Technical Constants & Performance Data
| Parameter | Value / Specification |
|---|---|
| Maximum System Pressure | Up to 5,220 PSI (360 bar) |
| Temperature Range | -40°F to 225°F (-40°C to 107°C) |
| Fluid Compatibility | Mineral-based hydraulic oils, Komatsu Super Hydraulic Fluid (KSHV), synthetic HFDU fluids |
| Primary Seal Material | Polyurethane (AU), Cast Polyurethane (CU), Nitrile Rubber (NBR) |
| Seal Hardness (Dynamic) | 92-95 Shore A (Polyurethane Main Seals) |
| Seal Hardness (Static) | 70 Shore A (NBR O-Rings) |
| Design Standard | Manufactured to meet or exceed Komatsu DHTA (Dantotsu High-Tech Advance) specifications for durability in high-pressure, high-shock applications. |
Exact Model Compatibility
| Komatsu Machine Model | Specific Cylinder Application |
|---|---|
| Komatsu PC300LC-8 | Bucket Cylinder |
| Komatsu PC350LC-8 | Bucket Cylinder |
| Note: | This kit is a direct replacement for Komatsu OEM part number 707-52-90300. It is designed specifically for the BUCKET CYLINDER on the listed 30-35 ton class excavator models. Always verify you machine's model, serial number, and that you are servicing the BUCKET CYLINDER (not the boom or arm cylinder) before disassembly. |
Component Specifications Table
| Component Name | Material | Color | Durometer | Function |
|---|---|---|---|---|
| Main Piston Seal (U-Cup) | Polyurethane (AU) | Brown | 95 Shore A | Primary high-pressure dynamic seal on piston |
| Rod Seal (Step Seal) | Cast Polyurethane (CU) | Black | 93 Shore A | Main rod seal for pressure retention & low friction |
| Wiper/Scraper (Heavy-Duty) | Polyurethane (PU) | Black | 90 Shore A | Excludes abrasive dirt and moisture from rod surface |
| Buffer Ring | Polyurethane (CU) | Black | 90 Shore A | Protects rod seal from pressure spikes during digging impacts |
| O-Ring Set (Assorted) | Nitrile Rubber (NBR) | Black | 70 Shore A | Static sealing for gland assembly, port connections, plugs |
| Wear Ring / Guide Band | Glass-Filled PTFE | Dark Brown | N/A | Guides piston, absorbs sideloads, prevents metal contact |
| Backup Rings | Nylon 6.6 | Tan | N/A | Prevents extrusion of static O-rings under extreme pressure |
Specific Components Included
Main Piston Seal (U-Cup) – Qty: 1
Rod Seal (Step Seal) – Qty: 1
Wiper/Scraper – Qty: 1
Buffer Ring – Qty: 1
Wear Ring (Piston) – Qty: 1
Complete O-Ring & Backup Ring Set – Qty: 1 Set (All necessary sizes for gland and SAE port assembly)
Note: This kit provides a complete seal profile set designed to match the exact specifications of the original Komatsu 707-52-90300 bucket cylinder kit. An exploded diagram is included for correct assembly.
