Nachi PVD-08-18P-6G3-4191A Hydraulic Pump 4654364 for Hitachi ZX16-3 ZX17U-2 ZX18-3

1. Basic Product Information

2. Diagnostic Guide: 4 Signs Your Hitachi Mini Excavator Needs a New Pump

Mini excavators rely heavily on a highly responsive hydraulic pump. If your Hitachi ZX16-3, ZX17U-2, or ZX18-3 exhibits any of the following symptoms, the internal cylinder block, pistons, or swashplate of your Nachi pump may be compromised:

1. Sluggish Arm or Bucket Movement: The hydraulic functions slow down significantly as the machine warms up, signaling excessive internal leakage within the piston group.
2. One-sided Tracking Drift: If the excavator constantly veers to one side during straight travel, it often indicates unbalanced oil flow from one of the main pump sections.
3. Severe Vibration and Hydraulic Noise: Abnormal whining or knocking noises from under the canopy usually point to cavitation or shattered piston shoes inside the casing.
4. Sudden Drop in System Pressure: The machine loses digging power and struggles to penetrate hard ground, indicating the pump can no longer hit or sustain its rated pressure.

3. Key Engineering Features

• 100% Direct Bolt-on Fitment: Engineered as an exact replacement for Hitachi OEM P/N 4654364. The mounting flange, splined input shaft, and hydraulic port threads perfectly match your machine's original setup with zero hose adjustments required.
• Integrated Multi-Circuit Design: The Nachi PVD-08-18P series features a compact, integrated design combining dual variable displacement axial piston pumps with a gear pump, ensuring smooth compound operations simultaneously.
• Superior Wear Resistance: Features high-grade bimetallic valve plates and hardened alloy steel pistons that withstand high-speed friction, significantly reducing wear under continuous heavy-duty cycles.
• Pre-calibrated Performance: Every pump is pre-tested on a precision hydraulic test bench to ensure flow rate balance, pressure limits, and regulator settings are pre-calibrated to Hitachi factory standards before shipping.

4. Compatibility & Interchange List

Direct Fit Mini Excavator Models:

• Hitachi Zaxis ZX16-3
• Hitachi Zaxis ZX17U-2
• Hitachi Zaxis ZX18-3

Complete Interchangeable Part & Manufacturer Codes:

• Hitachi OEM: 4654364
• Nachi Model: PVD-08-18P-6G3-4191A / PVD-08-18P

5. Installation & Maintenance Best Practices

To guarantee a successful installation, protect your 12-month warranty, and maximize the lifespan of your new Nachi hydraulic pump:

• Casing Priming is Vital: Never dry-start the pump. Fill the pump casing completely with clean hydraulic oil through the highest drain port before cranking the engine for the first time.
• Flush the Hydraulic Tank: Drain the old hydraulic oil and completely flush the entire system. Any metallic debris from your previous broken pump will instantly score the new rotary group.
• Replace All Hydraulic Filters: Always install a new hydraulic return filter and suction strainer during the pump replacement process.

6. Why Choose BELPARTS?

• 10+ Years of Machinery Expertise: Established in September 2013, Belparts specializes in heavy and mini excavator hydraulic systems.
• Global Distribution Network: Our products are trusted by repair shops and fleet owners in over 150 countries.
• Vast Warehouse Inventory: Backed by our physical shop and warehouse in Guangzhou, we keep premium Nachi, KYB, and Rexroth replacement units in stock.
• 1-Year Warranty & Free Parts: We offer a rock-solid 1-Year Warranty with free replacement parts for any manufacturing defect.
• Tailored Logistics: Air Express (DHL/FedEx/UPS) 3-7 days; Sea Freight 30-45 days for bulk orders.

7. Technical FAQ

Q1: What is the relationship between Nachi PVD-08-18P-6G3-4191A and Hitachi part number 4654364?
A: Nachi is the OEM manufacturer for Hitachi mini excavator hydraulic pumps. 4654364 is Hitachi's parts code; PVD-08-18P-6G3-4191A is the Nachi manufacturer model. They refer to the exact same pump assembly.

Q2: Does this pump come with the pilot pump and regulators?
A: Yes. Our Nachi PVD-08-18P is a complete assembly including the integrated pilot/charge gear pump and control regulators, fully assembled and calibrated for plug-and-play installation.

Q3: What quality options are available?
A: Genuine Nachi Original Brand New (imported from Japan) and Belparts Premium Aftermarket New (built with strict dimensional accuracy at a competitive price).

Q4: How is the pump packaged for international shipping?
A: The pump is treated with anti-corrosion oil, sealed with plastic caps on all ports, wrapped in protective heavy plastic, and packed in a robust export-standard wooden box.