Description
Rapid and precise upperstructure slewing on the Caterpillar 320C heavy excavator is delivered by a high-pressure axial piston swing motor bolted directly to the planetary reduction gearbox. Tatan Machinery supplies 100% Brand New M2X150 hydraulic swing motor assemblies (OEM part numbers: 179-9778 / 191-5611, interchangeable with 161-8919 / 168-7873). Pre-fitted with a multi-disc mechanical parking brake pack, dual port relief shock valves, and anti-rebound cushion spools, every motor is dynamically tested on our test stand under 26.5 MPa working pressure and backed by our 12-Month Comprehensive Replacement Warranty.
Source Verification: First-Party Physical Stockholding
We are a specialized stocking supplier of excavator hydraulic components. We do not dropship unverified goods. All hydraulic pumps, control valves, and final drives supplied on our site are 100% Brand New (our diesel engine assemblies are remanufactured to OEM tolerances).
| Supplying Entity: | Tatan Machinery (Excavator Component Exporter) |
| Component Classification: | Excavator Swing Motor Assembly / Hydraulic Parts |
| Hydraulic Motor Core: | M2X150 Series Swashplate Axial Piston Slew Motor |
| OEM Master Assembly Code: | 179-9778 / 191-5611 (Cross Ref: 161-8919, 168-7873, 215-9964) |
| Manufacturing Standard: | 100% Factory Brand New (Unused, Full Bench Pressure Certified) |
| Target Machine Brand: | Caterpillar Excavator Parts Collection |
📦 Heavy Swing Motor Inventory & Staging Verification
Physical stock ready for crating, brake release port inspection, and serial tag verification:
Physical inventory verified — no broker middleman. Live photos of serial number tags provided upon inquiry.
Hydraulic & Mechanical Fitment Specifications
| Engineering Property | Design Metric |
|---|---|
| Motor Displacement | 150 cc/rev (Fixed Displacement Piston Core) |
| Rated Operating Pressure | 26.5 MPa (265 bar / 3,843 PSI) / Peak Overload Relief: 28.0 MPa |
| Rated Output Torque | Approx. 630 N·m (at 26.5 MPa) High-Torque Slewing Effort |
| Mechanical Parking Brake | Spring-Applied, Hydraulically Released Wet Multi-Disc Brake (Hold Torque: 820 N·m) |
| Brake Release Pilot Pressure | 0.6 ± 0.1 MPa (Brake delay time: 5–8 seconds via integrated check valve) |
| Anti-Reaction Cushion Valve | Dual Anti-Shock Damping Relief Valves to Prevent Slew Rebound |
| Dry Assembly Weight | Approx. 75 kg (165 lbs) Complete Motor Head with Relief Block |
| Standard Machine Match | Caterpillar 320C / 320C L / 320C LN (20-Ton Excavators) |
Field Reality: Why Rebuilding Worn CAT 320C Swing Motors Fails
A 20-ton excavator swinging a loaded bucket 1,000 times a day creates enormous rotational momentum. When internal hydraulic wear strikes, field repairs with generic seal kits fail to solve structural issues:
- Dangerous Slew Drift on Inclines: When loading dump trucks on a hillside with the swing joystick centered, the upper carriage slowly rotates downhill. The internal multi-disc wet friction plates are glazed, or valve plate micro-sealing lands are grooved, allowing holding oil to slip to tank.
- Violent Slew Stop Shudder & Rebound: When releasing the swing lever to stop over a haul truck, the cab shudders violently, bounces backward 15 cm, and clanks against the ring gear. The internal anti-reaction shock relief valves are scored or plugged with carbonized sludge.
- Hydraulic Oil Leaking Past Shaft Seal into Slew Gearbox: High drain backpressure blows out the motor lower output shaft seal. High-pressure hydraulic oil floods the planetary reduction gearbox, overfilling the grease cavity and blowing oil out through the dipstick.
- Slow Swing Acceleration Under Full Bucket: The excavator turns sluggishly when swinging uphill against gravity. Excessive case-drain leakage indicates the cylinder barrel and brass slipper shoes have galled, destroying volumetric efficiency.
Factory Dyno Testing & 12-Month Component Warranty
To guarantee smooth, shock-free slewing on your jobsite, every 179-9778 swing motor is bench-tested on our automated digital dynamometer before export approval:
- Slew Overload Relief Pressure Calibration: Port overload relief cartridges set to exact Cat 320C factory specs (26.5 MPa continuous / 28.0 MPa shock peak) on our high-torque motor test stand.
- Mechanical Parking Brake Static Hold Test: Static torque test verifying the multi-disc wet brake securely locks rotation up to 820 N·m, and releases completely at 0.6 MPa pilot pressure.
- Anti-Reaction Cushion Valve Damping Verification: Testing the cushion check valve flow curve to ensure smooth stopping without uncommanded swing bounce.
- Internal Case Drain Leakage Verification: Continuous testing under full operating temperature (55°C) to ensure internal slippage is below OEM limits, preventing heat buildup.
📹 Workshop Swing Motor Dyno Testing Live Clip
Watch our technician inspect swing relief pressure, brake release, and output splines:
✓ Live unit filmed on hydraulic test stand at Tatan Machinery facility
Export Packing & Logistics Dispatch
Precision motor rotating groups require absolute protection against moisture and ocean transit shock:
- Threaded Metal Port Plugs: Main working ports, brake release pilot port, and case drain port fitted with heavy-duty metal blanking caps.
