- CN
| Parameter | Value / Specification |
|---|---|
| Temperature Range | -40°F to 300°F (-40°C to 149°C) [Varies by component] |
| Fluid Compatibility | Hydraulic Oil (Mineral & Synthetic), Engine Oil, Diesel Fuel, Coolant, Grease |
| Primary Seal Materials | Nitrile Rubber (NBR), Fluoroelastomer (FKM/Viton®*), PTFE, Compressed Fiber, Cork/Rubber |
| Seal Hardness (Typical) | 70-90 Shore A (Elastomers) |
| Pressure Rating | Suitable for static and low-dynamic applications up to full system pressure (e.g., 5,000+ PSI for port O-rings) |
| Design Standard | All components manufactured to meet Komatsu's original dimensional, material, and performance specifications. |
| Komatsu Equipment Model | Kit Application & Note |
|---|---|
| Komatsu D39EX-21 | General Service Seal Kit (SN Specific) |
| Komatsu D39PX-21 | General Service Seal Kit (SN Specific) |
| Note: | This kit is a direct replacement for Komatsu OEM part number 707-98-24700. It is a miscellaneous service kit containing a vast assortment of seals for various locations on the D39-21 series. Its contents are often tailored to a specific Serial Number (SN) range. It is NOT a cylinder-specific rebuild kit. |
| Component Type | Material | Color | Common Application Examples |
|---|---|---|---|
| O-Rings (Hydraulic) | Nitrile (NBR) | Black | Hydraulic hose fittings, pipe threads, valve block ports, pump flanges |
| O-Rings (Fuel/Oil/High-Temp) | Fluoroelastomer (FKM) | Brown | Fuel line connections, high-temperature oil galleries, turbocharger lines |
| Flat Gaskets | Compressed Fiber / Graphite | Grey/Black | Inspection covers, manifold covers, hydraulic tank covers, filter housings |
| Formed Gaskets | Cork/Rubber Composite | Black | Valve covers, oil pan, transmission covers |
| Lip Seals & Rotary Shaft Seals | NBR with Steel Case | Black/Grey | PTO shafts, lever pivot points, pump drive shafts |
| Backup Rings/Washers | Nylon / PTFE | White/Tan | For high-pressure hydraulic O-ring applications |
| D-Rings & Square Rings | Polyurethane / NBR | Black/Brown | Piston seals in control valves, accumulator pistons |
| Thread Sealant Tape | PTFE | White | For NPT threaded pipe fittings |
| NO | Number | Name | Qty |
| G-1 | 707-00-XA280 | CYLINDER GROUP,L.H. | 1 |
| G-2 | 707-00-XA290 | CYLINDER GROUP,R.H. | 1 |
| ==================== | |||
| 707-00-0A280 | CYLINDER ASS'Y,L.H. | 1 | |
| 707-00-0A290 | CYLINDER ASS'Y,R.H. | 1 | |
| 1 | 707-11-90910 | • CYLINDER,L.H. | 1 |
| 1 | 707-11-90920 | • CYLINDER,R.H. | 1 |
| 2 | 07143-10505 | • BUSHING | 1 |
| 3 | 07145-00050 | • SEAL,DUST (KIT) | 2 |
| 4 | 707-29-90820 | • HEAD,CYLINDER | 1 |
| 5 | 07177-04530 | • BUSHING | 1 |
| 6 | 707-51-45210 | • PACKING,ROD (KIT) | 1 |
| 7 | 112-63-15370 | • SEAL,DUST (KIT) | 1 |
| 8 | 07179-12057 | • RING,SNAP | 1 |
| 9 | 07000-12085 | • O-RING (KIT) | 1 |
| 10 | 07146-02086 | • RING,BACK-UP (KIT) | 1 |
| 11 | 07000-12090 | • O-RING (KIT) | 1 |
| 12 | 721-58-45250 | • ROD,PISTON | 1 |
| 13 | 07143-10505 | • BUSHING | 1 |
| 14 | 07145-00050 | • SEAL,DUST (KIT) | 2 |
| 15 | 707-36-90360 | • PISTON | 1 |
| 16 | 07156-00912 | • RING,WEAR (KIT) | 1 |
| 17 | 707-44-90180 | • RING,PISTON (KIT) | 1 |
| 18 | 707-67-33010 | • NUT | 1 |
| 19 | 02896-11012 | • O-RING (KIT) | 2 |
| 20 | 707-86-46610 | TUBE,L.H. | 1 |
| 20 | 707-86-46620 | TUBE,R.H. | 1 |
| 21 | 02896-11012 | O-RING (KIT) | 1 |
| 22 | 01010-81016 | BOLT | 1 |
| 23 | 01643-31032 | WASHER | 1 |
| ==================== | |||
| 707-98-24700 | SERVICE KIT | 2 |
Full set of precision-molded static O-rings for all gland and port sealing points.
Essential wear guide band to ensure smooth piston travel and minimize side load.
Necessary high-pressure nylon backup rings.
Excluded Items: This is a seal and wear component kit only. It does NOT include the piston, cylinder rod, barrel, gland nut, bearings, bolts, pins, or any other metal parts or hardware.
Machine Secure & Pressure Relief: Park the dozer on firm, level ground. Lower the blade fully to relieve all hydraulic pressure. Engage parking brake and block tracks.
Cleanliness Protocol: Perform disassembly and assembly in an impeccably clean, dust-controlled environment. Abrasive contamination is the leading cause of seal failure.
Documented Disassembly: Carefully disassemble the cylinder. Photograph and note the exact order and orientation of all components, especially the seal stack in the gland.
Critical Metal Inspection: Inspect the cylinder rod for scratches, gouges, or corrosion. Check the cylinder bore (ID) for scoring, pitting, or excessive wear. Damaged metal components MUST be replaced.
Lubricated Assembly: Soak all new elastomeric seals in clean hydraulic fluid. Lightly lubricate all seal grooves and sliding surfaces before installation.
Proper Tool Use: Use seal installation tools (cone tools, picks, sleeves) to carefully install seals without cutting, stretching, or rolling them over sharp edges.
Torque to Specification: During reassembly, use a calibrated torque wrench. Adhere strictly to Komatsu's specified torque values and sequences for all fasteners.
