31Y1-28960 Boom Cylinder Seal Kit 31Y128960 for Hyundai Excavators R210-9/R220-9/R235LCR-9
31Y1-28960 Seal Kit Product Overview
The 31Y1-28960 Seal Kit is the official Hyundai OEM solution for rebuilding boom cylinders on 5th-generation Hyundai excavators. Precision-engineered to restore hydraulic performance, this kit eliminates leaks, reduces boom drift, and withstands Hyundai’s high-pressure HSD control system (35.5 MPa peak pressure). Includes all components specified in Hyundai Technical Bulletin HTB-EX09-023.
31Y1-28960 Boom Cylinder Seal Kit Specifications
| Compatible Models | R210-9, R210LC-9, R220-9, R220LC-9, R235LCR-9 |
| Cylinder Type | Boom Cylinder |
| Rod Diameter | 105mm (4.13″) |
| Bore Size | 150mm (5.91″) |
| Pressure Rating | 30.4 MPa continuous │ 35.5 MPa dynamic peak |
| Temperature Range | -35°C to +115°C (-31°F to +239°F) |
| Material Standard | Nitrile Rubber + Polyurethane (Hyundai HVS-008) |
Seal Kits Contents
| Primary Seal | Quad-ring HNBR-90 (Fluid-resistant) |
| Buffer Ring | Glass-fiber PTFE (Anti-extrusion) |
| Triple-Lip Wiper | Black PU w/ dust exclusion grooves |
| Guide Band | Carbon-filled PTFE (Low friction coefficient: 0.025) |
| Static O Ring Seals | HNBR O-rings |
| match to Hyundai Assembly Drawing HSDE5-BOOM-SK01 | |
Certified Performance Advantages
✅ Zero Leak Guarantee
- Seals maintain integrity at 30.4 MPa continuous pressure
✅ 2.8x Longer Lifespan
- PU/NBR compound resists 5µm hard particle abrasion common in demolition work
✅ HSD Control Optimized
- Prevents boom chatter during precision grading (Compatible with HSD-5 hydraulic oil)
✅ Arctic Compliance
- -35°C flexibility validated at Hyundai
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].
