Description
Tatan Machinery supplies 100% Brand New hydraulic swing motor assemblies (OEM part numbers: 708-7S-00030 / 708-7S-00031, interchangeable with 20S-26-31100 / 708-7S-00032) engineered for Komatsu PC20-7, PC20R-7, and PC25-1 mini crawler excavators. Mounted onto the upper revolving deck, this axial piston motor drives the planetary slew reduction gearbox to rotate the cab and boom assembly under heavy trenching loads. Built with an internal wet-disc parking brake pack and dual cushion shock-relief valves, each motor is 100% bench-tested for brake release pressure, starting torque, and case drain sealing. Backed by our 12-Month Comprehensive Replacement Warranty.
Verified Supplier Identity & Facility Proof
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).
| Supplier Entity: | Tatan Machinery (Physical Excavator Parts Wholesaler & Exporter) |
| Product Category: | Excavator Swing Motor Assembly / Hydraulic Parts |
| Component Type: | Compact Axial Piston Swing Motor with Built-in Relief Manifold |
| OEM Assembly Part No: | 708-7S-00030 / 20S-26-31100 (Cross Ref: 708-7S-00031, 708-7S-00032) |
| Product Condition: | 100% Brand New (Zero Hours, Pre-Tested Complete Assembly with Relief Cartridges) |
| Warranty Coverage: | 12 Months / 1-Year Comprehensive Replacement Warranty |
| Target Machine Brand: | Komatsu Excavator Parts Collection |
🏢 Physical Facility & Stock Walkthrough
Take a live look at our component inventory, pallet racks, and dispatch facility:
✓ Real physical store & inventory filmed at Tatan Machinery facility
Technical Specifications
| Parameter | Specification Data |
|---|---|
| Motor Design | Fixed-Displacement Swashplate Axial Piston Motor (Compact Slew Type) |
| Working Circuit Relief Pressure | 19.6 MPa (200 bar / 2,842 PSI) Factory Preset Overload Port Relief |
| Rated Slew Speed | Approx. 9.5–10.0 RPM Upperstructure Revolutions |
| Parking Brake System | Spring-Applied, Hydraulically Released Wet Multi-Disc Friction Brake |
| Shock Damping Cushion System | Precision Anti-Reaction Check Valves with Calibrated Slew Damping Orifices |
| Total Assembly Weight | Approx. 24.5 kg (54 lbs) Lightweight Compact Design |
| Standard Machine Match | Komatsu PC20-7, PC20R-7, PC25-1 (2.6-Ton Class Mini Excavator) |
When to Replace the Swing Motor on Komatsu PC20-7: Field Diagnostics
Operating 2.6-ton excavators in foundation work and utility trenching creates intense slew inertia shock. When internal motor wear occurs, replace the complete assembly under these severe symptoms:
- Slew Over-Travel & Jerky Stop (Anti-Shock Valve Failure): When releasing the swing lever to dump dirt into a trench, the cab bounces backward violently or drifts 10–15 cm before stopping. The internal anti-reaction shock relief valves are scored or jammed with carbonized oil.
- Upperstructure Slope Creep & Slew Drift on Inclines: Parking on a foundation slope with the swing joystick centered, the bucket and cab slowly rotate downhill. The wet parking brake friction plates are burned and glazed, or the valve plate has micro-bypass leakage directly to tank.
- Sluggish Swing Acceleration Under Load: Slewing becomes extremely weak and hesitates when swinging a loaded mud bucket uphill. Excessive case-drain leakage indicates the cylinder barrel and brass slipper shoes have scored.
- Hydraulic Oil Leaking Past Shaft Seal into Slew Reduction Gearbox: High drain backpressure blowing out the motor output shaft seal, flooding the planetary reduction gearbox with hydraulic oil and blowing oil out through the gearbox dipstick.
Workshop Bench Testing & 12-Month Warranty Guarantee
Every 100% Brand New 708-7S-00030 swing motor supplied by Tatan Machinery comes backed by a 12-Month Comprehensive Replacement Warranty. Before export packaging, our technicians complete a 5-point quality validation:
- Slew Overload Relief Pressure Calibration: Port overload relief cartridges calibrated to exact Komatsu PC20-7 factory specifications (19.6 MPa / 200 bar) on a digital motor test bench.
- Mechanical Parking Brake Static Hold Test: Verifying the multi-disc wet friction brake firmly locks rotation at zero pilot pressure and releases cleanly when pilot signal is applied.
- Anti-Reaction Damping Orifice Verification: Testing the cushion check valve flow curve to ensure smooth stopping without uncommanded swing bounce.
