| Parameter | Specification |
|---|---|
| Part Number | 707-98-24910 |
| Product Name | Komatsu Angle Cylinder Seal Kit |
| Supplier / Channel | COGENG (Factory Direct Supply) – Genuine Komatsu OEM-Spec Seals |
| Cylinder Application | Angle Cylinder (Controls blade side-to-side angling, typically PAT blade configuration) |
| Compatible Models | Komatsu D39EX-21, D39PX-21 (Crawler Dozers with Power Angle Tilt blade) |
| Rod Diameter | 65 mm |
| Bore Diameter | 115 mm |
| Kit Contents | Dust Seal (Wiper), Rod U-Packing (Main Seal), Buffer Ring, Piston Seal, O-Rings, Backup Rings, Wear Rings |
| Material Specification | OEM-Spec Polyurethane (H-ECOPUR), Nitrile Butadiene Rubber (NBR), Glass-Filled Nylon (Wear Rings) |
| Supply Type | Factory Direct – Full Kit with all required components for one Angle Cylinder overhaul |
Technical Constants & Performance Data
| 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 Specifications Table
| 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 |
Parts list
|
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 |
Decompose pictures
Installation decomposition diagram
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.
|
OEM Part Number |
707-98-24910 / 7079824910 |
|
Brand |
COGENG (Premium OEM Replacement) |
|
Kit Type |
Angle Cylinder Seal Kit |
|
Compatible Models |
Komatsu D39EX-21, D39PX-21 Dozers |
|
Cylinder Application |
Blade Tilt Cylinder / Angle Cylinder |
|
Key Feature |
Premium seals for precise blade angle control and leak prevention |
Frequently Asked Questions
Q1: My D39-21 has a straight tilt blade (not PAT / Power Angle Tilt). Do I need 707-98-24910?
A: No. The 707-98-24910 Angle Cylinder Seal Kit is specifically for the Angle Cylinder on machines equipped with the PAT (Power Angle Tilt) blade option. If your dozer has a standard tilt-only blade, there is no angle cylinder, and this kit is not needed. For the standard Lift and Tilt cylinders, order the comprehensive kit 707-98-24700 or individual cylinder kits.
Q2: Can I use this kit on a D37EX-21 or D61EX-23?
A: Not unless confirmed by your machine's Parts Manual. While the rod and bore dimensions (65mm/115mm) are common on other Komatsu medium dozers, the specific seal profiles, groove widths, and dust seal outer diameters can vary even with the same nominal bore/rod size. Always verify your machine's serial number in the Komatsu Parts Book or query COGENG with your full model and serial number before cross-referencing.
Q3: The 707-98-24910 kit I received has a blue piston seal instead of the expected black one. Is it genuine Komatsu quality?
A: Yes. COGENG factory-direct kits are manufactured to OEM-Spec standards. Komatsu and their licensed suppliers frequently color-code seal materials:
Black: Standard NBR (Nitrile) rubber — common in older kits.
Blue / Turquoise: High-performance H-ECOPUR Polyurethane — superior abrasion resistance and longer service life, especially in the angle cylinder application which experiences high side loads and shock impacts.
Green / Yellow: Often indicates fluorocarbon (FKM) or high-temperature compounds for specific extreme applications.
Blue is a factory-approved upgrade, not a defect.
Q4: I'm ordering this kit factory direct from COGENG. Does it include the Wear Rings?
A: Yes. COGENG supplies the 707-98-24910 as a complete kit, which includes the Glass-Filled Nylon Piston Wear Rings (Qty 2) needed for a full angle cylinder overhaul. Unlike some stripped-down aftermarket alternatives, this direct supply kit is comprehensive and ready for a complete cylinder rebuild without ordering additional parts.
Q5: What are the common signs that my D39EX-21 angle cylinder needs this seal kit?
A:
External Oil Leakage: Visible hydraulic oil dripping down the chrome rod or puddling on the blade structure.
Blade Angle Creep/Drift: With the machine running and blade off the ground in neutral angle position, the blade slowly angles to one side on its own.
Slow or Jerky Angle Movement: When operating the angle pedal/lever, the blade responds sluggishly or moves in a chattering fashion.
Contaminated Oil: Evidence of dirt or water entry past a failed dust wiper, indicated by "milky" or dark gritty oil samples from the cylinder circuit.
Any of these symptoms indicate that 707-98-24910 should be ordered and installed promptly to prevent further damage to the cylinder barrel and rod.
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