PC200-7 PC220-7 708-2L-00300 MB85-7 MB85 Slewing Swing Motor Repair Kit Compatible with Komatsu

1. Product Overview & Wholesale Price Range

The Komatsu PC200-7 / PC220-7 MB85 Slewing Swing Motor Repair Kit (OEM Part # 708-2L-00300 / 708-2L-00112 / MB85 / MB85-7) includes the complete internal rotary group overhaul set: cylinder block, piston shoes with bronze slippers, distributor valve plate, retainer plate, ball guide, swash plate cradle, drive shaft, and brake discs designed for 20-to-22-ton excavators undergoing swing motor overhauls.

• Factory Wholesale Price: $320 – $680 USD (Direct manufacturer pricing — Save up to 50% vs regional dealer markups)
• Included Core Spare Parts: Cylinder Block (1pc) + Piston Shoes (9pcs) + Valve Plate (1pc) + Retainer Plate (1pc) + Ball Guide (1pc) + Swash Plate (1pc) + Brake Discs Set
• MOQ & Bulk Discount: 1 Set (Tiered wholesale discounts available for hydraulic repair shop batch orders)
• Lead Time: 1–3 business days (Large factory stock ready for immediate worldwide dispatch)
• Warranty: 12 Months full replacement warranty with high-lead bimetallic bronze durability guarantee

2. Application Worksite Checklist (施工场景清单)

Engineered to restore original rotation torque and smooth swing control across demanding 20-22 ton excavator jobsites:

• Heavy Open-Pit Mining & Quarrying: Restores maximum swing torque during continuous heavy rock loading with Komatsu PC200-7 and PC220-7 excavators.
• Deep Foundation Excavation & Earthmoving: High thermal resistance bimetallic plates prevent swing power loss during continuous long-hour digging.
• Highway Infrastructure & Utility Trenching: Micro-lapped valve faces ensure precise 360-degree positioning control during pipe laying.
• Demolition & Heavy Breaker Operations: Forged alloy steel pistons absorb continuous side-impact shocks from rock breakers.

3. Slewing Swing Motor Overhaul & Fault Diagnostic Guide (维修包常见故障排查)

If your Komatsu PC200-7 excavator swing mechanism is exhibiting performance degradation, check the wear symptoms below:

• Fault 1: Thermal Swing Pressure Loss & Rotation Slowdown After 1 Hour (热车回转掉压发慢/内泄)
  Root Cause: Wear gap between the cylinder block face and distributor valve plate surface causing internal high-pressure thermal oil bypass.
  Solution: Replace the worn rotary group with our precision lapped MB85 cylinder block and valve plate kit (OEM 708-2L-00300).
• Fault 2: 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 score marks on the swashplate cradle pivot.
  Solution: Install our MB85 overhaul kit with new friction brake discs and swashplate group to restore firm holding torque.
• Fault 3: Severe Shaking, Jerking or Metallic Noise During Swing (回转抖动卡顿异响)
  Root Cause: Loose piston slipper heads, broken retainer plate spring, or worn ball guide.
  Solution: Replace retainer plate, ball guide, and piston shoe set to eliminate mechanical play and chatter.
• Fault 4: Black Copper Filings Found in Hydraulic Return Oil Filter (油箱内有黑粉铜屑)
  Root Cause: Friction galling and thermal melting of the bronze layer on the piston slippers under high pressure.
  Solution: Flush the entire hydraulic oil circuit, clean control valves, and rebuild motor with high-lead bronze MB85 pistons.

4. Hot Machinery Replacement Parts Recommendation (5大品类热门推荐表)

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

5. Frequently Asked Questions & Technical Support (QA 问答专区)

Q1: How do I verify if this MB85 repair kit fits my Komatsu PC200-7 or PC220-7 swing motor?
A: Check your original swing motor tag for OEM part numbers 708-2L-00300, 708-2L-00112, or MB85 stamp. You can also send us clear photos of your old cylinder block and piston slippers for instant fitment verification.

Q2: What is the material hardness of the MB85 cylinder block and piston slippers?
A: Our MB85 cylinder blocks are made of high-density forged alloy steel with bimetallic copper-alloy distribution faces, and the piston shoes feature high-lead bronze slippers rated for continuous 350 Bar working pressure.

Q3: Is this MB85 repair kit a complete overhaul solution for swing motor rebuilds?
A: Yes, it includes all major internal wear components (cylinder block, 9 pistons, valve plate, retainer plate, ball guide, swashplate, and friction brake discs) required for a complete motor rebuild.