The COGENG 707-52-11011 Cylinder Seal Kit is a premium-grade, OEM-replacement sealing solution meticulously engineered for Komatsu hydraulic excavator cylinders. This comprehensive kit contains every precision-molded sealing component required to fully rebuild a hydraulic cylinder—restoring it to factory-fresh performance, eliminating internal and external leakage, and ensuring safe, reliable operation across the most demanding job-site conditions. Designed as a direct replacement for the original Komatsu part number 707-52-11011, this kit is the preferred choice for workshop overhauls, field repairs, and preventive maintenance programs worldwide.
Hydraulic cylinder seal degradation is a primary cause of reduced machine productivity, increased fuel consumption, and erratic attachment control. Worn seals allow pressurized oil to bypass the piston, resulting in boom drift, sluggish arm response, and bucket curl weakness—all of which compromise operator safety and job-site efficiency. The COGENG 707-52-11011 kit addresses these issues comprehensively, providing a full set of rod seals, piston seals, wiper seals, O-rings, backup rings, and wear guides, all manufactured to dimensional tolerances that match or exceed Komatsu's original specifications.
Each seal in the COGENG 707-52-11011 kit is crafted from advanced polymeric materials selected for their specific functional requirements. The urethane rod seals offer exceptional abrasion resistance, low friction, and high extrusion resistance, ensuring long service life even under high-pressure, high-cycle conditions. The nitrile rubber (NBR) O-rings and backup rings provide reliable static sealing across a wide temperature range, while the fabric-reinforced phenolic wear guides minimize metal-to-metal contact, protecting both the piston and cylinder bore from premature wear. All components are 100% dimensionally inspected and functionally validated before packing, ensuring that every kit delivers consistent, leak-proof performance from the moment of installation.
By choosing COGENG for your cylinder seal needs, you are investing in a product that prioritizes quality, reliability, and safety. With global inventory, rapid shipping, and responsive technical support, COGENG keeps your Komatsu excavator fleet operating at peak productivity—reducing downtime, lowering maintenance costs, and providing peace of mind on every job.
| Figure | Description |
|---|---|
| Figure 1 | Complete kit overview – Top-down layout photograph showing every component of the 707-52-11011 kit arranged in functional groups: rod seals (U-cups), piston seals (double-acting rings), wiper seals (scrapers), O-rings, PTFE backup rings, and fabric-reinforced wear guides (bearing rings). |
| Figure 2 | Rod seal cross-section diagram – Detailed illustration of the urethane U-cup seal profile, showing the dynamic sealing lip, static heel, and pressure-activated lip geometry that ensures leak-free rod sealing under high pressure. |
| Figure 3 | Piston seal assembly view – Exploded diagram of the piston area, depicting the installation sequence of the O-ring, PTFE backup rings (both sides), and the main piston seal rings within the piston grooves. |
| Figure 4 | Wiper (scraper) seal close-up – Highlighting the unique lip design that effectively removes dirt, dust, moisture, and ice from the rod surface during retraction, preventing external contaminants from entering the hydraulic system. |
| Figure 5 | Cylinder bore and rod orientation – Cross-sectional schematic of a complete cylinder assembly, indicating the exact placement of each seal type within the gland (head), piston, and along the rod. |
| Figure 6 | Color-coded component identification chart – Reference guide matching each seal to its corresponding groove location, with dimensions (OD, ID, cross-section) noted for verification against your old seals. |
| Figure 7 | Wear guide (bearing ring) detail – Shows the fabric-reinforced phenolic composite ring, which provides low-friction support to the piston and rod, absorbing radial loads and preventing metal scoring. |
| Figure 8 | Installation sequence infographic – Step-by-step visual guide showing the correct order of assembly, with cautionary notes on sharp edges, thread protection, and proper lubrication points. |
The COGENG 707-52-11011 Cylinder Seal Kit is compatible with a broad range of Komatsu excavator models, specifically designed for standard boom, arm, and bucket cylinders with a specific bore and rod diameter configuration. This kit is also suitable for certain attachment cylinders (e.g., tilt, thumb, hydraulic quick-coupler) that share the same sealing architecture. Always confirm your cylinder's dimensions and original part number before ordering.
