SY35C SY35U SY30U 11422787 60021663 K3SP36C Hydraulic Main Pump Assembly Compatible with Sany

1. Product Overview & Wholesale Price Range

The Sany SY35C / SY35U K3SP36C Hydraulic Main Pump Assembly (OEM Part # 11422787 / 60021663 / K3SP36C / PSVD2-17E) is a compact variable displacement axial piston pump engineered for 3.5-to-4-ton mini hydraulic excavators working in tight urban trenching, landscaping, and foundation digging applications.

• Factory Wholesale Price: $780 – $1,650 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 flow control designed to deliver smooth hydraulic power across compact excavator jobsites:

• Urban Utility Trenching & Cable Laying: Fine hydraulic metering for smooth bucket and arm control in narrow ditches with Sany SY35C zero-tail excavators.
• Residential Landscaping & Lawn Grading: Consistent hydraulic flow under continuous swing and travel cycles for earth leveling and tree planting.
• Agricultural Irrigation & Farm Maintenance: Thermal-resistant seal groups prevent oil bypass during long continuous operating hours in hot weather.
• Building Renovation & Small Concrete Breaking: Compact pump casing built to absorb pressure shockwaves caused by hydraulic hammer attachments.

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

If your Sany SY35C mini 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 K3SP36C main pump assembly (OEM 11422787) 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: K3SP36C pump regulator control spool jammed or pilot pressure relief 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 Sany SY35C 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 Sany SY35C or SY35U mini excavator?
A: Check your original pump nameplate for OEM part numbers 11422787, 60021663, or K3SP36C stamp. You can also send us your machine serial number for instant fitment verification.

Q2: My Sany SY35C excavator stalls the engine when digging. Will replacing the K3SP36C pump fix this?
A: Yes, engine stalling is usually caused by a sticking pump regulator valve failing to de-stroke under load. Installing our pre-calibrated Sany SY35C pump restores smooth engine power matching.

Q3: Is this Sany SY35C hydraulic main pump bench tested before shipment?
A: Yes, every single K3SP36C pump undergoes a 5-step factory bench test, verifying pressure up to 250 Bar and volumetric efficiency above 95%. A live test video is provided before shipping.