tandem swashplate axial piston pumps. The AP2D series is specifically engineered as the main hydraulic pump for 1–8 ton class mini and compact excavators, featuring an integrated shared cylinder block design that houses two independent variable piston pump sections within a single housing, delivering two flow outputs from the same drive shaft, with optional integrated gear pump for pilot oil supply.

The AP2D series offers multiple displacement options including 12, 14, 18, 21, 25, 28, and 36 cc/rev, fully compatible with mainstream mini excavator models from Bobcat, Yanmar, Kubota, Doosan, Kobelco, Komatsu, CAT, and Hitachi. The series employs a swashplate variable displacement mechanism where pump flow is proportional to drive speed and displacement, with output flow steplessly variable via swashplate angle adjustment.

AP2D Series Core Features: Integrated dual-pump shared cylinder block design, reducing overall installation size by approximately 30% compared to conventional dual-pump combinations; Total Horsepower Control preventing engine bogging under peak loads; Optional integrated pilot gear pump (GSP2 series) with displacement 4.5–22 cm³/rev; Compact lightweight design with high power density; High-strength cast iron housing and hardened internal steel parts for excellent wear resistance and anti-contamination capability.

Model Code Breakdown (for procurement and engineering reference):

AP2D18-888-0:

• AP2D: Rexroth Uchida AP2D series tandem swashplate axial piston pump

• 18: Nominal size, geometric displacement 18 cm³/rev per section (total 2×18 = 36 cm³/rev)

• 888: Control type and port configuration code

• -0: Design variant and batch identifier

AP2D36LV1RS7:

• AP2D: Rexroth Uchida AP2D series tandem swashplate axial piston pump

• 36: Nominal size, geometric displacement 36 cm³/rev per section (total 2×36 = 72 cm³/rev)

• LV: Control type code, L = Total Horsepower Control, V = variable piston pump configuration

• 1: Design series number

• RS: Rotation direction and port configuration code, R = right-hand, S = side port

• 7: Additional configuration identifier

OEM Cross-Reference (for procurement reference):

• AP2D18: CAT 229-3229 / 263-1867; Hyundai 31MH-10010; Kubota RC411-61112 / RC417-61114

• AP2D36LV1RS7: Compatible with Yanmar VIO70-2/VIO70-3A/VIO75-A/VIO75-C; CAT 307C; Hitachi ZX70/ZX75/ZX85

Drop-in Replacement Advantage: Manufactured to exact Rexroth Uchida OEM specifications, these pumps achieve complete drop-in interchangeability with the original AP2D series for SAE 2-bolt or 4-bolt mounting flange, 13T or 15T splined shaft, SAE standard port layout, and Total Horsepower Control module interface. Every pump undergoes 100% simulated load testing prior to shipment, validating 350 bar pressure loading, Total Horsepower Control response, and volumetric efficiency under conditions replicating real-world duty cycles.

Technical Specifications 

Model AP2D18-888-0:

• Model Code: AP2D18-888-0

• Series: Rexroth Uchida AP2D Series (Tandem Swashplate Variable Piston Pump)

• Displacement per Section: 18 cm³/rev

• Total Displacement (Tandem): 36 cm³/rev (2×18)

• Rated Continuous Working Pressure: 24.5 MPa (245 bar / 3550 psi)

• Maximum System Pressure: 35 MPa (350 bar / 5075 psi)

• Maximum Speed: 2600 rpm (3500 rpm per some sources)

• Theoretical Flow at 2600 rpm: 2×46.8 L/min

• Maximum Power: 19 kW

• Maximum Torque: 75.5 N·m

• Control Type: Total Horsepower Control, optional Power Shift

• Mounting Flange: SAE 2-bolt or 4-bolt standard flange

• Shaft: 13T or 15T splined shaft

• Integrated Pilot Gear Pump: Optional GSP2 series, displacement 4.5–22 cm³/rev

• Housing Material: High-strength cast iron, hardened internal steel parts

• Seal Material: NBR (nitrile rubber), Viton high-pressure shaft seal

• Weight: Approx. 19 kg (base pump body, without auxiliary pump)

• Suitable Excavator Tonnage: 3–6 t

• Fluid Cleanliness: ISO 4406 18/15 or better

Model AP2D36LV1RS7:

• Model Code: AP2D36LV1RS7

• Series: Rexroth Uchida AP2D Series (Tandem Swashplate Variable Piston Pump)

