31Y1-09990 Boom Cylinder Seal Kit for Hyundai R250LC-7 Excavators Repair
31Y1-09990 Seal Kit Product Overview
The 31Y1-09990 Boom Cylinder Seal Kit is authentic fit for Hyundai R250LC-7 excavators boom cylinder repairs. This repair kit restores factory sealing integrity to eliminate boom drift, internal leaks, and pressure loss in heavy-duty digging operations. Includes all components specified in Hyundai Technical Bulletin HTB-EX07-19.
The Boom Seal Kit Specifications
| Compatible Models | Hyundai R250LC-7 |
| Cylinder Bore/Rod | 145mm (5.71″) / 110mm (4.33″) |
| Pressure Rating | 31.4 MPa continuous │ 36.5 MPa dynamic peak |
| Temperature Range | -30°C to +105°C (-22°F to +221°F) |
| Seal Material | Nitrile Rubber (NBR70) + Polyurethane |
The Seal Kit Contents
| Double-Acting U-Cup Seal | Main pressure seal (PU) |
| Step Seal (NBR70) | Rod leak prevention |
| PTFE Guide Band | Reduces friction (CoF: 0.028) |
| Triple-Lip Wiper | Excludes >20μm contaminants |
| Anti-Extrusion Ring | Prevents seal failure at 36.5 MPa peaks |
| HN90 O-Rings | Static seal corrosion resistance |
| Matches Hyundai Drawing HSD4-BOOM-SK07 | |
Key Benefits
✅ Zero Boom Drift: Maintains pressure at 31.4 MPa (KS B 0814:2015 validated)
✅ 3,000+ Hour Lifespan: PTFE components resist abrasion in demolition debris
✅ Coastal Operation Ready: HN90 seals withstand saltwater corrosion
✅ Arctic Performance: -30°C flexibility with HAC-LT-2 hydraulic oil
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].
