Boom Cylinder for Caterpillar Large Excavator E336D
Boom Cylinder for Caterpillar Large Excavator E336D

The Caterpillar large E336D excavator boom cylinder is a precision-replacement hydraulic cylinder engineered for direct OEM-fit installation on Caterpillar large excavators. This Caterpillar boom cylinder matches the original bore diameter, stroke length, rod specification, port thread, and mounting pin geometry of the Caterpillar OEM component, ensuring direct-fit compatibility without modification to the Caterpillar E336D excavator hydraulic circuit or attachment structure.

Key Technical Facts
- ✦ Cylinder type: Boom cylinder for Caterpillar large excavator E336D — double-acting, OEM-fit replacement
- ✦ Bore range: 160–250 mm — rod diameter 115–180 mm, working pressure 30–35 MPa
- ✦ Stroke range: 1,300–1,800 mm — push force 603–1,718 kN at max pressure
- ✦ Seal package: PU rod seal + NBR piston seal — High-pressure large-bore compound, compatible with ISO VG 46–68 mineral oil
- ✦ Manufacturing standard: Bore H8 tolerance, rod Ra ≤ 0.2 μm hard chrome, 100% pressure test at 1.5× rated pressure
- ✦ Supply: 3–7 working days standard catalog sizes · Custom bore-stroke 15–25 working days · ISO 9001:2015
Caterpillar Large Excavator Boom Cylinder — Technical Overview
On the Caterpillar large excavator E336D, the boom cylinder connects the between the upperstructure and large boom on paired mounting and delivers support and elevate the full boom assembly under maximum load under high sustained pressure with dynamic crowd loading during production digging loading conditions. Caterpillar designs its excavator hydraulic circuits for high-cycle reliability: the boom cylinder must maintain consistent bore geometry, rod surface finish, and seal integrity across tens of thousands of operating hours. Our replacement Caterpillar boom cylinder is manufactured to these same OEM dimensional and surface-finish standards.
Internal bypass in a Caterpillar E336D boom cylinder — where hydraulic oil transfers from the cap-end chamber to the rod-end chamber past the piston seal — reduces available crowd force and increases cycle time. A 10% bypass loss on a Caterpillar mid-range excavator boom cylinder reduces bucket penetration force by approximately the same proportion, reducing dig productivity. Our piston seals use PU compound with controlled interference fit to the bore, maintaining effective sealing at pressures from 5 MPa to 35 MPa across the operating temperature range.
For a complete listing of Caterpillar excavator boom cylinders, see our boom cylinder category page. Technical guidance on identifying which components are failing is in our hydraulic cylinder bypass diagnostic guide.

OEM Compatibility — Caterpillar E336D: This boom cylinder is manufactured to match the Caterpillar OEM bore, stroke, rod diameter, port thread standard, and mounting pin geometry for the E336D series. The replacement Caterpillar boom cylinder installs directly into the Caterpillar E336D excavator without machining, shimming, or modification. Provide the Caterpillar OEM part number when ordering for dimensional verification before despatch. Non-standard Caterpillar E336D variants — including long-reach and heavy-lift arm configurations — are available as custom-manufactured units within 15 to 25 working days.

OEM vs Replacement — Caterpillar Excavator Boom Cylinder Comparison
Seal Package — Caterpillar E336D Boom Cylinder

The Caterpillar E336D boom cylinder seal package consists of: a PU (polyurethane) rod wiper seal that excludes abrasive particles from the chrome rod surface on retraction; a primary PU or NBR rod seal that retains hydraulic oil under working pressure; NBR O-rings at the port fittings and end-cap interface; and a polyurethane piston seal that maintains the pressure differential between cap-end and rod-end chambers. Standard seals are rated for mineral hydraulic oil (ISO VG 32–68) at −20 °C to +80 °C continuous operation. For cold-climate Caterpillar excavator operation below −20 °C, specify PU/NBR-55 low-temperature compound. For high-temperature or fire-resistant fluid applications, FKM (Viton) seals are available on request. The full seal kit for the Caterpillar E336D boom cylinder is available separately — contact us with the Caterpillar OEM part number to verify compatibility. See our hydraulic cylinder parts and seal guide for further information on seal selection.