- VCI Vapor-Phase Anti-Rust Foil: Bare output shaft splines and unpainted mounting pilots coated with thick anti-rust grease and vacuum-sealed in VCI protective foil.
- Rigid Timber Base Skid Bolting: The motor is anchored upright through its mounting pilot flange into custom-cut solid wood framing inside an ISPM 15 export crate.
- Prompt Global Shipping: Air express via DHL/FedEx (3–7 days) for machine-down emergencies, or consolidated sea freight (LCL/FCL) with complete HS Code (8412.29) paperwork.
Sealed steel port caps, protective anti-corrosion wax, and reinforced wooden crating
Field Commissioning Rules: Protect Your New Swing Motor
To protect your 12-month warranty, technicians MUST adhere to these critical procedures during installation:
- MANDATORY: Pre-Fill Motor Casing with Clean Hydraulic Oil: Before connecting working hoses, remove the top case-drain plug and fill the motor casing completely with clean ISO VG 46 hydraulic oil. Running a new swing motor dry for even 3 seconds will instantly seize the rotating cylinder barrel and brass slipper shoes!
- Check Swing Reduction Gearbox Oil: Before bolting the motor onto the reduction gearbox, check the gear oil (Cat FDAO / SAE 80W-90) inside the gearbox. If the old motor leaked oil into the gearbox, drain and refill the gearbox to the proper dipstick level.
- Verify Parking Brake Release Pilot Pressure: Hook up a pressure gauge to the brake release pilot port. Confirm that the pilot signal reaches at least 3.9 MPa when moving the swing joystick, ensuring the wet brake discs release fully without dragging.
- Case Drain Hose Inspection: Ensure the case drain hose returning to the hydraulic reservoir is 100% free of kinks or blockage. High drain backpressure will blow out the motor output shaft seal!
- Bleed Air on Low-Idle Rotation: Operate the swing left and right at low engine idle for 5 minutes without hitting end-stops to purge all air from the relief manifold.
Procurement Decision FAQ: What Buyers Ask
Q: Is this M2X150 swing motor brand new or remanufactured? Does it include the brake pack?
A: This M2X150 swing motor is 100% Brand New with zero operating hours. It comes completely assembled with a brand-new mechanical wet multi-disc parking brake pack, dual port relief valves, anti-rebound shock valves, and the brake delay switching valve. It is a complete drop-in replacement ready to bolt directly onto your CAT 320C reduction gearbox.
Q: Are your hydraulic components brand new? Why are your engines remanufactured?
A: Every hydraulic pump, main control valve, travel motor, and swing motor on our site is 100% Brand New. Only our heavy diesel engine assemblies on this site are professionally remanufactured with brand-new internal wear components. You can order with absolute confidence in factory-new metallurgical reliability.
Q: My CAT 320C has part number 191-5611 or 161-8919. Is this completely interchangeable?
A: Yes. 179-9778, 191-5611, and 161-8919 are directly interchangeable Caterpillar OEM part numbers used across 320C and 320C L production batches (prefixes AMC, ANH, BCK, BPR, RAW). Send your machine’s 17-digit PIN number from the cab tag and clear photos of your current motor nameplate to Gavin. We cross-verify the exact motor arrangement code in the official Caterpillar parts database within 10 minutes.
Q: Can I see live test bench video and stamped serial numbers of the actual motor before dispatch?
A: Absolutely yes. Prior to balance payment and dispatch, we send clear photos and live video of the exact unit assigned to your order. You will see the stamped serial tag, output spline teeth, sealed steel port plates, and the wooden box packaging process.
Q: What happens if the motor crate is damaged during sea freight, and what customs documentation is supplied?
A: Every shipment from Tatan Machinery is protected by full commercial marine cargo insurance. The motor is bolted down directly onto internal skids within a fumigation-free solid plywood crate. We supply commercial invoices with accurate HS Codes (8412.29), detailed packing lists, and Certificates of Origin for smooth customs clearance at your destination port.
🔗 Frequently Purchased Together with CAT 320C Swing Motor:
- DIESEL ENGINE:
Caterpillar 320C 3066T Diesel Engine Assembly (172-5184)
Remanufactured - MAIN VALVE:
Main Control Valve Assembly (172-5636) for Caterpillar 320C
100% Brand New - HYDRAULIC PUMP:
SBS80 / AP-12 Main Hydraulic Pump (172-5638) for Caterpillar 320C
100% Brand New - FINAL DRIVE:
Final Drive Travel Motor Assembly for Caterpillar 320C
100% Brand New - BRAND CATALOG:
View All Caterpillar Excavator & Heavy Equipment Parts Collection
Get Wholesale Factory Quote for CAT 320C Swing Motor 179-9778
Looking for direct factory pricing, stock availability, or 12-month warranty terms for Cat 320C swing motors? Contact senior specialist Gavin now!
💡 Fast Quote: Send your machine serial number or current motor nameplate photos for an accurate match within 10 minutes!
* Note: Wholesale Reference Price Starts From $300.00. Please contact Gavin for a final customized quote based on freight destination and configuration.
* Note: Wholesale Reference Price Starts From $300.00. Please contact Gavin for a final customized quote.
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