Wholesale Excavators Parts Hydraulic Stick Arm Cylinder Compatible with Kobelco
Heavy-duty arm cylinder engineered for Kobelco excavators. Built from high-strength alloy steel with a CNC-machined piston rod and barrel, this cylinder ensures accurate control, smooth reach operation, and reliable hydraulic performance in daily trenching and grading tasks.
| Cylinder Tube | Q345 / ST52 / 27SiMn / 20# Steel |
|---|---|
| Piston Rod | 45# / 40Cr / 42CrMo (Hard Chrome Plated) |
| Piston | Ductile Iron / Forged Steel (45# / 20Cr) |
| Cylinder Head | Q345 / 45# Steel / Cast Steel |
| Seals | Polyurethane (PU), NBR, FKM |
| Guide Bush | Bronze Alloy / Composite Materials |
| Ports & Fittings | Zinc-Plated Carbon Steel / Stainless Steel |
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Kinton Parts is trusted by professionals worldwide for delivering high-quality parts for excavators, bulldozers, and other construction machinery—with guaranteed performance and durability.
The arm cylinder—also referred to as the stick cylinder—links the boom to the arm and controls forward digging, slope finishing, and material handling reach. In Kobelco excavators such as SK210LC, SK260, and SK330LC, it is responsible for:
- Maintaining precise bucket reach and angle
- Delivering force during trenching or soil compaction
- Absorbing recoil forces when the bucket hits rocks or compacted layers
This cylinder must endure bidirectional hydraulic loads, lateral pivot stress, and continuous movement cycles—making structural durability and sealing reliability essential.
Material Quality and Structural Design
Each Kobelco arm cylinder is manufactured using carefully selected raw materials and machining processes that meet or exceed OEM standards:
- Rod: Made of 42CrMo alloy steel, chrome-plated (≥25μm) and polished for wear resistance
- Barrel: Seamless Q345B / 27SiMn / ST52 steel tube, honed internally to < Ra 0.2μm
- End Cap & Piston: CNC-machined for precise tolerance and concentricity (within ±0.05mm)
- Bushings: Available with hardened grease grooves or replaceable sleeves based on customer request
Features
- High tensile strength and anti-fatigue performance
- Welded or bolted ends with eye/clevis options
- Pre-installed steel backing rings to prevent extrusion under pressure
Internal Cross-Sectional Diagram
This diagram helps visualize how the rod, piston, barrel, and seals interact under pressure, showing key wear zones and sealing points for effective maintenance planning.
Cylinder Manufacturing Process
We follow strict quality workflows, and you can visually demonstrate the process using three key production images：
Rod Polishing & Surface Prep
The piston rod is ground and polished to achieve a mirror-smooth surface, ready for hard chrome plating. This step reduces wear on seals and ensures long-lasting hydraulic performance.
Assembly & Sealing
In a cleanroom assembly area, the barrel, piston, rod, and end caps are fitted and torqued to spec. Seal kits are carefully installed to prevent fluid loss and contamination.
Pressure Testing & Export Packaging
Each cylinder is tested to withstand 1.5× working pressure and checked for leaks, stroke alignment, and valve performance. Final products are sealed and packed in export-grade wooden crates.
Finished products are sprayed with anti-rust coating and packed in export-grade wooden crates.
OEM Undercarriage Parts for Kobelco Excavator
| BRAND | MACHINERY MODEL NUMBER | |||||||
|---|---|---|---|---|---|---|---|---|
| KOBELCO | SK30 | SK35 | SK40 | SK45 | SK55 | SK60 | SK60-8 | SK60-10 |
| SK75 | SK100 | SK120 | SK120-5 | SK120-6 | SK130 | SK135 | SK135SR | |
| SK135SR-2 | SK140 | SK140SR | SK200 | SK200-3 | SK200-5 | SK200-6 | SK200-8 | |
| SK200-10 | SK210 | SK210-8 | SK210LC | SK220 | SK230 | SK230LC | SK250 | |
| SK250-8 | SK260 | SK260LC | SK270 | SK300 | SK300-6 | SK300-8 | SK320 | |
| SK330 | SK330-6 | SK350 | SK350-8 | SK350LC | SK380 | SK400 | SK450 | |
| SK480 | SK480-8 | SK485 | SK500 | SK500LC | SK850 | SK850LC | ||
Looking for a specific make or model not listed here? Reach out and we’ll be happy to assist.
Model Compatibility for Kobelco
This arm cylinder is suitable for a wide range of Kobelco excavators, including:
- SK200 / SK210 / SK210LC-8 / SK230 / SK250-8 / SK260LC
- SK300 / SK330-8 / SK330-10 / SK350LC / SK480LC
- SK230SR / SK350SRLC / SK260NLC
Don’t see your model listed? Send us your machine model, OEM number, or technical drawing, and we’ll confirm compatibility in 12 hours or less.
Maintenance Tips for Kobelco Arm Cylinders
- Inspect chrome rod for pits, corrosion, or bending every 500–700 hours
- Check for any oil seepage or wear marks around rod seal
- Lubricate pivot joints regularly to avoid bushing wear
- Avoid rapid full-stroke actuation under high-load conditions
SHIPPING & DELIVERY
At Kinton Parts, we ensure reliable, worldwide shipping of parts for excavators, bulldozers, and a full range of construction machines—safe, fast, and secure.
All products are securely packed using high-quality export cartons, reinforced wooden cases, or industry-standard palletized packaging to ensure maximum protection during transit and smooth handling during unloading.
Standard orders are typically shipped within 3–5 working days, while large or customized orders are usually dispatched within 7–20 days, depending on volume and production requirements.
We offer flexible global shipping options, including:
- International sea freight for cost-effective bulk transport
- Air freight for urgent orders
- Courier delivery (DHL, FedEx, UPS) for small-volume or sample shipments
Our logistics team manages every shipment carefully, providing real-time updates and tracking information until your order arrives safely at your destination.
Need assistance choosing the best shipping method for your location and timeline? Contact our team — we’ll help you plan a smooth delivery experience.
FAQ
Q: What are your main products?
A: We supply a full range of undercarriage and wear parts for excavators, bulldozers, and other heavy equipment. Our product line includes: Track rollers, carrier rollers, front idlers, sprockets, segments, track shoes, track chains, bolt and nuts, pins and bushings, bucket teeth and adaptors, filters, seal kits, swing bearing, and hydraulic cylinder—plus other essential replacement parts.
Q: Which countries do you export to?
A: Kinton Parts exports to over 60 countries worldwide, including:
USA, Canada, UK, Germany, Russia, UAE, Indonesia, Malaysia, Thailand, India, Pakistan, Bangladesh, Sri Lanka, South Africa, Colombia, Peru, and many others.
Q: Can I order a sample?
A: Yes, we accept trial orders. For parts in stock, samples can be shipped quickly. If you have technical drawings or existing samples, we also support customized production and mold development.
Q: How can I track my order after shipping?
A: Once your order is shipped, we will provide you with all necessary tracking information based on the shipping method. For express deliveries, you’ll receive a tracking number to follow the shipment online. For air or sea freight, we’ll send you the relevant documents such as the airway bill (AWB) or bill of lading (B/L), along with the packing list and commercial invoice to help with tracking and customs clearance.
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Trusted by professionals worldwide, Kinton Parts supplies premium-quality components for excavators, bulldozers, and more—with reliable quality you can count on.
