- CN
| Parameter | Value / Specification |
|---|---|
| Maximum Operating Pressure | Up to 3,625 PSI (250 bar) |
| Temperature Range | -40°F to 225°F (-40°C to 107°C) |
| Fluid Compatibility | Mineral-based hydraulic oils, Komatsu-approved fluids (e.g., KSHV), standard AW/HLP fluids |
| Primary Seal Material | Polyurethane (AU) & Nitrile Rubber (NBR) |
| Seal Hardness (Dynamic) | 88-92 Shore A (Polyurethane) |
| Seal Hardness (Static) | 70 Shore A (NBR O-Rings) |
| Design Standard | Manufactured to meet or exceed Komatsu's original specifications for fit, function, and service life. |
| Komatsu Machine Model | Specific Application Note |
|---|---|
| Komatsu WB140-2 | Refer to Service Manual for Specific Cylinder Application |
| Komatsu WB150-2 | Refer to Service Manual for Specific Cylinder Application |
| Note: | This kit is a direct replacement for Komatsu OEM part number 878000541. The exact cylinder application (e.g., Boom, Bucket, Stabilizer) varies. It is critical to verify the specific component this kit is intended for using the machine's official Komatsu service manual or parts catalog based on this part number. |
| Component Name | Material | Color | Durometer | Function |
|---|---|---|---|---|
| Main Piston Seal (U-Cup) | Polyurethane (AU) | Brown | 90 Shore A | Primary dynamic pressure seal on piston |
| Rod Seal (Step Seal) | Cast Polyurethane (CU) | Black | 90 Shore A | Main rod seal for pressure retention |
| Wiper/Scraper | Polyurethane (PU) | Black | 85 Shore A | Excludes contaminants from rod |
| Buffer Ring | Polyurethane (CU) | Black | 88 Shore A | Protects rod seal from pressure spikes |
| O-Ring Set (Assorted) | Nitrile Rubber (NBR) | Black | 70 Shore A | Static sealing for gland, ports, fittings |
| Wear Ring / Guide Band | Filled PTFE / Nylon | Brown / White | N/A | Guides piston/rod, prevents metal contact |
| Backup Rings | Nylon | Tan | N/A | Prevents O-ring extrusion under high pressure |
Safe Depressurization & Support: Park the machine on level ground. Lower all attachments (bucket, stabilizers, backhoe) to the ground to relieve hydraulic pressure.
Clean Workspace: Perform all work in a meticulously clean environment to prevent contamination of the hydraulic system.
Documented Disassembly: Carefully disassemble the cylinder. Photograph and label each component and its orientation.
Mandatory Metal Inspection: Thoroughly inspect the cylinder rod for scratches, pitting, or scoring. Inspect the cylinder bore for wear or damage. Replace any damaged metal components before installing new seals.
Proper Seal Installation: Lubricate all new seals with clean hydraulic fluid. Use seal installation tools (cone tools, sleeves) to guide seals over threads and sharp edges without damage.
Precision Reassembly: Follow the included diagram for correct seal order and orientation. Ensure all seals are fully seated in their grooves.
Torque Specifications: Use a calibrated torque wrench. Adhere strictly to Komatsu's specified torque values and sequences for all fasteners (gland bolts, tie-rods)
