4364912 Boom Cylinder Seal Kit for Hitachi Excavator EX120 EX130H EX135UR EX140US Series
4364912 Boom Cylinder Seal Kit Product Overview
The 4364912 Boom Cylinder Seal Kit is precision-engineered hydraulic solution for Hitachi excavators EX120-140 Series repair, this Hitachi seal kit eliminates hydraulic drift, external leaks, and jerky boom movements.
4364912 Seal Kit Technical Specifications
| Compatible Models | EX120 • EX120-3 • EX130H • EX135UR • EX140US |
| Cylinder Type | Boom (Arm) Cylinder repair |
| Rod Size | Ø75mm (2.95″) ±0.01mm |
| Bore Size | Ø100mm (3.94″) |
| Operating Pressure | 32 MPa (4,642 PSI) continuous │ 40 MPa peak |
| Temp. Resistance | -25°C to +110°C (-13°F to +230°F) |
| Seal Materials | EU80 Polyurethane (hydrolysis-resistant) NBR70 O-rings (cold-flex optimized) |
The Seal Kit Contents
| 3-Point Buffer Seal (EU80) | Absorbs shock pulses during trenching |
| U-Cap Piston Seal | Zero-leak design @ 40 MPa peaks |
| Multi-Lip Wiper (4X) | Excludes 99.7% contaminants >15μm |
| Rod Scraper (HNBR) | Prevents scoring on chrome-plated rods |
| Wear Band (PTFE + Glass) | Low-friction (CoF ≤0.03) guides |
| Anti-Extrusion Rings (POM) | Prevents seal deformation during side-loads |
| Static Seals (NBR70) | Gland/cap seals (-25°C flexibility) |
Performance Advantages
✅ Zero Boom Sag After 24hrs: <1.2° position drift under 5-ton load
✅ Hammer Duty Ready: EU80 compound withstands 40 MPa shock from hydraulic breakers
✅ Wear Reduction: Glass-reinforced PTFE bands extend cylinder life by 50% vs. nylon
✅ Chemical Resistance: Fully compatible with Hitachi BIO HF-2/ISO VG 46 fluids
Frequently Asked Questions (FAQ)
Q: Do you have any other excavator model repair seal kits ?
A: Yes. As the professional excavator seal kits manufacturer, we produce all the excavators repair seal kits, standard sizes and also support customization. Please tell us the part number seal kit you want.
Q: I can’t find the model I want. Are all your seal repair kits here?
A: No. We have more than tens of thousands seal kits. Here only a small part of them is shown. We have stock of all the seal kits for construction machinery. Please contact us!
Contact Us
For more information or to request a quote, please contact us or email [email protected].
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