| Parameter | Value / Specification |
|---|---|
| Cylinder Bore (Inner Ø) | 110 mm |
| Piston Rod Diameter (Ø) | 75 mm |
| Maximum Operating Pressure | Up to 4,350 PSI (300 bar) |
| Temperature Range | -40°F to 225°F (-40°C to 107°C) |
| Fluid Compatibility | Mineral-based hydraulic oils, Komatsu Super Hydraulic Fluid (KSHV), synthetic HFDU fluids |
| Primary Seal Material | Polyurethane (AU), Cast Polyurethane (CU), Nitrile Rubber (NBR) |
| Seal Hardness (Dynamic) | 90-94 Shore A (Polyurethane) |
| Seal Hardness (Static) | 70 Shore A (NBR O-Rings) |
| Weight | Approx. 430 g |
| Design Standard | Manufactured to meet or exceed Komatsu's original specifications |
| Komatsu Excavator Model | OEM Part Number | Cylinder Application |
|---|---|---|
| Komatsu PC160LC-7 | 707-99-38720 | Boom Cylinder |
| Komatsu PC160LC-7K | 707-99-38720 | Boom Cylinder |
| Komatsu PC160LC-7K-KA | 707-99-38720 | Boom Cylinder |
| Komatsu PC180LC-7K | 707-99-38720 | Boom Cylinder |
| Komatsu PC180NLC-7K | 707-99-38720 | Boom Cylinder |
| Note: | This kit is designed for cylinders with 110mm bore and 75mm rod diameter. Verify your machine's model and serial number before installation. |
| Component Name | Material | Color | Durometer | Function |
|---|---|---|---|---|
| Main Piston Seal (U-Cup) | Polyurethane (AU) | Brown | 94 Shore A | Primary dynamic pressure seal on piston |
| Rod Seal (Step Seal) | Cast Polyurethane (CU) | Black | 93 Shore A | Main rod seal for pressure retention |
| Wiper/Scraper (Heavy-Duty) | Polyurethane (PU) | Black | 90 Shore A | Excludes dirt, dust, and debris from rod |
| Buffer Ring | Polyurethane (CU) | Black | 90 Shore A | Absorbs pressure spikes to protect rod seal |
| O-Ring Kit (Assorted) | Nitrile Rubber (NBR) | Black | 70 Shore A | Static sealing for gland, end cap, and ports |
| Wear Ring / Guide Band | Glass-Filled PTFE | Dark Brown | N/A | Centralizes piston, prevents metal contact |
| Backup Rings | Nylon 6.6 | Tan | N/A | Prevents extrusion of static O-rings under pressure |
| Dust Seal | Polyurethane | Black | 85 Shore A | Secondary contaminant exclusion |
Main Piston Seal (U-Cup) – Qty: 1
Rod Seal (Step Seal) – Qty: 1
Wiper/Scraper (Heavy-Duty) – Qty: 1
Buffer Ring – Qty: 1
Wear Ring (Piston) – Qty: 1
Dust Seal – Qty: As required
Complete O-Ring & Backup Ring Set – Qty: 1 Set (All necessary sizes for gland, port, and fitting assembly)
Note: This kit is designed specifically for 110mm bore x 75mm rod boom cylinders An exploded diagram is included for correct assembly.
Support Seals & Hardware
Full set of precision-molded static O-rings for all gland and port connections
Essential wear guide band to ensure smooth piston travel and minimize side load on seals
High-pressure nylon backup rings for critical O-ring applications
Excluded Items: This is a seal and wear component kit only. It does NOT include the piston, cylinder rod, barrel, gland nut, bearings, bolts, or any other metal parts or hardware.
Installation decomposition diagram
Frequently Asked Questions
Q1: Which Komatsu excavator models use the 707-99-38720 boom cylinder seal kit?
A: This seal kit is designed for specific Komatsu excavator boom cylinders that require OEM part number 707-99-38720. Please check your machine model and cylinder part number before ordering.
Q2: Is this an OEM or aftermarket seal kit?
A: It is an OEM-grade heavy-duty replacement kit, manufactured to meet or exceed original Komatsu specifications for sealing performance, durability, and fit.
Q3: What makes this a "heavy-duty" boom cylinder seal kit?
A: The kit features premium polyurethane seals and high-grade rubber compounds designed to withstand extreme hydraulic pressures, temperature fluctuations, and heavy digging applications.
Q4: What is included in the COGENG 707-99-38720 seal kit?
A: The kit includes all necessary rod seals, piston seals, wipers, O-rings, and backup rings for a complete boom cylinder rebuild – no missing parts.
Q5: How do I purchase the COGENG 707-99-38720 boom cylinder seal kit?
A: Contact us with your Komatsu machine model and cylinder details for fitment confirmation, then order directly through our website or sales team for fast shipping.
Contact COGENG
📞 Phone: +86-185-2913-1515 🌐 Instagram
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🌐 Website: cogeng.net
