| Parameter | Specification |
|---|---|
| COGENG Part Number | 707-99-66210 |
| OEM Equivalent | Komatsu 707-99-66210 |
| Product Type | Hydraulic Cylinder Seal Kit |
| Kit Type | Complete rebuild set / overhaul kit |
| Application | Multiple Komatsu hydraulic cylinder applications |
| Brand | Part Number |
|---|---|
| COGENG | 707-99-66210 |
| Komatsu | 707-99-66210 |
| Interchange | 707-99-66211, 707-99-66212 |
This seal kit is part of the Komatsu 707-99-XXXX series of hydraulic seal kits, which are widely used across excavator and dozer hydraulic cylinder applications
| Component | Material Grade | Hardness | Temperature Range |
|---|---|---|---|
| Piston Seals | Polyurethane (PU) | 90-92 Shore A | -35°C to +110°C |
| Rod Seals | NBR + PTFE coating | 85 Shore A | -40°C to +120°C |
| Wiper Seals | Polyurethane (PU) | 88-90 Shore A | -35°C to +100°C |
| O-Rings | HNBR (Zetpol) | 70 Shore A | -40°C to +150°C |
| Wear Rings | PTFE + Bronze filler | — | -50°C to +200°C |
| Backup Rings | Nylon 66 (Glass filled) | — | -40°C to +120°C |
| Buffer Seals | Polyurethane | 90 Shore A | -35°C to +110°C |
| Parameter | Rating |
|---|---|
| Maximum Pressure | Up to 350 bar (5,075 psi) |
| Operating Temperature | -40°C to +120°C |
| Fluid Compatibility | Mineral oil, synthetic hydraulic fluids, biodegradable oils |
| Seal Speed Rating | Up to 0.5 m/s |
| Service Life | 5,000+ operating hours |
| Material | Key Benefit |
|---|---|
| Polyurethane (PU) | High abrasion resistance, excellent extrusion resistance |
| NBR/PTFE Rod Seals | Low friction, leak-free operation |
| HNBR O-Rings | Superior heat and chemical resistance |
| PTFE Wear Rings | Prevents metal-to-metal contact, extends cylinder life |
| Nylon Backup Rings | Prevents seal extrusion under high pressure |
| Item | Description | Quantity | Material |
|---|---|---|---|
| 1 | Piston Seal (Primary) | 2 | Polyurethane |
| 2 | Rod Seal (Step-cut) | 2 | NBR + PTFE |
| 3 | Wiper Seal (Double-lipped) | 2 | Polyurethane |
| 4 | Buffer Seal | 2 | Polyurethane |
| 5 | Wear Ring (Piston) | 2 | PTFE Composite |
| 6 | Wear Ring (Gland) | 2 | PTFE Composite |
| 7 | O-Ring (Gland to barrel) | 2 | HNBR |
| 8 | O-Ring (Piston to rod) | 2 | HNBR |
| 9 | O-Ring (End cap) | 4 | HNBR |
| 10 | Backup Ring (Various sizes) | 4 | Nylon 66 |
| 11 | Dust Seal (Rod wiper) | 2 | Polyurethane |
High-strength composite wear rings and dust wipers are included as part of the comprehensive rebuild set
Compatible Equipment Series
| Equipment Type | Compatible Series | Common Cylinder Applications |
|---|---|---|
| Excavators | PC60, PC120, PC200, PC300, PC400, PC450, PC800 | Boom, arm, bucket cylinders |
| Bulldozers/Dozers | D Series | Blade cylinders, ripper cylinders, tilt cylinders |
| Wheel Loaders | WA Series | Steering, bucket, lift cylinders |
| NO | Number | Name | Qty |
| KIT | 707-99-66210 | SERVICE KIT | 2 |
| 707-01-16181 | CYLINDER ASS'Y,STEERING¤ L.H. | 1 | |
| 707-01-16191 | CYLINDER ASS'Y,STEERING¤ R.H. | 1 | |
| 1 | 707-13-16111 | • CYLINDER,L.H. | 1 |
| 707-13-16211 | • CYLINDER,R.H. | 1 | |
| 2 | 707-46-11010 | • BUSHING | 1 |
| 3 | 04071-00170 | • RING,SNAP | 2 |
| 4 | 707-27-16071 | • HEAD,CYLINDER | 1 |
| 5 | 707-52-11010 | • BUSHING | 1 |
| 6 | 707-51-10640 | • RING,BUFFER (KIT) | 1 |
| 7 | 707-51-10130 | • PACKING,ROD (KIT) | 1 |
| 8 | 176-63-56170 | • SEAL,DUST (KIT) | 1 |
| 707-56-10580 | • SEAL,DUST | 1 | |
| 9 | 707-75-10010 | • RING,SNAP | 1 |
| 10 | 07000-15150 | • O-RING (KIT) | 1 |
| 11 | 07146-05152 | • RING,BACK-UP (KIT) | 1 |
| 12 | 01010-82065 | • BOLT | 12 |
| 13 | 01602-22060 | • WASHER,SPRING | 12 |
| 14 | 707-58-10110 | • ROD,PISTON | 1 |
| 15 | 707-76-11310 | • BUSHING | 1 |
| 16 | 07000-12080 | • O-RING (KIT) | 1 |
| 17 | 07001-02080 | • RING,BACK-UP (KIT) | 2 |
| 18 | 707-36-16210 | • PISTON | 1 |
| 19 | 707-44-16180 | • RING,PISTON (KIT) | 1 |
| 707-44-16080 | • RING,PISTON | 1 | |
| 20 | 07155-01640 | • RING,WEAR (KIT) | 2 |
| 21 | 707-40-20030 | • SPACER | 2 |
| 22 | 01010-31245 | • BOLT | 6 |
System Safety: Completely depressurize the hydraulic system and secure the equipment before disassembly. Support the cylinder rod properly during removal.
Cleanliness Protocol: Work in a meticulously clean environment. Use a dedicated clean bench and tools. Even microscopic contaminants can compromise seal life.
Component Assessment: Measure and inspect the cylinder tube ID, piston rod OD, and gland bore for scoring, corrosion, or dimensional wear. Replace components that exceed manufacturer's wear tolerances.
Seat Preparation: Remove all burrs and sharp edges from groove corners with a fine honing stone. Clean all grooves thoroughly with a non-linting cloth.
Seal Installation Technique: Lubricate all seals with the system's clean hydraulic fluid. Use installation sleeves or cones, especially for rod seals. Never use sharp tools to position seals.
Break-in Procedure: After assembly, cycle the cylinder slowly at reduced pressure to seat the seals properly. Monitor for leaks and smooth operation before returning to full service.
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