Step 1 — Identify cylinder position: boom cylinder (between the upperstructure and large boom on paired mounting)
Step 2 — Locate OEM part number: stamped on cylinder barrel or listed in Caterpillar E336D service manual
Step 3 — If part number not available: measure bore diameter (inside barrel), rod diameter (chrome surface),
stroke length (extended minus retracted), and collapsed length (pin-to-pin fully retracted)
Step 4 — Verify pin diameters at cap end and rod end — note mounting style (pin-eye, clevis, flange)
Step 5 — Submit OEM part number or measurements — receive compatibility verification and price within 24 hours
Caterpillar Boom Cylinder — Specification Reference:
Bore range: 160–250 mm Rod diameter: 115–180 mm
Stroke range: 1,300–1,800 mm Working pressure: 30–35 MPa
Push force: 603–1,718 kN at max working pressure
Application Areas — Caterpillar Excavator Boom Cylinder
Verify dimensions before ordering: Caterpillar excavator boom cylinders vary in bore, stroke, rod diameter, and pin geometry between model series and production years. Always supply the Caterpillar OEM part number or a full dimensional drawing to verify correct supply. Our engineering team verifies compatibility against Caterpillar dimensional data before processing every order.
When to replace vs reseal: Reseal the Caterpillar E336D boom cylinder when rod seal leakage is present but the chrome rod surface is undamaged (no pitting, scoring, or peeling). Replace the full cylinder if: (1) chrome rod shows scoring deeper than 0.3 mm; (2) bore is out-of-round beyond 0.05 mm; (3) cylinder fails to hold load under pressure (internal bypass); or (4) barrel shows bending or weld failure. A damaged chrome rod will destroy any new seal set within 200 to 500 operating hours.
Installation Guidelines — Caterpillar E336D Boom Cylinder
When replacing the boom cylinder on a Caterpillar E336D excavator, lower all attachments to the ground and engage the hydraulic lock before beginning work. Relieve residual pressure by moving all control levers with the engine off. Label hydraulic hose connections before removal — cap-end and rod-end port connections must be reinstalled correctly on a double-acting boom cylinder. Fit the replacement Caterpillar boom cylinder with both mounting pins greased and retention hardware in place. After hydraulic reconnection, inspect all port connections for thread engagement before starting the engine.
For pre-replacement diagnostics on the Caterpillar E336D, refer to our cylinder bypass diagnostic guide. Review our manufacturing quality standards for full details of our production and testing process.
Manufacturing Capability: Ever-Power Huachang

Our Caterpillar excavator boom cylinder range is one of our core product lines, with stock maintained for all standard Caterpillar E336D sizes. Ever-Power Huachang operates a 60,000 m² manufacturing facility in Hangzhou, China, certified to ISO 9001:2015, ISO 14001:2015, and ISO 45001:2018. The Caterpillar boom cylinder production cell includes CNC boring machines, external cylindrical grinding, automated chrome plating, controlled seal assembly stations, and a dedicated pressure-test bay. Our 3,000+ completed projects across construction, mining, and infrastructure sectors include long-term supply agreements with major equipment rental fleets.
Learn more about our manufacturing facility and engineering team on our company capability page.
Frequently Asked Questions: Caterpillar E336D Boom Cylinder
Caterpillar Excavator Cylinder — OEM Replacement Program
Request a Quote — Caterpillar Excavator Boom Cylinder
Submit your Caterpillar E336D boom cylinder requirement with model number or dimensional drawing. Volume pricing applies for orders of five or more units. Response within 24 hours from our engineering sales team.
✉ დაგვიკავშირდით · წარმოების შესაძლებლობები · ISO 9001:2015 · 3–7 day standard lead time · 60+ countries served




