| Parameter | Value / Specification |
|---|---|
| Temperature Range | -40°F to 225°F (-40°C to 107°C) |
| Fluid Compatibility | Mineral-based hydraulic oils, engine oil, Komatsu-approved fluids, diesel fuel |
| Primary Seal Material | Nitrile Rubber (NBR), FKM (Viton®*), Cork/Rubber Composite, PTFE |
| Seal Hardness (Typical) | 70 Shore A (NBR O-rings), 75-85 Shore A (Gaskets) |
| Pressure Rating | Suitable for static sealing applications up to system operating pressure (e.g., 3,000+ PSI for O-rings in ports) |
| Design Standard | Components manufactured to meet Komatsu's original dimensional and material specifications. |
| Komatsu Equipment Model | Kit Application |
|---|---|
| Komatsu D21A-8 | General Service Seal Kit for Hydraulic System |
| Note: | This kit is a direct replacement for Komatsu OEM part number 707-98-22290. It is a miscellaneous service kit containing seals for various points on the D21A-8 (e.g., hydraulic valve covers, pump connections, pipe fittings, inspection covers). It is NOT a complete cylinder rebuild kit for a single component. |
| Component Type | Material | Color | Typical Size/Shape | Common Application |
|---|---|---|---|---|
| O-Rings (Assorted Sizes) | Nitrile (NBR) | Black | AS568 Dash # series (e.g., -010, -112, -214) | Hydraulic fittings, pipe connections, valve spools |
| O-Rings (Specific Fuel/Oil) | FKM (Viton®*) | Brown | Metric diameters | Fuel line connections, high-temp oil ports |
| Gaskets (Cylinder Head Cover) | Cork/Rubber Composite | Black/Black | Rectangular, with bolt holes | Valve cover gaskets |
| Gaskets (Flat Seals) | Compressed Fiber | Grey | Various shapes & thicknesses | Inspection covers, flange faces |
| Backup Washers | Nylon / PTFE | White / Tan | Flat washer shape | For use with O-rings in high-pressure ports |
| Seal Rings (D-rings, Square-rings) | NBR / Polyurethane | Black / Brown | D-shaped or square cross-section | Piston seals for control valves, pump parts |
| Lip Seals | NBR with Steel Case | Black/Grey | Small diameter shaft seals | For rotating shafts (e.g., lever shafts) |
| Application Sector | Target Equipment | Common Uses for This Kit |
|---|---|---|
| Compact Equipment Maintenance | Komatsu D21A-8 Compact Dozer | Repairing leaks at hydraulic hose fittings, valve cover gaskets, pipe flange connections, inspection plates, and fuel line joints. |
| Preventative Maintenance | General Hydraulic System Servicing | Performing system component inspections, replacing worn seals during pump/valve service, and keeping a stock of common seals for field repairs. |
| Equipment Repair Shops | Multi-Application Seal Inventory | A cost-effective way to have the correct OEM-specified seals on hand for a wide range of common leak points on the D21A-8 model. |
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)
