Technical Constants & Performance Data
|
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. |
| Part Number | 707-98-24700 (7079824700) |
| Product Name | Komatsu Comprehensive Dozer Service Seal Kit |
| Supplier / Channel | COGENG (Aftermarket Parts Distributor) - Genuine Komatsu OEM Part |
| Coverage | Complete Dozer Hydraulic Cylinders — Blade Lift + Blade Tilt / Angle |
| Compatible Models | Komatsu D39EX-21, D39PX-21 (Crawler Dozers) |
| Cylinders Covered | Lift Cylinder (Left + Right), Tilt Cylinder |
| Typical Rod Diameters | Lift: 65 mm Tilt: 55 mm |
| Typical Bore Diameters | Lift: 115 mm Tilt: 110 mm |
| Kit Contents (Summary) | Dust Seals, Rod U-Packings, Buffer Rings, Piston Seals, O-Rings, Backup Rings, Wear Rings — for all covered cylinders |
|
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 Specifications Table
|
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 |
Parts list
|
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 |
|
OEM Part Number |
707-98-24700 / 7079824700 |
|
Brand |
COGENG (Premium OEM Replacement) |
|
Kit Type |
Comprehensive Dozer Service Seal Kit |
|
Compatible Models |
Komatsu D39EX-21, D39PX-21 Dozers |
|
Service Coverage |
Complete Hydraulic Cylinder & System Restoration |
|
Key Feature |
All-in-one comprehensive kit for D39-21 series major service |
Decompose pictures
Installation decomposition diagram
WARNING: Comprehensive Dozer Cylinder Overhaul Hazards
Multi-Cylinder Support: This kit 707-98-24700 supports servicing all front attachment cylinders (Lift and Tilt). Each cylinder is a heavy assembly. When removing multiple cylinders simultaneously, the dozer blade and frame must be supported on heavy-duty cribbing (timber blocks rated for 10+ tons) in at least four points. NEVER rely solely on the machine's control valves to hold the blade in position.
Hydraulic Energy Isolation:
Engine OFF, key removed.
Hydraulic lockout lever in the LOCKED position.
Cycle all blade control levers (raise/lower/tilt/angle) at least 5 times in all directions to release residual pressure in the accumulator and pilot lines.
Carefully crack the hydraulic tank breather cap to release any tank pressure buildup.
Pin Release Hazard: D39 lift/tilt cylinder pins are secured with lock bolts or snap rings. When extracting the pin, the blade linkage may shift. Stand clear of the linkage arc. Use a hydraulic pin press (not a sledgehammer) to remove seized pins. Hammering creates flying metal splinters and can damage the cylinder rod eye.
Personal Protective Equipment (PPE): Full face shield, steel-toe boots, heavy leather gloves, and flame-resistant clothing are mandatory when working with high-pressure hydraulic systems and heavy linkage components.
Q1: How is this Comprehensive Kit (707-98-24700) different from a single cylinder seal kit for the D39?
A: The 707-98-24700 is a "Master/Bucket Kit" that includes seals for ALL front attachment cylinders: both Left and Right Lift Cylinders (65mm rod) plus the Tilt Cylinder (55mm rod). It is designed for a complete dozer hydraulic system overhaul, saving cost and downtime compared to ordering three individual cylinder kits separately.
Q2: Does this kit cover the Angle cylinder if my D39PX-21 has a Power Angle Tilt (PAT) blade?
A: Check specific configuration. The D39PX-21 standard configuration uses a standard Tilt cylinder. If equipped with a PAT (Power Angle Tilt) blade, the Angle cylinder is a separate component with its own seal dimensions. Verify your equipment configuration before disassembly. The 707-98-24700 covers standard Lift and Tilt cylinders as documented in the D39-21 Shop Manual.
Q3: My D39EX-21 blade creeps down slowly under its own weight. Will this kit fix that?
A: Yes, most likely. Slow blade creep (no external leaking) is typically caused by worn Piston Seals (#4 for lift, #11 for tilt) in the lift cylinders. Because the creep is usually bilateral, both lift cylinders should be resealed simultaneously. This kit provides seals for both. You must also inspect the cylinder barrel bore — if it's scored from a failed wear ring, a new seal kit will not stop the creep for long.
Q4: Does COGENG's 707-98-24700 include the Piston Wear Rings? Some third-party "seal kits" leave them out.
A: When supplied as Genuine Komatsu through COGENG, Yes. Komatsu OEM "P-U" (Repair Seal Kit) part numbers always include the glass-filled nylon Piston Wear Rings. If you receive the kit and find the wear rings missing, contact COGENG immediately — it may be an incomplete aftermarket substitute. The wear rings are critical: running without them destroys the cylinder barrel.
Q5: Are there special tools required to use this kit properly?
A: Yes. Recommended tools for a correct D39 cylinder rebuild:
Gland Nut Spanner Wrench (adjustable, pin-type) – to unscrew the head gland without damaging threads.
Piston Ring Compressor – to compress the new wear rings and piston seal during reinsertion into the barrel.
Torque Multiplier (3:1 or 4:1) with heavy-duty socket – for proper piston nut torque.
Brass Drift / Plastic Seal Pick – to remove old seals without scratching the steel groove floors. Steel picks will score the gland.
Contact COGENG
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