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Hitachi EX300-2/EX300-3 Excavator Swing Motor Assembly
Welcome to our heavy machinery hydraulic supply center. We specialize in providing the complete EX300-2 / EX300-3 excavator swing motor assembly (Part No. 4294479 / M2X210), precision-manufactured as a heavy-duty aftermarket replacement part compatible with Hitachi large engineering machinery equipment. Built to deliver original slewing torque and heavy-load rotation stability, this swing device ensures maximum productivity on demanding job sites.
Key Technical Specifications & Parameters
- Product Name: Swing Motor Assembly / Slewing Motor Device / Swing Reduction Gearbox
- Applicable Machine Models: Fit for Hitachi EX300-2, EX300LC-2, EX300-3, EX300LC-3 Excavators
- Reference Part Number / Motor Code: 4294479 / M2X210 / 4398514
- Key Internal Components: Swashplate piston motor, integrated swing valve, heavy-duty planetary gear reduction set
- Condition: 100% Brand New Aftermarket / Direct OEM Fit Replacement
- Warranty & Quality Assurance: 100% Factory Hydraulic Pressure Tested, 6–12 months warranty included
EX300-2 / EX300-3 Swing Motor Common Faults & Solutions
Over time, heavy slewing loads cause internal wear. Replacing your worn device with our complete EX300-2 / EX300-3 swing motor assembly directly solves these critical performance issues:
1. Weak Swing Torque / Slow Rotation (回转无力)
Cause: Severe internal scoring on cylinder block, worn pistons, or reduced hydraulic holding pressure.
Fix: Installing our assembly restores full hydraulic pressure and fast, powerful 360-degree slewing capability.
2. Abnormal Noise & Heavy Vibration (抖动异响)
Cause: Pitted planetary gears, chipped pinion shaft, or worn slewing bearings.
Fix: Complete unit replacement eliminates gear mesh backlash and protects your excavator’s main slewing ring.
3. Hydraulic Oil Leakage from Motor Shaft (回转漏油)
Cause: Blown main oil seals or cracked housing from system pressure spikes.
Fix: Pre-installed high-pressure Japanese oil seals effectively seal fluid and prevent gear oil contamination.
4. Swing Sticking / Jerky Rotation (回转卡顿)
Cause: Contaminated hydraulic fluid blocking brake valve spools or sticking pistons.
Fix: Precision clearance machining ensures smooth start/stop slewing response without sudden braking jerk.
5. Overheating Swing Reduction Unit (高温)
Cause: Friction buildup caused by insufficient lubrication or misaligned internal gears.
Fix: Optimized lubrication channels and hardened alloy gears keep operational temperatures within safe limits.
Worksite Applications & Operating Scenarios
Built for tough 30-ton class excavator applications, this swing motor assembly suitable for Hitachi EX300-2 / EX300-3 performs reliably in:
- Heavy Mining & Quarry Operations: High torque output supports rapid cycles with oversized bucket capacities.
- Infrastructure & Earthmoving Construction: Smooth brake control allows accurate digging and trench alignment.
- Demolition & Rock Breaking: Rigid housing resists heavy dynamic shocks during hammer operations.
Frequently Asked Questions (FAQ)
Q: Where can I buy a replacement swing motor assembly compatible with Hitachi EX300-2 or EX300-3?
A: You can purchase brand-new aftermarket EX300-2 and EX300-3 swing motor assemblies directly from our warehouse. We supply complete units ready for bolt-on installation on Hitachi machines.
Q: What is the OEM part number for the Hitachi EX300-2 swing motor?
A: Common OEM reference numbers for the EX300-2 / EX300-3 swing device include 4294479, 4398514, and motor model M2X210. Please verify your old motor tag or contact us for confirmation.
Q: Is this EX300-3 swing motor a direct drop-in replacement?
A: Yes, it features exact original mounting bolt patterns, hose port threads, and output shaft splines, requiring no pipeline or structural modifications.
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