SK120-3 SK120-5 SH120-2 MSG-85P YN15V00001F1 KYB MSG-85P Slewing Swing Motor Assembly Compatible with Kobelco Sumitomo Kato

The KYB MSG-85P Slewing Swing Motor Assembly (OEM Part # YN15V00001F1 / 18251-09000 / MSG-85P / MSG-85P-12E) combines both the high-torque axial piston hydraulic swing motor and the multi-stage planetary reduction gearbox designed for 12-to-14-ton excavators.

• Factory Wholesale Price: $2,200 – $4,200 USD (Direct manufacturer pricing — Save up to 50% vs regional dealer markups)
• MOQ & Bulk Discount: 1 Unit (Tiered wholesale discounts available for batch container orders)
• Lead Time: 1–3 business days (Large factory stock ready for immediate worldwide dispatch)
• Warranty: 12 Months full replacement warranty with 100% bench test video proof

Engineered to deliver high rotation torque and anti-rebound brake control under demanding field applications:

• Urban Pipe Trenching & Utility Laying: Fine rotation positioning control during ditch excavation and municipal pipe placement with Kobelco SK120-5 excavators.
• Heavy Foundation Digging & Earthmoving: Rapid 360-degree swing loading cycles when dumping gravel and clay into heavy haul trucks with Sumitomo SH120 excavators.
• Building Demolition & Concrete Crushing: Heavy-duty casing built to withstand severe side-impact loads and breaker tool vibration feedback.
• Forestry & Agriculture Land Clearing: Reinforced shaft seal group prevents dust, mud, and water ingress in muddy outdoor operating environments.

If your 12–14 ton excavator is experiencing swing mechanism failure, consult the diagnostic guide below:

• Fault 1: Weak Swing Power or Slow Rotation (回转无力/动作发慢)
  Root Cause: Excessive wear on the motor cylinder block valve plate or internal friction brake plate degradation.
  Solution: Replace worn rotary group parts or install a complete drop-in MSG-85P slewing motor assembly (OEM YN15V00001F1).
• Fault 2: Severe Shaking, Jerking or Abnormal Metallic Noise During Rotation (抖动异响/回转卡顿)
  Root Cause: Broken teeth in planetary gears, worn drive shaft bearings, or pitted swing ring pinion teeth.
  Solution: Inspect reduction gear teeth and replace drive shaft bearings immediately to prevent complete gearbox lockup.
• Fault 3: Hydraulic Oil Leakage From Main Drive Shaft Seal (回转轴封漏油)
  Root Cause: Clogged casing drain line causing excessive internal housing pressure, blowing out the drive shaft seal.
  Solution: Clear drain circuit line and install a high-pressure skeleton oil seal group.
• Fault 4: Swing Drift / Auto-Slewing Slip When Parked on an Incline (斜坡停车自动溜车)
  Root Cause: Mechanical parking brake disc wear or sticky brake solenoid valve spool failing to seat properly.
  Solution: Replace brake disc plates and clean/recalibrate the swing parking brake solenoid valve.
• Fault 5: High Operating Oil Temperature & Torque Loss After 1 Hour (高温掉压)
  Root Cause: Thermal expansion oil bypass caused by score marks on the distributor valve face.
  Solution: Lap valve plate face or replace complete hydraulic motor section.

Explore our factory-direct replacement components compatible with major global excavator brands:

Q1: How do I verify if this slewing motor fits my Kobelco SK120-5 excavator?
A: Check your original swing motor tag for OEM part numbers YN15V00001F1, 18251-09000, or MSG-85P stamp. You can also send us your machine serial number for instant fitment check.

Q2: My Sumitomo SH120 excavator drifts when parked on a slope. Will replacing this MSG-85P swing motor solve it?
A: Yes, swing drift on slopes is caused by worn brake discs inside the motor gearbox or a failing brake solenoid valve. Installing our complete MSG-85P motor assembly restores firm parking brake holding power.

Q3: Is this MSG-85P slewing motor bench tested before shipment?
A: Yes, every single MSG-85P swing motor undergoes a rigorous factory bench pressure test up to 280 Bar and volumetric efficiency check. A live test video is provided before dispatch.