707-99-58080 Boom Cylinder Seal Kit for Komatsu PC300-7 PC300LC-7 Excavator | DJF Seal
707-99-58080 Boom Cylinder Seal Kit Product Overview
The 707-99-58080 Boom Cylinder 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 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 |
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.

FAQ:
Q: How to place an order?
A: Please send your inquiry to us directly; we will provide you with the best quote (factory wholesale price) based on your requirements.
Q: How to shipping?
A: If you have a freight forwarder in China, we will delivery to them directly; and we also offer a variety of shipping options for you to choose from. We partner with multiple international logistics providers, including FedEx, DHL, UPS, and EMS etc.
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Note:
This part is designed to meet the manufacturer’s standard specifications for the model. Please verify your equipment’s serial number or the seal kit part number to ensure a correct fit. If you are unsure or cannot locate the appropriate part number, please contact us directly; our professional team will assist you.