| Komatsu Model | Series Range | Typical Cylinder Application |
|---|---|---|
| PC200-5 / -6 / -7 / -8 | Standard hydraulic excavator | Boom cylinder, Arm cylinder, Bucket cylinder |
| PC210-5 / -6 / -7 / -8 | Heavy-lift variant | Boom cylinder (reinforced), Arm cylinder |
| PC220-5 / -6 / -7 / -8 | Mass excavation model | Bucket cylinder, Arm cylinder |
| PC240LC-5 / -6 / -7 / -8 | Large chassis / heavy undercarriage | Boom cylinder, Attachment cylinder |
| PC270-5 / -6 / -7 | High-power class | Arm cylinder, Tilt bucket cylinder |
| PC300-5 / -6 / -7 | 30-ton class excavator | Boom cylinder (partial compatibility – verify bore) |
| PC350-5 / -6 / -7 | Quarry / mining excavator | Bucket cylinder (check serial prefix) |
| PC400-5 / -6 | Large mining excavator | Arm cylinder (specific production dates) |
| WA320 / WA380 (Wheel Loaders) | Komatsu wheel loader series | Steering cylinder, Lift cylinder (limited cross-fit) |
Note: This kit is primarily designed for Komatsu cylinders with a nominal bore diameter of approximately 110–125 mm and rod diameter of 65–75 mm. For machines with larger or smaller cylinders, or for cylinders with non-standard groove configurations, please contact COGENG with your cylinder serial number and original seal measurements for exact cross-referencing.
Installation Steps (Visual Summary):
Safe disassembly and preparation – Position the cylinder securely on a clean, flat workbench using suitable supports. Relieve all hydraulic pressure by cracking open the work ports (collect draining oil). Remove the cylinder head gland using a pin spanner or appropriate wrench.
Rod and piston extraction – Carefully pull the piston rod assembly from the barrel. Support the rod evenly along its entire length to prevent bending or scratching the chrome-plated surface. Use a sling or overhead hoist for larger cylinders.
Complete disassembly – Remove the gland from the rod, then detach the piston from the rod (note the retaining nut torque for reassembly). Remove all old seals, O-rings, backup rings, and wear guides from the piston and gland.
Thorough cleaning and inspection – Clean every groove and surface with a non-abrasive solvent and lint-free cloth. Inspect the cylinder bore for scoring, pitting, or out-of-round conditions. Inspect the rod for scratches, chrome flaking, or corrosion. If either is damaged beyond acceptable limits, the cylinder must be re-machined or replaced—installing new seals into a damaged bore or rod will result in rapid failure.
Old seal comparison – Lay your old seals alongside the new COGENG components. Verify that all dimensions (OD, ID, cross-section width) match. Pay special attention to the rod seal lip orientation and the piston seal ring profile.
Install piston seals – Lubricate all new seals with clean hydraulic oil. Install the O-ring into the inner piston groove, then fit the PTFE backup rings on both sides. Install the main piston seal rings (double-acting type) into their respective outer grooves, ensuring the lip faces the correct pressure direction.
Install gland seals – Into the clean gland housing, install the rod U-cup seal (lip facing inward toward the pressure chamber). Install the O-ring and backup ring in their designated grooves. Finally, press the wiper seal into the outer gland groove (lip facing outward to scrape contaminants from the rod).
Assemble piston to rod – Slide the piston onto the rod. Apply a thin film of oil to the threads, then torque the retaining nut to the manufacturer's specification (typically 250–450 N·m depending on cylinder size—consult your machine service manual). Use a torque wrench and, if applicable, a hydraulic torque multiplier.
Reinsert piston assembly – Guide the piston and rod assembly carefully back into the cylinder barrel. Use a seal installation sleeve or tapered guide to prevent the new rod seal and piston seals from being nicked or rolled on the barrel threads or port edges. Slow, steady insertion is critical.
Reinstall gland – Thread the gland onto the barrel (or onto the rod, depending on cylinder design). Torque to specification. Install any retaining screws, snap rings, or lock wires as per the original configuration.
