ZX330-3 ZX350-3 4438338 4642947 HPV145 Hydraulic Pump Repair Kit Compatible with Hitachi

1. Product Overview & Wholesale Price Range

The Hitachi HPV145 Hydraulic Main Pump Repair Kit (OEM Part # 4438338 / 4642947 / HPV145) includes the complete internal rotary group overhaul set: cylinder block, piston shoes with bronze slippers, distributor valve plate (RH/LH), retainer plate, ball guide, swash plate cradle, drive shaft, and coil springs designed for 30-to-35-ton excavators undergoing main pump overhauls.

• Factory Wholesale Price: $380 – $850 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 Cradle (1pc)
• 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 hydraulic working pressure across demanding 30-35 ton excavator jobsites:

• Heavy Open-Pit Mining & Quarrying: Restores maximum hydraulic pressure up to 350 Bar during continuous rock loading with Hitachi ZX350-3 excavators.
• Deep Foundation Excavation & Earthmoving: High thermal resistance bimetallic plates prevent power loss during continuous long-hour digging.
• Highway Infrastructure & Utility Trenching: Precision lapped cylinder faces ensure zero internal oil bypass during fast bucket loading cycles.
• Demolition & Heavy Breaker Operations: Case-hardened steel pistons withstand continuous high hydraulic pressure spikes from hammer attachments.

3. Hydraulic Pump Overhaul & Fault Diagnostic Guide (维修包常见故障排查)

If your Hitachi ZX330-3 / ZX350-3 excavator main pump is exhibiting performance degradation, check the wear symptoms below:

• Fault 1: Thermal Pressure Loss & Machine Slowdown After 1 Hour (热车掉压发慢/内泄)
  Root Cause: Wear gap between the cylinder block face and valve plate surface causing internal high-pressure thermal oil bypass.
  Solution: Replace the worn rotary group with our precision lapped HPV145 cylinder block and valve plate kit (OEM 4438338).
• Fault 2: Engine Stalls or Lacks Digging Force Under Heavy Bucket Load (憋车熄火/无力)
  Root Cause: Scoring on piston shoe brass slippers or stickiness in the swashplate cradle pivot.
  Solution: Install new HPV145 copper-coated piston shoes and swashplate group to restore smooth stroke control.
• Fault 3: Black Copper Filings Found in Hydraulic Tank 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 system, clean main control valve, and rebuild pump with a new HPV145 repair kit.
• Fault 4: Abnormal Pulsation Noise & Chattering From Pump Housing (泵体异响/震动)
  Root Cause: Broken retainer plate spring, worn ball guide, or pitted swashplate surface.
  Solution: Replace ball guide, retainer plate, and swashplate assembly to eliminate mechanical chatter.

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 HPV145 repair kit fits my Hitachi ZX330-3 or ZX350-3 excavator main pump?
A: Check your original pump nameplate for OEM part numbers 4438338, 4642947, or HPV145 stamp. You can also send us photos of your old cylinder block and pistons for instant fitment verification.

Q2: What is the material composition of the HPV145 cylinder block and piston slippers?
A: Our HPV145 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 HPV145 repair kit a complete overhaul solution for main pump rebuilds?
A: Yes, it includes all major internal wear components (cylinder block, 9 pistons, valve plate, retainer plate, ball guide, and swashplate) required for a complete pump rebuild.