Technical Constants & Performance Data
| Parameter | Value / Specification |
|---|---|
| Maximum Operating Pressure | Up to 3,625 PSI (250 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) | 90-92 Shore A (Polyurethane) |
| Seal Hardness (Static) | 70 Shore A (NBR O-Rings) |
| Design Standard | Engineered to meet Komatsu's specifications for dozer cylinder performance and service life. |
Exact Model Compatibility
| Komatsu Equipment Model | Specific Application |
|---|---|
| Komatsu D31EX-21 | Blade Angle (Tilt) Cylinders (Left and Right) |
| Komatsu D31PX-21 | Blade Angle (Tilt) Cylinders (Left and Right) |
| Note: | This kit is the exact replacement for Komatsu OEM part number 707-98-22850. It is designed for the specific bore, rod, and gland configuration of the angle cylinders on the D31-21 series dozers. Verify your machine's model, serial number, and that you are servicing the BLADE ANGLE CYLINDERS before purchase. |
Component Specifications Table
| Component Name | Material | Color | Durometer | Function |
|---|---|---|---|---|
| Piston Seal (Main) | Polyurethane (AU) | Brown | 92 Shore A | Primary dynamic pressure seal on piston |
| Rod Seal (Step Seal) | Cast Polyurethane (CU) | Black | 90 Shore A | Main rod seal, retains pressure in cylinder |
| Wiper/Scraper (Heavy-Duty) | Polyurethane (PU) | Black | 88 Shore A | Excludes abrasive dirt, mud, and moisture |
| Buffer Ring | Polyurethane (CU) | Black | 88 Shore A | Protects rod seal from pressure spikes |
| 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 | Brown | N/A | Centralizes piston, prevents metal contact |
| Backup Rings | Nylon 6.6 | White/Tan | N/A | Prevents extrusion of O-rings under pressure |
| Application Sector | Primary Equipment | Symptoms Addressed by This Kit |
|---|---|---|
| Earthmoving & Site Prep | Komatsu D31EX/PX-21 Dozer | Inability to hold blade angle ("drift"), visible hydraulic oil leakage from the rod gland, slow or weak blade tilt response, oil accumulation around cylinder. |
| Construction & Landscaping | Bulldozer Blade Control Cylinders | Loss of precise grading control, increased hydraulic fluid consumption, reduced dozer efficiency and productivity. |
| Heavy Equipment Repair | Scheduled Maintenance & Leak Repair | Restores factory sealing performance for precise blade operation, prevents environmental contamination, and avoids costly cylinder replacement. |
Decompose pictures
Parts list
|
NO |
Number |
Name |
Qty |
|
707-00-0A031 |
CYLINDER ASS'Y |
2 |
|
|
1 |
707-11-75321 |
• CYLINDER |
1 |
|
2 |
114-63-55170 |
• BUSHING |
1 |
|
3 |
04065-06220 |
• RING,SNAP |
2 |
|
4 |
07020-00900 |
• FITTING,GREASE |
1 |
|
5 |
707-29-75831 |
• HEAD,CYLINDER |
1 |
|
6 |
707-52-10410 |
• BUSHING |
1 |
|
7 |
707-51-40210 |
• PACKING,ROD (KIT) |
1 |
|
8 |
198-63-75190 |
• SEAL,DUST (KIT) |
1 |
|
9 |
07179-12052 |
• RING,SNAP |
1 |
|
10 |
07000-12070 |
• O-RING (KIT) |
1 |
|
11 |
707-35-52760 |
• RING,BACK-UP (KIT) |
1 |
|
12 |
07000-12075 |
• O-RING (KIT) |
1 |
|
13 |
721-58-40930 |
• ROD,PISTON |
1 |
|
14 |
114-63-55170 |
• BUSHING |
1 |
|
15 |
04065-06220 |
• RING,SNAP |
2 |
|
16 |
07020-00900 |
• FITTING,GREASE |
1 |
|
17 |
707-36-75370 |
• PISTON |
1 |
|
18 |
707-44-75180 |
• RING,PISTON (KIT) |
1 |
|
19 |
707-39-75190 |
• RING,WEAR (KIT) |
1 |
|
20 |
707-67-30030 |
• NUT |
1 |
|
21 |
02896-11009 |
• O-RING (KIT) |
2 |
|
707-98-22850 |
SERVICE KIT |
2 |
Installation decomposition diagram
Machine Secure & Pressure Relief: Park the dozer on a firm, level surface. Lower the blade completely to the ground to relieve all hydraulic pressure. Engage the parking brake and block the tracks.
Controlled Disassembly: Disconnect and cap hydraulic lines. Properly support the cylinder rod before removing the mounting pins. Note the orientation and order of all components.
Cleanliness Protocol: Disassembly and assembly must be performed in a clean area. Thoroughly clean all metal components and the workbench to prevent contamination.
Critical Metal Inspection: Inspect the cylinder rod for any scratches, gouges, or corrosion. Check the cylinder bore (ID) for scoring, pitting, or excessive wear. Damaged metal components must be replaced prior to seal installation.
Lubricated Assembly: Soak all new elastomeric seals in clean hydraulic fluid. Lightly lubricate all seal grooves and sliding surfaces before installing new seals.
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 torque wrench to tighten all bolts, gland nuts, or end caps to Komatsu's specified torque values and sequences.
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