| Parameter | Value / Specification |
|---|---|
| Maximum System Pressure | Up to 5,220 PSI (360 bar) |
| Temperature Range | -40°F to 225°F (-40°C to 107°C) |
| Fluid Compatibility | Mineral-based oils, Komatsu Super Hydraulic Fluid (KSHV), synthetic HFDU fluids |
| Primary Seal Material | Polyurethane (AU), Cast Polyurethane (CU), Nitrile Rubber (NBR) |
| Seal Hardness (Dynamic) | 92-95 Shore A (Polyurethane Main Seals) |
| Seal Hardness (Static) | 70 Shore A (NBR O-Rings) |
| Design Standard | Manufactured to meet or exceed Komatsu DHTA (Dantotsu High-Tech Advance) specifications for high-pressure, high-cycle applications. |
| Komatsu Machine Model | Specific Cylinder Application |
|---|---|
| Komatsu PC300LC-8 | Arm (Stick) Cylinder |
| Komatsu PC350LC-8 | Arm (Stick) Cylinder |
| Note: | This kit is a direct replacement for Komatsu OEM part number 707-52-90220. It is designed specifically for the ARM (STICK) CYLINDER on the listed 30-35 ton class excavator models. Always verify your machine's model, serial number, and that you are servicing the ARM CYLINDER (not the boom or bucket cylinder) before installation. |
| Component Name | Material | Color | Durometer | Function |
|---|---|---|---|---|
| Main Piston Seal (U-Cup) | Polyurethane (AU) | Brown | 95 Shore A | Primary high-pressure dynamic seal on piston |
| Rod Seal (Step Seal) | Cast Polyurethane (CU) | Black | 93 Shore A | Main rod seal for pressure retention & low friction |
| Wiper/Scraper (Heavy-Duty) | Polyurethane (PU) | Black | 90 Shore A | Primary contaminant exclusion for harsh environments |
| Buffer Ring | Polyurethane (CU) | Black | 90 Shore A | Protects rod seal from pressure spikes and pulsation |
| O-Ring Set (Assorted) | Nitrile Rubber (NBR) | Black | 70 Shore A | Static sealing for gland assembly, ports, and plugs |
| Wear Ring / Guide Band | Glass-Filled PTFE | Dark Brown | N/A | Piston guidance, absorbs side loads, prevents metal contact |
| Backup Rings | Nylon 6.6 | Tan | N/A | Prevents extrusion of static O-rings under extreme pressure |
| NO | Number | Name | Qty |
| 707-99-24670 | SERVICE KIT | 1 | |
| 707-00-0A042 | CYLINDER ASS'Y | 1 | |
| 1 | 721-11-90360 | • CYLINDER | 1 |
| 2 | 02896-11008 | • O-RING (KIT) | 2 |
| 3 | 707-46-03020 | • BUSHING | 1 |
| 4 | 04065-07225 | • RING,SNAP | 2 |
| 5 | 07020-00675 | • FITTING,GREASE | 1 |
| 6 | 707-29-90601 | • HEAD,CYLINDER | 1 |
| 7 | 707-52-90220 | • BUSHING | 1 |
| 8 | 707-51-45030 | • PACKING,ROD (KIT) | 1 |
| 9 | 707-51-45640 | • RING,BUFFER (KIT) | 1 |
| 10 | 707-56-45580 | • SEAL,DUST (KIT) | 1 |
| 11 | 07179-12057 | • RING,SNAP | 1 |
| 12 | 07000-12085 | • O-RING (KIT) | 1 |
| 13 | 07146-02086 | • RING,BACK-UP (KIT) | 1 |
| 14 | 07000-12090 | • O-RING (KIT) | 1 |
| 15 | 707-58-45900 | • ROD,PISTON | 1 |
| 16 | 707-46-03020 | • BUSHING | 1 |
| 17 | 04065-07225 | • RING,SNAP | 2 |
| 18 | 07020-00900 | • FITTING,GREASE | 1 |
| 19 | 707-36-90360 | • PISTON | 1 |
| 20 | 707-44-90180 | • RING,PISTON (KIT) | 1 |
| 21 | 07156-00912 | • RING,WEAR (KIT) | 1 |
| 22 | 707-67-33010 | • NUT | 1 |
Safe Depressurization & Support: Park the excavator on level ground. Lower the bucket fully to the ground to relieve all hydraulic pressure. Mechanically block the bucket or cylinder rod to prevent any movement.
Ultra-Clean Environment: Perform all work in a meticulously clean, dust-controlled area. Bucket cylinders are highly susceptible to abrasive contamination. Use a parts washer, clean solvent, and lint-free cloths.
Documented Disassembly: Carefully disassemble the cylinder gland. Photograph and label each component and its precise orientation. Note the exact stacking order of all seals and spacers in the gland.
Mandatory Metal Inspection: Use a micrometer to inspect the cylinder rod for scratches, pitting, or scoring. Inspect the cylinder bore (ID) for wear, tapering, or scoring. Damaged metal components must be replaced.
Proper Seal Installation: Soak all new elastomeric seals in clean hydraulic fluid. Use seal installation cones, sleeves, and nylon picks designed for large diameters. Never use sharp metal tools that can nick seals.
Precision Reassembly: Follow the included diagram exactly for seal order and orientation. Ensure each seal is fully and squarely seated in its groove before proceeding to the next.
Torque Specifications: Use a calibrated torque wrench. Adhere strictly to Komatsu's specified torque values and sequences for gland bolts or tie-rods. Use a criss-cross pattern for even flange compression.
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