Hitachi EX300-5 Hydraulic Main Pump – China Remanufactured

1. Key Features & Benefits

• Professional remanufacturing to Hitachi OEM standards – This main hydraulic pump has been fully disassembled, cleaned, crack‑inspected, and rebuilt in our ISO‑certified facility in China. All worn components – cylinder block, piston assemblies, valve plate, swashplate, bearings, and seals – are replaced with new, high‑quality parts. The result is a pump that delivers performance and reliability comparable to a new unit at a fraction of the cost.

• Original Hitachi tandem axial piston design – The EX300‑5 pump is a variable displacement double (tandem) axial piston pump combining two independent pumping sections in one housing. This design powers travel, swing, boom, arm, and bucket circuits independently, delivering smooth, coordinated multi‑function operation without internal flow loss – exactly as your machine performed when it left the factory.

• Restored 30‑ton class hydraulic power – After remanufacturing, this pump delivers rated working pressure up to 34.3 MPa (≈4,975 psi) and flow matched to the EX300‑5‘s Isuzu B-6SD1T engine (169 kW at 1,900 rpm). With a hydraulic system relief valve pressure of 4,980 psi and operating weight of 31 metric tons, your excavator regains full digging force, fast cycle times, responsive swing, and powerful travel.

• Integrated load‑sensing power control – The factory power control (load‑sensing) system is completely rebuilt. It continuously matches pump output to actual working demand, reducing fuel consumption, preventing engine stall under sudden load, and extending the life of the entire hydraulic system. The integral pilot gear pump is also fully remanufactured.

• Cost‑effective alternative to new genuine – A new Hitachi main pump for a 30‑ton excavator is a major investment. Our remanufactured pump gives you the same fit, form, and function at a significantly lower price, without sacrificing reliability. Each pump is dyno‑tested on a hydraulic test stand before dispatch.

• Direct bolt‑on replacement – Mounting flanges, drive shaft splines, and hydraulic port configurations are restored to original Hitachi specifications. No modifications, no adapters, no fabrication – your mechanic unbolts the old pump and bolts this one in. Compatible variants include EX300‑5, EX300LC‑5, EX300LCLL‑5, EX300LCLL‑5M, EX330LC‑5, EX350H‑5, EX350K‑5, EX370‑5M, EX370HD‑5 and EX385USR excavators.

• Pre‑shipment visual verification – We send you clear, high‑resolution photographs of the actual remanufactured unit (mounting flange, splines, port threads, castings, overall condition) before packing. You approve shipment – we never ship blind.

• Fast delivery – 5–8 working days from our Guangzhou warehouse. Monthly supply capacity of 300 units, available for single‑piece or bulk orders.

2. Applications

The remanufactured Hitachi EX300‑5 main hydraulic pump is ideal for 30‑ton class excavators used in the most demanding job sites:

• Heavy construction & infrastructure – Highway excavation, dam building, bridge footings, and large‑scale earthmoving projects. The restored tandem pump delivers simultaneous boom, arm, and travel power without internal leakage – no power fade, no sluggish response, even on long shifts. Urban development and road construction demand precise hydraulic control, and the load‑sensing system ensures smooth operation whether you‘re trenching near utility lines or working on highway shoulders.

• Quarrying & aggregates – Loading trucks, stockpile management, and material handling in abrasive dust conditions are routine in granite, limestone and basalt operations. New bearings, seals, and wear plates ensure the pump survives where worn units fail. Consistent flow and pressure mean faster cycle times and lower fuel consumption, directly impacting your cost per ton.

• Open‑pit mining support – Site cleanup, overburden removal, road maintenance, drainage works, and equipment pad grading. The pump’s load‑sensing control reduces fuel burn during light‑duty cycles, saving money over thousands of operating hours. In mining environments where dust and vibration are extreme, our remanufactured pump with new seals and bearings provides the reliability you need to keep production moving.

• Demolition & scrap processing – Shock loads and vibration are routine in demolition yards and metal recycling facilities. Our remanufacturing process replaces all wear components, restoring the pump‘s ability to withstand harsh, unpredictable conditions. The integrated power control prevents engine stall when impact loads spike, maintaining consistent attachment power for shears, pulverizers, and hammers.

• Forestry & land clearing – Steep slopes, fallen timber, hidden obstacles, and remote locations demand hydraulic components you can trust. The integral power control prevents engine stall under sudden load spikes, maintaining consistent hydraulic power for saws, grapples, and mulchers. New seals prevent moisture ingress that is common in wet forestry environments.

