- CN
| Parameter | Value / Specification |
|---|---|
| Maximum Operating Pressure | Up to 4,060 PSI (280 bar) |
| Temperature Range | -40°F to 225°F (-40°C to 107°C) |
| Fluid Compatibility | Mineral-based hydraulic oils, Komatsu Super Hydraulic Fluid (KSHV), BIO HFDU fluids |
| Primary Seal Material | Polyurethane (AU) & Nitrile Rubber (NBR) |
| Seal Hardness (Dynamic) | 92-94 Shore A (Polyurethane) |
| Seal Hardness (Static) | 70 Shore A (NBR O-Rings) |
| Design Standard | Manufactured to meet or exceed Komatsu's original specifications for pressure holding, wear resistance, and service life in dozer applications. |
| Komatsu Equipment Model | Specific Application |
|---|---|
| Komatsu D39EX-21 | Blade Angle (Tilt) Cylinders (Left and Right) |
| Komatsu D39PX-21 | Blade Angle (Tilt) Cylinders (Left and Right) |
| Note: | This kit is a direct replacement for Komatsu OEM part number 707-98-24910. It is designed specifically for the ANGLE/TILT CYLINDERS on the listed D39-21 series dozers. Verify your machine model, serial number, and that you are servicing the ANGLE CYLINDERS, not the lift or pitch cylinders. |
| Component Name | Material | Color | Durometer | Function |
|---|---|---|---|---|
| Main Piston Seal (U-Cup) | Polyurethane (AU) | Brown | 94 Shore A | Primary dynamic pressure seal on piston |
| Rod Seal (Step Seal) | Cast Polyurethane (CU) | Black | 93 Shore A | Main rod seal for pressure retention |
| Wiper/Scraper (Heavy-Duty) | Polyurethane (PU) | Black | 90 Shore A | Excludes abrasive dirt, mud, and debris |
| Buffer Ring | Polyurethane (CU) | Black | 90 Shore A | Dampens pressure spikes to protect rod seal |
| O-Ring Kit (Assorted) | Nitrile Rubber (NBR) | Black | 70 Shore A | Static sealing for gland, end cap, and ports |
| Wear Ring / Guide Band | Glass-Filled PTFE | Dark Brown | N/A | Centralizes piston, prevents metal contact |
| Backup Rings | Nylon 6.6 | Tan | N/A | Prevents extrusion of static O-rings under pressure |
| 707-00-0A300 | CYLINDER ASS'Y | 2 | |
| 1 | 707-11-85080 | • CYLINDER | 1 |
| 2 | 707-46-03020 | • BUSHING | 1 |
| 3 | 04065-07225 | • RING,SNAP | 2 |
| 4 | 07020-00900 | • FITTING,GREASE | 1 |
| 5 | 707-29-85830 | • HEAD,CYLINDER | 1 |
| 6 | 07177-04530 | • BUSHING | 1 |
| 7 | 707-51-45210 | • PACKING,ROD (KIT) | 1 |
| 8 | 112-63-15370 | • SEAL,DUST (KIT) | 1 |
| 9 | 07179-12057 | • RING,SNAP | 1 |
| 10 | 07000-12080 | • O-RING (KIT) | 1 |
| 11 | 707-35-52770 | • RING,BACK-UP (KIT) | 1 |
| 12 | 07000-12085 | • O-RING (KIT) | 1 |
| 13 | 721-58-45260 | • ROD,PISTON | 1 |
| 14 | 707-46-03020 | • BUSHING | 1 |
| 15 | 04065-07225 | • RING,SNAP | 2 |
| 16 | 07020-00900 | • FITTING,GREASE | 1 |
| 17 | 707-36-85170 | • PISTON | 1 |
| 18 | 707-44-85180 | • RING,PISTON (KIT) | 1 |
| 19 | 707-39-85120 | • RING,WEAR (KIT) | 1 |
| 20 | 707-67-33010 | • NUT | 1 |
| 707-98-24910 | 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.
