Product Overview

The 4640107 boom cylinder seal kit is an aftermarket hydraulic seal kit for the boom cylinder of Hitachi ZX330-class excavators. Multiple independent suppliers – on Alibaba, eBay and dedicated excavator parts sites – list 4640107 for the boom cylinder (left-hand and right-hand) of the ZX330, ZX350H and ZX370 machines, with ZX350K and ZX360W-3 also named on the Alibaba listing. DJF Seals manufactures this kit factory-direct for wholesalers and repair workshops that maintain 30-tonne-class Hitachi excavators.

The boom cylinder lifts and holds the entire front attachment, so a worn sealing set shows up as boom drift, oil loss and reduced lifting force. A matched reseal restores holding power and keeps the cylinder bore clean.

Verified Application

Model note: the DJF listing writes ZX330 / ZX350 / ZX360 / ZX370 with LC/H/K variants. Independent references name ZX360W-3 rather than a plain ZX360; if your machine is a plain ZX360, confirm the cylinder part number before ordering.

Replacement Scope

The kit is intended to replace the complete sealing set of one boom cylinder: rod seal, piston seal, wiper, guide/wear rings and static O-rings. On the 30-tonne class, boom cylinders work under sustained high pressure with heavy side loads, so the guide elements and seals have to resist both extrusion and abrasion.

Distributor listings describe the 4640107 kit for the boom cylinder on the left-hand or right-hand side of the machine – order one kit per boom cylinder being rebuilt. Exact component quantities are confirmed against your cylinder at order time.

Fitment Verification

• Confirm the cylinder position: boom cylinder (LH or RH).
• Confirm the machine model against the verified list above (ZX330 / ZX350H / ZX350K / ZX360W-3 / ZX370MTH and related variants).
• If your machine is a plain ZX360 or another variant, provide the stamped cylinder part number with your inquiry.

Factory Inspection & Packing

Kits are built in our own factory from compound-checked seal batches, gauged against the 4640107 picking list, and packed with the sealing lips protected. Each pack is labelled with the part number and ships in reinforced cartons with the packing list, ready for air, sea or express freight.

Wholesale Ordering

DJF supplies the 4640107 boom seal kit factory-direct to excavator parts distributors and large repair companies. Direct-from-manufacturer sourcing gives you full production quality control, competitive bulk pricing and the option to consolidate with other Hitachi ZX-series kits (boom, arm, bucket) in one container.

Minimum Order Quantity (MOQ)

MOQ: 5 kits. We accept single-kit trial orders for fitment testing, with tiered wholesale pricing at volume. Contact our export team for the current MOQ, price breaks and lead time for 4640107.

FAQ

Q: Which Hitachi machines does the 4640107 kit fit?

A: Independent listings confirm the boom cylinder of ZX330, ZX350H, ZX350K, ZX360W-3, ZX370MTH and ZX350LC machines. The DJF page lists ZX330 / ZX350 / ZX360 / ZX370 LC-H-K variants; plain ZX360 was not named by independent sources.

Q: Is one kit enough for both boom cylinders?

A: Listings describe the kit for the boom cylinder (LH/RH), i.e. one kit rebuilds one boom cylinder. Order one kit per cylinder you plan to rebuild.

Q: What are the rod and bore sizes?

A: The DJF listing states rod 105 mm and bore 150 mm. These are manufacturer-listed values; measure your boom cylinder or send the cylinder number so we can confirm the match.

Q: Can I use 4640108 instead?

A: No. 4640108 is listed by suppliers as a bucket cylinder kit for the ZAX330-6 / ZX450H combination – a different cylinder position. Use 4640107 for the boom cylinder and ask us for the correct bucket kit separately.