مضخة هيدروليكية Nachi PVD-2B-42 4310048 لـ حفارة صغيرة Hitachi EX55UR

EX55UR Hydraulic Pump for Excavator spare parts 4310048 PVD‑2B‑42 Axial Piston pump Aftermarket

Product Overview

This high‑performance aftermarket variable axial piston pump serves as the core hydraulic power source for Hitachi EX55UR compact crawler excavator. Built with integrated pilot pump assembly, this unit supplies pressurized hydraulic oil to fulfil boom lifting, arm dumping, bucket breakout, crawler travelling and upper‑body slew movements. Widely deployed in narrow‑space construction scenarios such as urban pipe trenching, backyard renovation, landscape reshaping and indoor demolition work. This 5‑ton mini excavator often operates under frequent start‑stop cycles and fluctuating load conditions. Over long service hours, contaminated hydraulic fluid and thermal fatigue will gradually wear cylinder block, piston shoe assemblies, valve plate and drive shaft. Common failure symptoms include insufficient digging force, jerky combined movements, distinct buzzing noise around pump compartment, continuous hydraulic oil temperature rise and external seal oil seepage. Manufactured strictly in accordance with original sample dimensions and hydraulic curve parameters, this aftermarket pump supports direct drop‑in replacement, helping repair shops and equipment owners restore machine working efficiency without bearing the high cost of genuine OEM assemblies.

Core Advantages

1. Optimized friction pair for narrow‑site mini‑excavator heavy‑load operations
Key mating components including cylinder block, piston shoes and valve plate adopt premium alloy material and multi‑phase heat‑treatment process. Precision grinding strictly controls internal fitting clearance, effectively lowering internal leakage and unstable flow fluctuation. Great anti‑cavitation capability enables stable operation even when hydraulic oil contains tiny impurity particles, slowing component aging under muddy, dusty construction surroundings.

2. Pre‑commissioned regulator for sensitive load response
Each finished pump undergoes full pressure‑flow debugging on professional hydraulic test bench. Regulator setting parameters keep highly consistent with original standards, which can rapidly respond to load variation during digging cycles. The built‑in pilot pump delivers steady control pressure for joystick manipulation, effectively eliminating operating jitter and slow action response caused by insufficient pilot pressure output.

3. Duplicated original mounting structure to cut on‑site repair downtime
Mounting flange dimension, spline shaft specification, oil port layout and regulator installation position are fully matched with original parts. Maintenance technicians can finish pump swapping without adjusting pipelines or resetting complex hydraulic system parameters. For rental fleets and local repair garages, it greatly shortens machine idle period and reduces economic loss caused by equipment stand‑still.

4. Reinforced housing and multi‑layer sealing protection system
Integral high‑density cast iron housing absorbs pressure impulse and mechanical vibration generated during frequent excavation cycles. High‑grade combined sealing kits block high‑pressure hydraulic oil outward leakage, and meanwhile stop mud, grit and moisture from entering pump inner chamber, preventing secondary abrasive damage to internal precision parts.

5. Cost‑effective maintenance solution for compact excavator operators
Genuine original main pump features high purchase price and long procurement lead‑time. This aftermarket pump provides dependable comprehensive performance at competitive cost, making it the preferred spare‑part option for repair workshops, equipment rental firms and global mini‑excavator spare‑parts distributors.

Manufacturing & Quality Control

Our production workshop is dedicated to aftermarket hydraulic pump manufacturing for Hitachi small‑tonnage excavators. Full‑process quality supervision runs through every production step: incoming raw‑material inspection, heat‑treatment hardness verification, key dimension measurement, assembly check and finished‑product hydraulic bench test covering pressure‑holding, flow output, noise detection and cyclic load simulation. Only fully qualified units can proceed to packaging procedure. Completed pumps are coated with anti‑rust preservation oil, wrapped with shock‑absorbing cushion material and packed in export‑grade fumigated wooden cases to avoid scratch, deformation and rust damage during long‑distance sea‑land transportation. We support bulk wholesale, stable batch supply, small trial orders are acceptable for worldwide buyers.

Frequently Asked Questions

Q1: What abnormal conditions mean main pump inspection or replacement is needed?
A: If your Hitachi EX55UR excavator suffers weak digging capacity, sluggish compound movements, obvious abnormal noise near main pump, fast hydraulic oil overheating, or metallic powder is found inside hydraulic filter element, you need to carry out system pressure test and pump disassembly inspection timely.

Q2: Will this hydraulic pump fit other Hitachi excavator models?
A: This assembly is specially manufactured for Hitachi EX55UR. Mini‑excavator main pumps differ greatly in displacement, spline size and internal regulator construction. Please double‑check your original part number 4310048 and PVD‑2B‑42 before placing order to avoid installation mismatch.

Q3: Which critical points should be highlighted during installation work?
A: Thoroughly clean hydraulic oil tank, pipelines and oil cooler, fit brand‑new hydraulic oil and all filter cartridges. Keep assembling environment clean to prevent contaminants entering pump inner cavity. After installation completion, finish hydraulic system air exhaust and low‑speed no‑load running test before putting machine into formal construction work.

Q4: Warranty scope description
A: Our warranty covers defects caused by manufacturing flaws. Damage triggered by contaminated hydraulic oil, improper installation, cavitation corrosion and long‑time overload service is not included within warranty coverage. Please strictly follow Hitachi official maintenance manual during overhaul work.