Decompose pictures
Parts list
|
NO |
Number |
Name |
Qty |
|
134-63-01013 |
CYLINDER ASS'Y |
2 |
|
|
1 |
134-63-12042 |
• CYLINDER |
1 |
|
2 |
07143-10606 |
• BUSHING |
1 |
|
3 |
07145-00060 |
• SEAL,DUST (KIT) |
2 |
|
4 |
707-29-11620 |
• HEAD,CYLINDER |
1 |
|
5 |
707-52-90300 |
• BUSHING |
1 |
|
6 |
707-51-55030 |
• PACKING,ROD (KIT) |
1 |
|
7 |
707-51-55640 |
• RING,BUFFER (KIT) |
1 |
|
8 |
707-56-55540 |
• SEAL,DUST (KIT) |
1 |
|
9 |
07179-12069 |
• RING,SNAP |
1 |
|
10 |
07000-12105 |
• O-RING (KIT) |
1 |
|
11 |
07146-02106 |
• RING,BACK-UP (KIT) |
1 |
|
12 |
07000-12110 |
• O-RING (KIT) |
1 |
|
13 |
134-63-12020 |
• ROD,PISTON |
1 |
|
14 |
07143-10606 |
• BUSHING |
1 |
|
15 |
07145-00060 |
• SEAL,DUST (KIT) |
2 |
|
16 |
707-36-11040 |
• PISTON |
1 |
|
17 |
707-44-11180 |
• RING,PISTON (KIT) |
1 |
|
18 |
07156-01112 |
• RING,WEAR (KIT) |
1 |
|
19 |
707-67-39010 |
• NUT |
1 |
|
K |
707-99-34600 |
SERVICE KIT |
2 |
Installation decomposition diagram
Safe Depressurization & Support: Park the excavator on level ground. Lower the bucket fully to the ground to relieve all hydraulic pressure. Mechanically block the bucket or cylinder rod to prevent any movement.
Ultra-Clean Environment: Perform all work in a meticulously clean, dust-controlled area. Bucket cylinders are highly susceptible to abrasive contamination. Use a parts washer, clean solvent, and lint-free cloths.
Documented Disassembly: Carefully disassemble the cylinder gland. Photograph and label each component and its precise orientation. Note the exact stacking order of all seals and spacers in the gland.
Mandatory Metal Inspection: Use a micrometer to inspect the cylinder rod for scratches, pitting, or scoring. Inspect the cylinder bore (ID) for wear, tapering, or scoring. Damaged metal components must be replaced.
Proper Seal Installation: Soak all new elastomeric seals in clean hydraulic fluid. Use seal installation cones, sleeves, and nylon picks designed for large diameters. Never use sharp metal tools that can nick seals.
Precision Reassembly: Follow the included diagram exactly for seal order and orientation. Ensure each seal is fully and squarely seated in its groove before proceeding to the next.
Torque Specifications: Use a calibrated torque wrench. Adhere strictly to Komatsu's specified torque values and sequences for gland bolts or tie-rods. Use a criss-cross pattern for even flange compression.
Frequently Asked Questions
A. When will get the items after I place order?
Q. Once your payment is confirmed,we will arrange the goods within 1~4 days; if not in stock, we will inform you before placing the order?
A. If I only know the excavator model, but can not offer parts No.,what should I do ?
Q. If possible, you can send us pictures of old products, nameplate or the size for reference.
A. How can you guarantee the quality??
Q. We will 100% test the goods before delivery. We also support video inspection.
A. How long will it take to delivery to my address??
Q. The normal delivery time is 3-7 days, depending on which country you are in.?
A : Which delivery method will you choose?
Q : By sea, air or express(DHL,Fedex,TNT, UPS, EMS etc.)，Sometimes we will arrange as the customer's demand.
A: What's package? Can you give me the package according my requirement??
Q. We usually packed by standard exported box or carton. And yes we can pack as per your requirement.
A: Can the price be cheaper?
Q: Of course, you will be offered a good discount for a big amount.
A: Why should I choose to buy from you?
Q:Our advantages: 100% quality assurance, develop and manufature follow original ones;Quick response within 24 hours; Small order allowed;Reasonable stock and timely delivery;Neutral packing, customized packing are allowed. Positive customer feedback from abroad market;Excellent after-sales service.
A : Which payment terms can you accept?
Q : Paypal. Western Union, Bank Transfer, T/T...
Contact COGENG
📞 Phone: +86-185-2913-1515 🌐 Instagram
📧 Email: hugo@cogeng.net 🌐 Facebook：Excavator Parts Selection and Replacement Community
💬 WhatsApp +86-185-2913-1515 Facebook: Excavator Wiring Harness
💬 WeChat: +86-185-7865-1106 Facebook: Excavator Wire Harness
🌐 Website: cogeng.net Facebook: Excavator SolenoidValve