• Long‑reach & specialized applications – EX300‑5 Long Reach variants are used for river rehabilitation, coastal work, deep trench excavation, and batching plant responsibilities. The high-track models excel in quarry and mining environments with uneven terrain. A reliable main pump is essential for these specialized configurations where hydraulic demand varies constantly.

3. Why Choose Hongtengda Parts – Quality You Can Trust

At Hongtengda Parts, we have been remanufacturing hydraulic pumps for Hitachi excavators since 2001. We know that a main pump failure on your EX300‑5 stops your job site completely. Our remanufacturing process is not a “clean and reseal” – it is a factory‑grade restoration.

Our 6‑step remanufacturing process:

1. Complete disassembly – The pump is stripped down to individual components: cylinder block, piston assemblies, valve plate, swashplate, bearings, shaft, housing, and control valves.

2. Cleaning & crack inspection – All parts are thoroughly cleaned and inspected for cracks using dye penetrant testing on critical castings. Irreparable parts are scrapped.

3. Wear component replacement – All seals, O‑rings, bearings, and gaskets are replaced with new components. The cylinder block and valve plate are precision‑ground to restore flatness. Piston assemblies are matched as a set and replaced if worn. The swashplate surface is reconditioned.

4. Precision reassembly – Components are reassembled using OEM torque specifications. Clearance tolerances on the cylinder block / valve plate interface are verified using dial indicators.

5. Hydraulic test stand validation – The completed pump is mounted to a test stand and run through its full pressure and flow range. We verify operating pressure (up to 34.3 MPa), flow rate, case drain leakage, and load‑sensing control response. A test report is available upon request.

6. Final quality check & packaging – The pump is painted, fitted with protective port caps, and packed in a heavy‑duty wooden case for export.

Why our remanufactured pump outperforms cheaper “rebuilt” units:

• New bearings and seals – Many budget rebuilders reuse old bearings to save cost. We do not. All rotating components get new bearings – the single most important factor for pump longevity.

• Precision‑ground wear surfaces – The cylinder block and valve plate are re‑ground to restore flatness. A lapped surface is essential for low internal leakage. Without it, the pump will overheat and lose power within weeks.

• Full test report – Upon request, we provide a test report showing pressure, flow, case drain, and temperature measurements. You see the data before you buy.

What you are not buying: A used pump with new paint and a set of O‑rings. Our remanufactured pump is restored to meet or exceed OEM performance standards – at a price that makes sense for your EX300‑5.

• 25+ years of industry experience – Founded in 2001, we have remanufactured thousands of pumps for Hitachi, Caterpillar, Komatsu, Kobelco, Volvo, SANY, and many other brands.

• 90% stock availability – EX300‑5 main hydraulic pumps are in stock as remanufactured units, ready for dispatch from our Guangzhou warehouse.

• 24‑hour shipment – From our Guangzhou hub to your forwarder in 1 day; international orders shipped within 24 hours.

• Pre‑shipment visual verification – We never ship a pump blind. You receive clear photos of the actual unit before packing – you approve, we ship.

• Technical support – Send us your EX300‑5 machine serial number and a photo of the old pump. We confirm compatibility and provide installation guidance within 2 hours.

Send us your Hitachi EX300‑5 machine serial number and a photo of the old pump – we will verify fitment, provide a quote, and document our pre‑shipment inspection within 24 hours.

Critical installation tip for the EX300‑5 remanufactured pump:
– The case drain line must be clear and unrestricted. A blocked case drain will blow the shaft seal instantly on first startup.
– Before installing the remanufactured pump, flush the entire hydraulic system and replace all filters. Contaminants from the failed pump will destroy a remanufactured unit just as quickly as a new one.
– Use new O‑rings and sealing washers on every hydraulic connection. Reused seals guarantee leaks.
– After installation, run the engine at low idle for 2–3 minutes with the pump in neutral, then slowly cycle each function (boom, arm, bucket, swing, travel) to purge air from the system.
– Check pump alignment with the engine flywheel housing – misalignment causes premature bearing failure and shaft seal leakage.

Warranty note: Warranty period is 3 to 6 months depending on product details. We do not provide warranty service for original used or remanufactured parts. Our value is delivered up front: careful remanufacturing, thorough testing, and pre‑shipment visual verification. For customers who require a warranty‑covered option, we can quote new aftermarket units – ask our sales team.

The main hydraulic pump is the heart of your EX300‑5‘s hydraulic system. A reman pump is a transplant from a tired donor with unknown hours. Our remanufactured pump is restored to meet OEM performance standards – not with shortcuts, but with genuine factory‑grade restoration. Send us your EX300‑5 machine serial number – we will confirm compatibility and provide a quote within 24 hours.