• Displacement per Section (Main P1 & P2): 36.0 cm³/rev

• Total Displacement (Tandem): 72 cm³/rev (2×36)

• Pilot Pump Displacement (P3): Approx. 10.0–12.0 cm³/rev (integrated gear pump)

• Rated Continuous Working Pressure: 29.4 MPa (294 bar / 4264 psi)

• Maximum System Pressure: 32.0 MPa (320 bar / 4641 psi)

• Rated Flow: Approx. 80.0 L/min × 2 (@ 2200 rpm)

• Maximum Speed: 2200 rpm (continuous), 3500 rpm (peak)

• Control Type: Total Horsepower Control

• Mounting Flange: SAE 2-bolt or 4-bolt standard flange

• Shaft: 13T or 15T splined shaft (matches Yanmar 4TNV series engine coupling)

• Housing Material: High-strength cast iron, hardened internal steel parts

• Seal Material: NBR (nitrile rubber), Viton high-pressure shaft seal

• Weight: Approx. 45 kg (base pump body, without auxiliary pump)

• Suitable Excavator Tonnage: 6–8 t

• Fluid Cleanliness: ISO 4406 18/15 or better

AP2D Series Displacement Size Reference:

• AP2D12: 2×12 = 24 cm³/rev, max pressure 350 bar, rated speed 3500 rpm, 1.2–2 t, weight approx. 14 kg

• AP2D14: 2×14 = 28 cm³/rev, max pressure 350 bar, rated speed 3500 rpm, 2–3 t

• AP2D18: 2×18 = 36 cm³/rev, max pressure 350 bar, rated speed 3500 rpm, 3–6 t, weight approx. 19 kg

• AP2D21: 2×21 = 42 cm³/rev, max pressure 350 bar, rated speed 3500 rpm, 4–6 t

• AP2D25: 2×25 = 50 cm³/rev, max pressure 350 bar, rated speed 3500 rpm, 5–6 t, weight approx. 27 kg

• AP2D28: 2×28 = 56 cm³/rev, max pressure 350 bar, rated speed 3500 rpm, 5–6 t

• AP2D36: 2×36 = 72 cm³/rev, max pressure 350 bar, rated speed 3500 rpm, 6–8 t, weight approx. 45 kg

Note: Data compiled from Rexroth Uchida AP2D series technical documentation and industry-published technical references.

Key Technical Advantages

1. Integrated Dual-Pump Shared Cylinder Block Design with Compact Installation
The AP2D series employs an integrated shared cylinder block design, housing two independent variable piston pump sections within a single housing and delivering two flow outputs from the same drive shaft. Compared to conventional dual-pump combinations, overall installation dimensions are reduced by approximately 30%, perfectly fitting the extremely compact engine compartments of mini excavators. This design significantly reduces installation space requirements while minimizing piping connection points, leakage risk, and system complexity.

2. Total Horsepower Control with Full Engine Power Utilization
The AP2D series comes standard with Total Horsepower Control. As system pressure rises, the controller automatically reduces pump displacement to maintain pump input power (P×Q) within the engine’s available power range, fully utilizing engine horsepower to increase machine speed and output power. During combined operations (e.g., simultaneous boom lift and swing), this control method automatically balances power distribution between the two pump units, effectively preventing engine bogging and ensuring smooth, precise machine movement.

3. Integrated Pilot Gear Pump with System Expansion Capability
The AP2D series offers optional integrated pilot gear pumps (GSP2 series) with displacement 4.5–22 cm³/rev, providing a stable oil source for the pilot control circuit. The series also supports through drive, allowing mounting of a third pump or pilot pump on the rear of the main pump for single-drive multi-circuit compound systems. The AP2D series supports pressure feedback adjustment for auxiliary pumps, enabling easy connection with hydraulic breakers, augers, grapples, and other attachments without additional control valves.

4. High-Strength Cast-Iron Housing with Precision Rotary Group
The pump body is precision-cast from high-strength cast iron, with internal steel parts hardened for excellent wear resistance, corrosion resistance, and anti-contamination capability, adapting to harsh construction sites filled with dust, mud, and moisture. Pistons and cylinder bores are precision match-ground to micron-level clearances. The valve plate employs precision lapping with optimized pre-compression and pre-decompression angles, maintaining stable volumetric and mechanical efficiency at 350 bar peak pressure. Nine pistons per side (18 total) ensure smooth output flow with low pressure pulsation.

