ZX450-6 ZX470-3 Swing Motor Assembly 4642948 Hydraulic Slewing Device Compatible with Hitachi
We supply the heavy-duty ZX450-6 ZX470-3 excavator swing motor assembly (Part No. 4642948 / 4437285), precision-manufactured as a high-performance aftermarket hydraulic replacement compatible with Hitachi 450-6 and 470-3 series heavy machinery. Engineered for heavy-duty earthmoving and mining applications, this hydraulic slewing device provides maximum rotational torque, rapid acceleration, and zero hydraulic bypass leakage.
Price Range Indicator:
- Complete Drop-In Slewing Device (Motor + Reduction Gearbox): $3,800 – $5,200 USD (Ready for instant jobsite replacement)
- Hydraulic Motor Section Only (Rotary Group & Valve Block): $2,200 – $3,200 USD (Cost-effective repair option)
| Comparison Dimension | Complete Slewing Device (Full Assembly) | Hydraulic Motor Section Only |
|---|---|---|
| Price Range | $3,800 – $5,200 USD | $2,200 – $3,200 USD |
| Included Components | Hydraulic Motor + Brake Valve + Planetary Reduction Gearbox + Output Shaft | Cylinder Block + Piston Shoes + Valve Plate + Swash Plate + Shaft Seal |
| Jobsite Downtime | Ultra-Short (2–4 Hours direct plug-and-play) | Medium (8–12 Hours requiring gearbox teardown) |
| Solved Failure Symptoms | Gear crunching, housing cracks, total lockup, internal seal failure | Weak rotation torque, hydraulic drift, oil leakage at shaft |
To ensure 100% operational reliability under continuous 35 MPa pressure, every ZX450-6 / ZX470-3 swing motor undergoes strict bench testing before dispatch:
- Raw Material & Housing Casting Inspection: Ultrasonic defect testing to prevent internal casting cracks under shock loads.
- Precision CNC Machining Audit: Micron-level tolerance checks on the cylinder block and valve plate surface.
- 35 MPa Hydraulic Pressure Hold Test: High-pressure bench test verifying relief valve setting and internal leakage limits.
- Brake Disengagement & Torque Test: Validating mechanical parking brake release timing and holding capability.
- Final Cleanliness & Oil Seal Audit: ISO 4406 fluid cleanliness verification and zero-leakage shaft seal testing.
If your 45-ton to 47-ton excavator is showing performance degradation, refer to these SIS-backed troubleshooting solutions:
- 1. Automatic Swing Drift on Slopes (斜坡停车自动溜车/滑移): Caused by worn mechanical brake friction discs or a jammed brake release solenoid valve. Replacing the complete slewing assembly restores full holding power.
- 2. Slow or Weak Rotation (回转无力/动作发慢掉压): Caused by severe scoring on the cylinder block and valve plate or main relief valve bypass leakage under high temperature.
- 3. Severe Shaking & Abnormal Crunching Noise (回转异响与剧烈抖动): Caused by pitted planetary gear teeth, broken output shaft bearings, or excessive backlash inside the gear drive.
- 4. Hydraulic Fluid Leaking Into Gearbox (回转马达漏油/串油):): Caused by aged high-pressure shaft seals or excessive casing backpressure damaging the seal lip.
- 5. Overheating Hydraulic Motor (回转马达系统高温): Caused by excessive internal oil bypass friction or clogged pilot pressure lines.
Q: Why does my Hitachi ZX450-6 excavator drift automatically when holding a heavy load on a slope?
A: Slope drift is typically triggered by worn mechanical brake plates inside the reduction gearbox or a faulty swing parking brake valve that fails to engage hydraulic holding pressure. Inspect the brake valve circuit or replace the complete swing device assembly (Part No. 4642948).
Q: Can I install this swing motor on both ZX450-6 and ZX470-3 models?
A: Yes. The ZX450-6 and ZX470-3 share identical hydraulic mounting dimensions, shaft splines, and main relief valve pressure ratings, making Part No. 4642948 a direct interchangeable drop-in replacement.
| Category | Equipment Model | OEM Part Number | Application & Compatibility |
|---|---|---|---|
| Hydraulic Main Pump | ZX450-6 / EX200-6 | 4503280 / K3V140DT | Compatible with Hitachi 20t-45t Excavators |
| Swing Motor Assembly | ZX450-6 / ZX470-3 | 4642948 / 4437285 | Compatible with Hitachi Heavy Excavator Slewing Device |
| Travel Motor Final Drive | CAT 320C / ZX450 | 191-8390 / 9233692 | Compatible with CAT & Hitachi Final Drives |
| Main Control Valve | ZX350-6 / ZX450-6 | 4653603 / 4652233 | Compatible with Multi-Way Hydraulic Distributing Valves |
| Diesel Engine Assembly | CAT 3306 / 6WG1 | 2W-2800 / 4N-0200 | Complete Diesel Engine Assembly for Heavy Excavators |