- Case-Drain Internal Leakage Measurement: Precision flow-meter measurement at working oil temperature (55°C) to verify volumetric efficiency (>92%).
- Drive Spline Shaft Hardness & Concentricity Check: Coordinate measurement of output shaft splines to ensure backlash-free engagement with the PC20-7 planetary slew gearbox.
📹 Live Swing Motor Workshop Inspection Video
Watch our engineer verify swing motor relief valves, brake pilot port, and output splines:
✓ Real physical unit filmed at Tatan Machinery workshop
Export Heavy-Duty Packaging Process
Precision motor rotating groups require absolute protection against moisture and freight shock:
- 100% Sealed Metal Port Caps: Main working ports, brake release pilot port, and case drain port fitted with heavy-duty metal blanking caps.
- Anti-Corrosion Wax Coating: Output drive splines and unpainted mounting pilots coated with heavy anti-rust grease and vacuum-sealed in VCI protective foil.
- Custom Molded Internal Framing: The motor is securely braced upright inside structural high-density wood cushioning.
- ISPM 15 Fumigation-Free Solid Plywood Box: Sealed export crate banded with galvanized steel straps.
Actual sealed port caps and heavy-duty crating for 708-7S-00030 swing motor
Global Shipping & Customs Documentation
Fast, reliable dispatch tailored for commercial contractors and parts wholesalers worldwide:
- Emergency Machine Down Air Cargo: Fast air express via DHL Aviation, FedEx Freight, or international airlines within 3–7 business days.
- Consolidated Ocean Sea Freight (LCL / FCL): Direct containerized shipping to worldwide commercial ports.
- Clean Customs Clearance Paperwork: Commercial Invoices with correct HS Code (8412.29 – Hydraulic Motors), Packing Lists, and Certificates of Origin for tariff optimization.
Container loading and air freight dispatch supported by global logistics partners
Critical Installation Guidelines (PC20-7 Slew Mechanic Checklist)
To prevent instant dry-run failure and protect your 12-month warranty, technicians MUST adhere to these critical procedures:
- 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!
- Clean Slew Gearbox Grease Cavity: Before mounting the motor, inspect the grease level inside the planetary slew reduction gearbox. Remove old contaminated sludge and refill with fresh extreme-pressure molybdenum disulfide grease.
- Verify Parking Brake Release Pilot Pressure: Hook up a pressure gauge to the brake release port. Confirm that the pilot signal reaches at least 2.5–3.5 MPa when the swing joystick is moved, ensuring the brake friction discs release completely 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.
Buyer Frequently Asked Questions (Purchasing FAQ)
Q: Is this 708-7S-00030 swing motor brand new or remanufactured? Does it include the brake pack?
A: This swing motor is 100% Brand New with zero operating hours. It comes completely assembled with a brand-new internal wet friction brake pack, dual port relief valves, and anti-rebound shock valves. It is a complete drop-in replacement ready to bolt directly onto your PC20-7 reduction gearbox.
Q: What is covered under your 12-month warranty for this swing motor?
A: Our 12-Month Comprehensive Warranty covers all internal mechanical and hydraulic failures resulting from manufacturing or metallurgical defect—including cylinder barrel seizure, piston shoe detachment, valve plate scoring, brake spring fatigue, and shaft spline failure. If any defect arises under proper hydraulic operating conditions, Tatan Machinery provides prompt replacement support.
Q: My PC20-7 has part number 20S-26-31100 or 708-7S-00031. How do you confirm fitment?
A: These are interchangeable Komatsu OEM part numbers used across PC20-7, PC20R-7, and PC25-1 production batches. Send your machine’s serial number (PIN) from the cab tag and photos of your current motor nameplate to Gavin. We cross-verify the exact motor arrangement code in the official Komatsu 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 Komatsu PC20-7 Swing Motor:
- DIESEL ENGINE:
Komatsu PC20-7 3D84N-2H Diesel Engine Assembly (YM129158-77010)
Remanufactured - MAIN VALVE:
Main Control Valve Assembly (709-35-11100) for Komatsu PC20-7
100% Brand New - HYDRAULIC PUMP:
Main Hydraulic Pump Assembly (705-41-01050) for Komatsu PC20-7
100% Brand New - FINAL DRIVE:
Final Drive Travel Motor Assembly for Komatsu PC20-7
100% Brand New - BRAND CATALOG:
View All Komatsu Excavator & Heavy Equipment Parts Collection
Get Wholesale Factory Quote for PC20-7 Swing Motor 708-7S-00030
Looking for direct factory pricing, stock availability, or 12-month warranty terms for Komatsu PC20-7 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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