Function test and purging – After reinstallation on the machine, start the engine and idle for 2 minutes. Cycle the cylinder slowly through 5–10 full strokes (extension and retraction) to purge trapped air and allow the new seals to seat properly. Inspect for any external leakage around the gland. Re-torque all fasteners after the first heat cycle if required.
| Important Consideration | Detail |
|---|---|
| OEM Cross Reference | Direct replacement for Komatsu genuine part number 707-52-11011. Also supersedes 707-52-11000 and certain 707-52-10xxx series kits. Always cross-reference with your old kit's contents and the cylinder's identification tag. |
| Cylinder Bore Range | Designed for cylinders with bore diameters from 110 mm to 125 mm (4.33"–4.92"). Measure your cylinder bore accurately before ordering to confirm fitment. |
| Rod Diameter Range | Suitable for rod diameters of 65 mm, 70 mm, or 75 mm (2.56", 2.76", 2.95") depending on the specific kit variant. Verify your rod size by direct measurement or from the cylinder datasheet. |
| Pressure Rating | All seals are rated for continuous operation at 34.3 MPa (4,970 psi) and intermittent peaks up to 39.2 MPa (5,680 psi)—suitable for standard and high-pressure Komatsu hydraulic systems. |
| Temperature Range | Operating range: –40 °C to +110 °C (–40 °F to +230 °F) for standard NBR/O-ring components. For extreme cold (< –40 °C) or high-heat applications (>100 °C continuous), contact COGENG for special material options (HNBR, FKM, or custom urethane compounds). |
| Fluid Compatibility | Compatible with standard petroleum-based hydraulic oils (ISO VG 32, 46, 68) and most biodegradable fluids (HEES, HETG, HEPS). Not recommended for water-glycol (HFC) or phosphate-ester (HFDR) fluids without prior validation and seal material adjustment. |
| Surface Finish Requirement | For optimal seal life and leak-free performance, the cylinder bore should have a surface finish of Ra 0.2–0.4 µm and the rod a finish of Ra 0.1–0.3 µm. Rough, scored, or corroded surfaces will significantly shorten seal life. |
| Installation Lubrication | Use only clean hydraulic oil or a dedicated cylinder assembly grease (e.g., Kluber Isoflex). Never use petroleum jelly, molybdenum disulfide, or zinc-based pastes—these can cause swelling or chemical degradation of urethane and rubber components. |
| Storage Life | 5 years when stored in original packaging in a cool, dry environment (10–30 °C, <60% RH), away from ozone sources (electric motors, welding equipment) and direct sunlight. |
| Cylinder Type | This kit is designed for double-acting hydraulic cylinders with standard groove configurations. For single-acting, telescopic, or cushion-type cylinders, please consult COGENG for a custom-kit solution. |
| Shipping Detail | Description |
|---|---|
| Shipping Methods | By Air, By Sea, By Express (FedEx, UPS, DHL, TNT, etc.). The specific arrangement will be based on the cargo situation and destination. |
| Estimated Delivery Time | Based on the shipping time of the logistics company. The arrival time shown by the carrier's tracking system shall prevail. |
| Packing | Inner: Sealed anti-static plastic bag with desiccant and oxygen absorber. Outer: Reinforced 5-layer corrugated carton with custom-cut foam inserts—individual seal types are separated by partition cards to prevent abrasion and deformation during transit. For bulk orders, wooden crates with internal bracing are used. |
| Payment Terms | Western Union, L/C (Letter of Credit), T/T (Telegraphic Transfer), MoneyGram, D/A (Documents against Acceptance), D/P (Documents against Payment) |
| Return Policy Point | Terms |
|---|---|
| Merchant Return Policy | Products shipped are not returnable or exchangeable. |
| Quality Guarantee | Every seal component is 100% inspected for dimensional accuracy (using optical comparators and laser micrometers), material hardness (Shore A), and tensile strength. Complete kits are assembled and counted twice—ensuring no missing components. A Certificate of Conformance (CoC) with full test data is available upon request. Our rigorous quality protocol guarantees a DOA (Dead on Arrival) rate of under 0.01%. |
| Pre-Shipment Confirmation | Photos of the complete kit layout and individual component measurements can be provided upon request before shipment to confirm correct part numbers and operational condition. We strongly recommend providing your old seal set (or detailed measurements) for positive cross-reference prior to ordering. |
Q1: What components are included in the COGENG 707-52-11011 seal kit?
A: This comprehensive kit includes: one U-cup rod seal, one or two double-acting piston seal rings (depending on piston type), one wiper (scraper) seal, all required O-rings (typically 4–6 pieces), PTFE backup rings (for both static and dynamic applications), and fabric-reinforced phenolic wear guides (bearing rings). The exact component count varies slightly by cylinder configuration—contact us for a detailed list specific to your cylinder model.
