Parameters

Dimensions are typical reference values. Please confirm exact bore, rod, stroke, and mounting dimensions by machine serial number before ordering.

Product Technology

This arm cylinder is manufactured with advanced CNC machining and precision heat treatment. The barrel is skived, roller burnished, and diamond-honed to Ra 0.2–0.4 μm, reducing friction and internal leakage. The piston rod is centerless ground, hard chrome plated, and polished for superior wear resistance. Ultrasonic inspection ensures zero material defects. Every cylinder is pressure tested to 1.5 times maximum working pressure before shipment.

Product Applications

• Doosan DH300 Excavator: Direct replacement for the OEM arm cylinder on standard configurations.

• 30-Ton Excavator Fleets: Ideal for construction, utility, and general earthmoving machines.

• Construction & Earthmoving: High-production digging, trenching, loading, and site preparation.

• Rental & Repair Shops: Perfect for rebuilding Doosan DH300 machines or replacing worn cylinders.

• Agricultural & Municipal Work: Reliable performance for ditching, grading, and material handling attachments.

Manufacturing Process

1. Raw Material Sourcing: High-tensile seamless steel tube and 40Cr alloy steel for the rod with full material certificates.

2. Barrel Preparation: Tube is cut to length, skived, and roller burnished for a smooth work-hardened inner surface.

3. Honing: Diamond honing achieves final bore tolerance and surface finish (Ra 0.2–0.4 μm) for optimal sealing.

4. Rod Machining: Rod blank is turned and centerless ground to precise diameter and straightness.

5. Chrome Plating: Hard chrome plated to 0.03–0.05 mm and polished to mirror finish with HRC 58–62 hardness.

6. Port & Clevis Welding: TIG-welded ports and clevis ends, then stress-relieved.

7. Assembly: Piston, seals, rod, and end caps assembled in a clean environment with verified torque settings.

8. Pressure Testing: Each cylinder tested at 480 bar (1.5x working pressure) for leakage and structural integrity.

9. Painting & Packaging: Anti-corrosion industrial paint applied, packed in a wooden crate with desiccant for ocean transport.

FAQ – Doosan DH300 Arm Cylinder Assembly

Q1: How do I confirm this cylinder fits my Doosan DH300?
This arm cylinder is manufactured to match the OEM specifications for the Doosan DH300 / DH300LC-7. Verify your machine’s serial number and compare pin-to-pin closed length and port size with the table above. Send us a photo of your old cylinder’s data plate if unsure, and we will confirm compatibility before you order.
Q2: What is the expected service life?
Under normal operating conditions with proper hydraulic oil maintenance, expect 6,000–10,000 working hours before seal replacement or rebuild. Heavy digging cycles, contaminated oil, or excessive sideloading can shorten this interval.
Q3: Can I install this cylinder myself?
Yes, installation is straightforward for an experienced mechanic. Park the machine on level ground, release hydraulic pressure, disconnect hoses, remove retaining pins, and lift out the old cylinder. Install the new one in reverse order. Always bleed the system and check for leaks before full operation. Video call support is available 24/7.
Q4: Do you provide a seal kit for this cylinder?
Yes, complete seal kits matched to this DH300 arm cylinder are in stock. Kits include piston seals, rod seals, wipers, O-rings, and backup rings. Replace the seal kit every time you disassemble the cylinder.
Q5: What causes arm cylinder failure and how can I prevent it?
Common causes include contaminated hydraulic oil, bent rods from sideloading or overloading the arm, and neglected seal replacement. Change hydraulic oil and filters on schedule, avoid using the arm as a lever or hammer, and regularly inspect the rod for scratches or chrome damage.
Q6: Is this a genuine Doosan part?
This is a high-quality aftermarket replacement manufactured to OEM specifications, not a genuine Doosan component. It is designed and tested to match or exceed OEM performance at a lower price. Many repair shops and fleet owners choose our cylinder for reliability and cost savings.
Q7: Can you customize stroke or mounting dimensions?
Yes, we offer custom configurations. If your DH300 has modified linkage or requires non-standard stroke or pin sizes, contact our engineering team with your requirements. We can adjust bore, rod, stroke, and mountings to fit your application.