Technical Constants & Performance Data
| Parameter | Value / Specification |
|---|---|
| Maximum Operating Pressure | Up to 3,045 PSI (210 bar) |
| Temperature Range | -40°F to 225°F (-40°C to 107°C) |
| Fluid Compatibility | Mineral-based hydraulic oils, Komatsu-approved fluids, standard AW/HLP fluids |
| Primary Seal Material | Polyurethane (AU), Cast Polyurethane (CU), Nitrile Rubber (NBR) |
| Seal Hardness (Dynamic) | 90-94 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 forklift applications. |
| OEM Part Number | 707-98-50100 / 7079850100 |
| Brand | COGENG (Premium Aftermarket) |
| Compatible Models | Komatsu D60S-7, D60S-8 Forklifts |
| Cylinder Application | Dump Cylinder / Tilt Cylinder |
| Service Type | Heavy-Duty Hydraulic Cylinder Rebuild |
Exact Model Compatibility
| Komatsu Forklift Model | Specific Cylinder Application |
|---|---|
| Komatsu D60S-7 | Dump (Tilt) Cylinders |
| Komatsu D60S-8 | Dump (Tilt) Cylinders |
| Note: | This kit is a direct replacement for Komatsu OEM part number 707-98-50100. It is designed specifically for the DUMP/TILT CYLINDERS on the listed forklift models. Verify your machine's model, serial number, and that you are servicing the DUMP CYLINDERS, not the lift or power steering 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 | 92 Shore A | Main rod seal for pressure retention |
| Wiper/Scraper | Polyurethane (PU) | Black | 90 Shore A | Excludes dirt, dust, and moisture from rod |
| Buffer Ring | Polyurethane (CU) | Black | 90 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 | 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 |
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 port assembly)
Note: This kit provides a complete seal profile set designed to match the exact specifications of the original Komatsu 707-98-50100 dump cylinder kit. An exploded diagram is included for correct assembly.
| Step | Action | Critical Note |
|---|---|---|
| 1 | Lower forks fully, relieve hydraulic pressure | Safety first |
| 2 | Disconnect hydraulic hoses | Cap fittings to prevent contamination |
| 3 | Remove cylinder from forklift | Support properly |
| 4 | Disassemble cylinder | Note seal orientation before removal |
| 5 | Clean all components | Use clean rags; no debris allowed |
| 6 | Inspect cylinder bore | Must be smooth (0.2-0.4 μm Ra) |
| 7 | Inspect rod surface | Must be scratch-free, chrome intact |
| 8 | Lubricate new seals | Use clean hydraulic oil |
| 9 | Install seals in correct orientation | Pay attention to lip direction |
| 10 | Assemble cylinder | Torque end cap to specification |
| 11 | Pressure test | 1.5x working pressure for 5 minutes |
| 12 | Reinstall on forklift | Test operation |
Support Seals & Hardware
Full set of precision-molded static O-rings for all gland and port connections.
Essential wear guide band to ensure smooth piston travel and minimize side load on seals.
Required 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.
Installation decomposition diagram
Installation Guidelines & Critical Procedures
Machine Secure & Pressure Relief: Park the forklift on level ground. Lower the mast completely and tilt the carriage forward to relieve hydraulic pressure. Engage the parking brake and block the wheels.
Cleanliness Protocol: Disassembly and assembly must be performed in a clean environment. Forklift cylinders operate in dusty warehouses; contamination control is essential.
Documented Disassembly: Carefully disassemble the dump 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 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 calibrated torque wrench. Adhere strictly to Komatsu's specified torque values and sequences for gland bolts or end caps.
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...
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