707-99-58080 Boom Cylinder Seal Kit for Komatsu PC300-7 PC300LC-7 Excavator
707-99-58080 Seal Kit Product Overview
The 707-99-58080 Seal Kit is a genuine Komatsu OEM replacement for boom cylinder repairs on Komatsu PC300-7 and PC300LC-7 excavators. Engineered to exact factory specifications, this kit restores hydraulic integrity in high-pressure boom systems (up to 34.3 MPa/4,975 PSI), eliminating leaks and restoring lifting performance. Includes all critical components validated by Komatsu Engineering Standard KES 07.340.
707-99-58080 Boom Cylinder Seal Kit Technical Specifications
| Application | Komatsu PC300-7/PC300LC-7 Boom Cylinder Repair |
| Rod Size | 100mm (3.94″) | Bore: 140mm (5.51″) |
| Pressure Rating | 34.3 MPa continuous / 40 MPa peak |
| Temperature Range | -40°C to +110°C (-40°F to +230°F) |
| Material | Cast Polyurethane (PU) seals + PTFE-reinforced nylon |
| Compatibility | Komatsu BIO HF-2/HF-3 hydraulic fluids |
The Excavator Seal Kits Included
| PU U-Cup Seal | Primary pressure sealing |
| Triple-Lip Wiper | Purple PU; filters >15μm contaminants |
| PTFE Buffer Rings | Prevents seal extrusion |
| HNBR O-Rings | Fluid-resistant static seals |
| Bronze-PTFE Guide Band | Reduces rod scoring |
| Matching Komatsu drawing K3VG-BOOM-02 | |
Key Benefits
- Factory Performance Restoration
- Stops boom drift & leakage with OEM-spec dimensional tolerances (±0.02mm).
- Extended Service Life
- PTFE components provide 3,000+ hour lifespan in abrasive environments.
- Cold-Weather Reliability
- -40°C flexibility prevents brittle fractures (tested per JIS B 2401:2019).
- Reduced Downtime
- Complete gland rebuild in <2 hours with torque specs included.
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!
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