5. Compact Lightweight Design with High Power Density
The AP2D series is renowned for its compact lightweight design. The AP2D18 achieves a total displacement of 36 cm³/rev with a weight of only approximately 19 kg; the AP2D36 achieves 72 cm³/rev with a weight of approximately 45 kg, leading its displacement class in power density. The compact axial dimensions make the AP2D series particularly suitable for mini excavators and other mobile hydraulic applications with strict installation space requirements. The series maintains excellent operating stability even in rocky terrain, heavy-load lifting, and extreme temperature environments.

6. Wide Hydraulic Fluid Compatibility with Long Maintenance Interval
The AP2D series is compatible with ISO VG32 or VG46 anti-wear hydraulic oils, with an operating temperature range of 30–90°C. The seal material is NBR (nitrile rubber), with Viton high-pressure shaft seal, suitable for mineral oil-based hydraulic fluids. The series offers long maintenance intervals with oil change intervals reaching 2000 working hours, effectively reducing machine downtime and operational costs. All products undergo strict factory testing on pressure, flow rate, and leakage before delivery, complying with Bosch Rexroth’s rigorous quality standards.

Application Areas

• Mini Excavators (3–6 t): AP2D18 compatible with Kubota KX91-3, Komatsu PC30/35/45, CAT 303/E303.5, Takeuchi TB125, Kobelco SK55/SK60-8, Hyundai R35

• Compact Excavators (6–8 t): AP2D36 compatible with Hitachi ZX70/ZX75/ZX85, Hyundai R60/R75-7/R80-7, CAT 307C, Kobelco, Yanmar VIO70/VIO75, John Deere, Daewoo

• Compact Loaders: Compact wheel loader hydraulic systems

• Municipal Maintenance Equipment: Small street sweepers, municipal maintenance machinery hydraulic drives

• Agricultural Machinery: Small agricultural excavators, orchard management machinery hydraulic systems

• Landscaping Equipment: Mini excavators, landscaping machinery hydraulic power sources

Expert Maintenance Tips

1. Pre-Start Pump Housing Priming (Mandatory)
Before starting the engine, manually pre-fill the main pump casing with 1.5–2.0 liters of clean hydraulic oil through its highest case drain port. Operating an axial piston pump bone-dry — even for a few seconds — will cause the piston shoes to “weld” to the swashplate instantly, causing irreversible damage. After installation, turn the drive shaft by hand several revolutions to confirm free rotation without binding.

2. Air Bleeding & Initial Startup Procedure
After installation, loosen the air bleed plug on top of the pump housing. Crank the engine with the fuel supply disabled until a steady stream of oil (no bubbles) flows from the port, then retighten. Allow the machine to idle under no load for 10 to 15 minutes to purge any trapped air from the hydraulic loop.

3. System Fluid Decontamination
If replacing a pump that suffered internal mechanical failure, completely drain and clean the hydraulic oil reservoir, flush all circuit lines, and clean the oil cooler. Replace all return and suction filter elements before starting the engine. System fluid cleanliness for the AP2D series must meet ISO 4406 18/15 or better.

4. Total Horsepower Controller Inspection
The AP2D series Total Horsepower Controller should be calibrated according to the engine’s power characteristics during commissioning. The power control setting must ensure that the system does not exceed the engine’s available power at maximum working pressure, preventing engine bogging under heavy load conditions. Inspect the Total Horsepower Control valve setting and sealing condition every 2,000 operating hours.

5. Integrated Pilot Gear Pump Maintenance
If equipped with an integrated pilot gear pump, regularly check that the pilot pump outlet pressure remains stable within the rated range (typically 20–25 bar) and confirm there is no leakage in the pilot circuit. The pilot pump drive gear shares the lubrication circuit with the main pump drive shaft, requiring no additional maintenance. If pilot pressure fluctuation or drop is observed, inspect the pilot pump wear condition and relief valve setting.

6. Hydraulic Fluid Replacement Interval
Replace hydraulic fluid every 2,000 operating hours or every 6 months, whichever comes first. Recommended fluids are ISO VG32 or VG46 anti-wear hydraulic oils. When changing hydraulic fluid, simultaneously replace filter elements and flush the system to ensure no residual contaminants remain. Monitor oil temperature during operation, ensuring it does not exceed 90°C.