PC75-3 PC75UU-3 PC78US-6 708-1W-00030 708-3S-00010 HPV55 Hydraulic Main Pump Assembly Compatible with Komatsu

1. Product Overview & Wholesale Price Range

The Komatsu PC75-3 / PC75UU-3 HPV55 Hydraulic Main Pump Assembly (OEM Part # 708-1W-00030 / 708-3S-00010 / 708-1W-00010 / HPV55) is a variable displacement axial piston tandem pump engineered for 7-to-8-ton mid-size excavators operating under continuous trenching, utility digging, and urban earthmoving works.

• Factory Wholesale Price: $1,850 – $3,600 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

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

Precision-matched displacement control designed for continuous high hydraulic power output under harsh conditions:

• Urban Utility Trenching & Cable Laying: Fine hydraulic flow metering for precise pipe laying and narrow ditch digging with Komatsu PC75UU-3 zero-swing excavators.
• Residential Foundation & Earthmoving: Sustained working pressure under 280 Bar for rapid bucket loading cycles on Komatsu PC75-3 excavators.
• Road Infrastructure & Landscaping Works: Optimized oil displacement for fast bucket loading and grading cycles on PC78US-6 excavators.
• Demolition & Small Breaker Operations: Heavy-duty pump housing protects against continuous pressure shockwaves from hydraulic hammer attachments.

3. Hydraulic Main Pump Troubleshooting & Diagnostic Guide (液压泵常见故障排查)

If your Komatsu 7–8 ton excavator is exhibiting hydraulic system failure, consult the diagnostic guide below:

• Fault 1: Cold Machine Operates Normally, But Machine Slows Down & Drops Pressure After 1 Hour (冷车正常,热车掉压发慢)
  Root Cause: Thermal expansion wear gap between the piston shoes, cylinder block, and valve plate, causing internal high-pressure oil thermal bypass.
  Solution: Replace with a complete drop-in PC75-3 main pump assembly (OEM 708-1W-00030) or overhaul the internal rotary group kit.
• Fault 2: Engine Stalls or Overloads When Actuating Hydraulic Boom/Arm (憋车/发动机过载熄火)
  Root Cause: HPV55 pump regulator power-control spool jammed or hydraulic pilot regulator valve miscalibrated.
  Solution: Recalibrate pump regulator pilot pressure or replace the complete regulator assembly to restore engine horsepower matching.
• Fault 3: Hydraulic Oil Leakage From Drive Shaft Seal Area (主驱动轴封高压串油漏油)
  Root Cause: Clogged casing drain line causing excessive internal housing backpressure, blowing out the front drive shaft skeleton seal.
  Solution: Flush housing drain lines, replace front drive shaft seal, and check gear pilot pump relief pressure.
• Fault 4: Abnormal Cavitation Noise or Severe Vibration From Main Pump (泵体异响抖动/气蚀)
  Root Cause: Air suction at inlet suction pipe, contaminated hydraulic tank filter, or worn drive shaft bearings.
  Solution: Replace suction line seals, flush hydraulic fluid tank, and replace drive shaft roller bearings.
• Fault 5: Black Metallic Filings Found Inside Hydraulic Tank Filter (油箱内有黑粉或金属屑)
  Root Cause: Severe friction galling on swashplate shoe bronze layer or cylinder block face failure.
  Solution: Flush entire hydraulic piping system, clean main control valve, and install a new PC75-3 main pump assembly.

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 main pump fits my Komatsu PC75-3 or PC75UU-3 excavator?
A: Check your original pump nameplate for OEM part numbers 708-1W-00030, 708-3S-00010, or HPV55 stamp. You can also send us your machine serial number for instant fitment verification.

Q2: My Komatsu PC75-3 excavator stalls the engine when digging. Will replacing the HPV55 pump solve it?
A: Yes, engine stalling is usually caused by a faulty pump regulator valve failing to stroke down under load. Installing our pre-calibrated PC75-3 pump restores correct engine power matching.

Q3: Is this Komatsu PC75-3 hydraulic main pump bench tested before shipment?
A: Yes, every single main pump undergoes a 5-step factory bench test, verifying pressure up to 280 Bar and volumetric efficiency above 95%. A live test video is provided before shipping.