PVD-0B-24P-8G3-4837B Nachi Excavator Piston Pump 24cc 245bar

Product Overview

The PVD-0B-24P-8G3-4837B is a NACHI (Fujikoshi) PVD Series swashplate-type axial variable displacement piston pump designed specifically for mini excavators, featuring a nominal displacement of 24 cm³/rev, maximum working pressure of 24.5 MPa (3553 psi), maximum speed of 2800 rpm, and weight of approximately 13 kg. The pump employs a split-flow dual-circuit design in which a single pump housing integrates two independent piston pump sections, each delivering equal flow to the left and right travel motors — ensuring straight-line travel of the crawler undercarriage without operator correction. This design enables one pump to simultaneously handle two load-sensing control functions, effectively preventing engine lugging under heavy digging loads.

The model features constant horsepower control as standard (optional gear pump feedback enables total horsepower control), dynamically adjusting pump displacement so that total hydraulic system power consumption never exceeds the engine output power curve, fully unleashing engine horsepower for increased machine speed and power output. The “8G3” configuration code corresponds to a gear pump section displacement of 6.4+2.7 cm³/rev, suitable for Kubota U25-3 and U25S 2.5-ton class zero-tail-swing mini excavators.

The PVD series pumps are characterized by very short overall length and compact design, occupying minimal space within the excavator engine compartment. The pump features an SAE B two-bolt mounting flange (centering diameter 101.6 mm) and 13-tooth spline shaft, with internal drainage design that eliminates the need for external drain lines, simplifying system plumbing layout. The pump is fully compatible with Kubota U25-3/U25S (OEM part numbers RB511-61114, RB511-61112) and Bobcat E25/E26/E27Z (OEM part numbers 7209325, 7209326).

The companion model PVD-1B-32P-1165-46650 is a 32 cm³/rev displacement configuration suitable for 2.7–3.5 ton mini excavators, with main pump 32 cm³/r, gear pump 11 cm³/r, rated pressure 21 MPa, peak pressure 24 MPa, and weight approximately 25 kg. Sharing the PVD series platform with the PVD-0B-24P, it maintains the same split-flow design philosophy and constant horsepower control architecture.

Every PVD-0B-24P-8G3-4837B and PVD-1B-32P-1165-46650 undergoes 100% simulated duty-cycle testing prior to shipment — covering pressure holding, flow output, control response, and internal leakage — ensuring complete drop-in interchangeability with original NACHI pumps without installation or plumbing modifications.

Technical Specifications

• Model: PVD-0B-24P-8G3-4837B

• Brand: NACHI (Fujikoshi)

• Series: PVD Series split-flow variable piston pump

• Pump Type: Variable axial piston pump + gear pump section

• Maximum Displacement: 24 cm³/rev (12×2 split configuration)

• Maximum Working Pressure: 24.5 MPa (3553 psi)

• Maximum Speed: 2800 rpm

• Rated Speed: 2600 rpm

• Minimum Speed: 900 rpm

• Direction of Rotation: P (right-hand, clockwise viewed from shaft end)

• Mounting Flange: SAE B two-bolt flange (centering diameter 101.6 mm)

• Shaft Type: 13-tooth spline shaft

• Gear Pump Configuration: 8G3 = 6.4+2.7 cm³/rev gear pump section

• Case Drain: Internal drainage, no drain line required

• Weight: Approx. 13 kg

• Control Type: Constant horsepower control (standard)

• Machine Compatibility: Kubota U25-3/U25S (OEM: RB511-61114/RB511-61112), Bobcat E25/E26/E27Z (OEM: 7209325/7209326)

• Operating Oil Temperature Range: 15–60 ℃

• Fluid Compatibility: Mineral-based hydraulic oil, anti-wear hydraulic oil

PVD Series Same-Family Displacement Reference:

• PVD-00B: Max. 8×2 cm³/rev, 24.5 MPa, max 2800 rpm, weight approx. 9 kg

• PVD-0B: Max. 12×2 cm³/rev, 24.5 MPa, max 2800 rpm, weight approx. 13 kg

• PVD-1B: Max. 17×2 cm³/rev, 24.5 MPa, max 2700 rpm, weight approx. 15 kg

• PVD-2B: Max. 22.5×2 cm³/rev, 24.5 MPa, max 2600 rpm, weight approx. 20 kg

• PVD-3B: Max. 33×2 cm³/rev, 24.5 MPa, max 2400 rpm, weight approx. 27 kg

Companion Model Reference:

• Model: PVD-1B-32P-1165-46650

• Series: PVD Series

• Main Pump Displacement: 32 cm³/rev

• Gear Pump Displacement: 11 cm³/rev

• Rated Pressure: 21 MPa, Peak 24 MPa

• Mounting Flange: SAE B flange (φ101.6 mm), 13-tooth spline shaft

• Weight: Approx. 25 kg

• Compatible Equipment: Hitachi ZX27U/ZX30U/EX35, Kubota U30/U35, Yanmar VIO30/VIO35

Key Technical Advantages

1. Split-Flow Dual-Circuit Design — Guaranteed Straight-Line Travel

The PVD-0B-24P-8G3-4837B employs NACHI’s proprietary split-flow design, integrating two independent piston pump sections within a single housing, each delivering equal flow to left and right travel motors. This design ensures straight-line travel without operator correction on soft ground and slopes, with flow variation between the two travel circuits less than 1%, significantly improving control precision. Compared to dual-pump solutions, this design reduces the number of pump bodies and installation space requirements, offering exceptional installation advantages within the compact engine compartments of mini excavators.

2. Constant Horsepower Control — Intelligent Anti-Stall and Engine Power Utilization

The pump features standard constant horsepower control, dynamically adjusting pump displacement so that total hydraulic system power consumption remains below the engine power output curve. Optional gear pump feedback enables total horsepower control, incorporating gear pump power consumption into the control scope for true intelligent engine power management. Under heavy digging conditions, this control characteristic effectively prevents engine lugging and stalling while fully unleashing engine horsepower for increased machine speed and power output.

3. Compact Structure and Drain-Line-Free Design

The PVD series is renowned for its extremely short overall length, with the PVD-0B-24P-8G3-4837B designed for easy installation within the limited engine compartment of mini excavators. The pump features internal drainage, eliminating the need for external case drain lines, simplifying system plumbing and reducing potential leak points. The SAE B two-bolt mounting flange (centering diameter 101.6 mm) and 13-tooth spline shaft are standard configurations, enabling rapid drop-in interchangeability with original NACHI pumps.

4. High Volumetric Efficiency and Low-Noise Operation

The PVD series employs swashplate axial piston design with optimized rotary group and port plate flow passages. The pump maintains high efficiency in the high-pressure range, with flow variation between ports less than 1%, ensuring stable hydraulic system output. The PVD-1B-32P features a semi-cylindrical swashplate design to reduce flow loss, with slipper, swashplate, and port plate adopting noise-reduction structures, achieving noise levels ≤75 dB(A). Optimized flow path design reduces power loss by 15–20%, with constant horsepower control maximizing engine power utilization.

5. Exceptional Field Interchangeability and Broad Compatibility

The PVD-0B-24P-8G3-4837B features mounting flange, shaft specifications, and port layouts conforming to NACHI PVD Series standards, enabling drop-in interchangeability with other PVD-0B models. The pump is directly compatible with Kubota U25-3/U25S (OEM part numbers RB511-61114/RB511-61112) and Bobcat E25/E26/E27Z (OEM part numbers 7209325/7209326), installing directly without modifying mounting interfaces or plumbing layouts. The companion PVD-1B-32P-1165-46650 shares the PVD series platform with the PVD-0B-24P, providing system integration solutions for different displacement requirements.

Application Areas

• Mini Excavators: Main hydraulic pump for Kubota U25-3, U25S, KX25, U20-5 and other 2–2.5 ton class mini excavators

• Sub-Compact Excavators: Hydraulic power source for Bobcat E25, E26, E27Z and other 2.5–2.7 ton class mini excavators

• Small Construction Machinery: 3-ton class slewing loaders and small crawler drilling machines

• Industrial Hydraulic Power Units: Low-flow high-pressure units, hydraulic fixtures, and test benches

• Special Vehicles: Small sanitation vehicles and agricultural hydraulic systems

The PVD-0B-24P-8G3-4837B is ideally suited for main hydraulic pump replacement on Kubota U25-3/U25S and Bobcat E25/E26/E27Z 2.5–2.7 ton class mini excavators. The PVD-1B-32P-1165-46650 is suitable for Hitachi ZX27U/ZX30U/EX35, Kubota U30/U35, Yanmar VIO30/VIO35 and other 2.7–3.5 ton class mini excavators.

Expert Maintenance Tips

1. Pump Housing Priming and Air Bleeding (Mandatory)

Before starting the engine, the pump casing must be manually filled with clean hydraulic fluid through its highest case drain port until fluid overflows. Operating an axial piston pump dry — even for a few seconds — will score the swashplate, valve plate, and piston slippers, causing immediate total pressure loss and irreversible damage. After filling, loosen the top air bleed port on the pump housing. Crank the engine with the fuel delivery disabled until a steady stream of bubble-free hydraulic oil flows out, then retighten the plug. Allow the machine to idle at low RPM with no load for 10 to 15 minutes to purge any remaining air from the system.

2. Hydraulic System Cleaning and Contamination Control

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. Always replace return and suction filter elements prior to initial engine startup to prevent metal particles and contaminants from the failed pump from entering the new pump and causing secondary damage. The PVD-0B-24P requires fluid cleanliness of NAS Class 9 (ISO 18/16/13) or better, using 10 μm pressure line filters.

3. Pressure Regulator and Relief Valve Verification

Verify that system main relief pressures match factory excavator specifications upon initial testing. Improper relief valve settings can cause sluggish implement speed, circuit overheating, or engine stalling under load. The PVD-0B-24P-8G3-4837B operating pressure setting on Kubota U25-3 is 21.6 MPa (220 kgf/cm²), with shift pressure of 0.5→17.2 MPa (5→175 kgf/cm²).

4. Fluid Viscosity and Temperature Control

The PVD series operates with oil temperature of 15–60 ℃. ISO VG32 or VG46 anti-wear hydraulic oil is recommended. High viscosity during cold start increases suction resistance and cavitation risk; preheating hydraulic oil or using low pour point fluid is recommended in cold environments. Case drain maximum permissible backpressure must not exceed 2 bar absolute to ensure case sealing operates within safe pressure limits.

5. Restart Procedure After Extended Shutdown

If the pump has been idle for more than 30 days, manually rotate the shaft several turns to verify free rotation before restarting. Check for abnormal leakage at the case drain port. After startup, operate at low pressure for 10–15 minutes until oil temperature reaches normal operating range before applying full load. Regularly inspect the spline shaft and drive coupling engagement during operation, ensuring sufficient keyway engagement length (at least 2/3 of the coupling width) to prevent spline wear.