Q2: How do I verify if this kit fits my Komatsu PC220 arm cylinder?
A: First, check the identification tag on your cylinder (usually stamped on the barrel or gland). If the OEM part number is 707-52-11011, this is a direct match. Alternatively, measure the cylinder bore diameter (internal) and rod diameter (external chrome surface). For this kit, the typical dimensions are bore 115–120 mm and rod 65–70 mm. Send these measurements, along with a photo of your old seals, to our technical team for a definitive verification.
Q3: Can I install these seals without removing the cylinder from the machine?
A: While some cylinder gland repairs can be performed in situ (with the cylinder still mounted), we strongly recommend removing the cylinder for a full overhaul. In-frame repairs do not allow proper cleaning, bore inspection, or torquing of the piston nut—leading to a high risk of premature failure.
Q4: What is the expected service life of these seals under normal operating conditions?
A: Under standard duty cycles (8–10 hours/day, clean hydraulic oil ISO 4406 18/16/13 or better), these seals typically deliver 4,500–6,500 hours of reliable service. In harsh conditions (high contamination, extreme temperatures, rapid cycling), inspect at 1,000-hour intervals and replace at the first sign of leakage or performance degradation.
Q5: Do I need any special tools to install this seal kit?
A: Basic hand tools (wrenches, sockets, torque wrench) are required for cylinder disassembly and reassembly. For seal installation, we recommend: (a) a seal installation cone or tapered sleeve to protect lip seals during insertion; (b) plastic or brass drift tools for seating O-rings without scratching grooves; (c) a digital caliper for final dimension verification. Most of these are available from COGENG upon request.
Q6: Are the seals in this kit compatible with synthetic hydraulic oils?
A: Yes—the NBR (nitrile) O-rings and polyurethane seals are compatible with most synthetic hydrocarbon-based hydraulic fluids, including PAO (polyalphaolefin) and diester types. However, for fully synthetic esters (e.g., pentraerythritol esters) or fire-resistant fluids, we recommend upgrading to HNBR or FKM seals—please consult COGENG technical support.
Q7: Is this kit an OEM Komatsu product, or is it an aftermarket equivalent?
A: COGENG is an independent aftermarket manufacturer, not affiliated with Komatsu. However, our seals are engineered to exact OEM specifications using premium materials sourced from global leaders. All critical performance parameters (compression set, tensile strength, abrasion resistance, extrusion resistance) are independently validated to meet or exceed genuine Komatsu requirements.
Q8: What should I do if the kit arrives with a component missing or damaged?
A: Though we conduct 100% double-counting during packing, in the unlikely event of a shortage or transit damage, contact COGENG immediately with your order number and clear photos. We will dispatch replacement components at no extra charge via express shipping.
For pricing, bulk orders, or technical support, contact your COGENG supplier today.
Please provide your machine model and cylinder serial number for compatibility verification.
Sales Price: Please contact COGENG sales customer service for specific prices.
Shipping method: The specific arrangement will be based on the cargo situation.
Estimated delivery time: It is based on the shipping time of the logistics company, and the arrival time shown shall prevail.
Contact details are at the bottom of this datasheet.
| Feature | Benefit |
|---|---|
| ✅ OEM Replacement | Direct fit for Komatsu 707-52-11011—no modifications, no adapters, no guesswork |
| ✅ Premium Quality | Advanced polyurethane, NBR, and PTFE materials engineered for leak-proof, long-life performance |
| ✅ Leak-Proof Design | Precision-molded lips and exact groove geometry eliminate internal bypass and external drips |
| ✅ Built for Job Site Durability | Withstands extreme pressure (35+ MPa), temperature cycling (-40°C to +110°C), and heavy contamination—field-tested in quarry, mining, and demolition applications |
| ✅ In Stock — Fast Shipping Worldwide | Available from regional warehouses; express shipping options for emergency repairs |
| ✅ Pre-shipment Verification | Photos, measurement reports, and kit layout confirmation available—order with absolute confidence |
| ✅ Non-returnable but Quality-Backed | Every component 100% inspected and kits double-counted before packing—DOA risk effectively eliminated |
| Parameter | Specification |
|---|---|
| Kit Net Weight | Approx. 1.15 kg (varies by cylinder size configuration) |
| Rod Seal Type | U-cup with dynamic pressure-activated lip, cast polyurethane (92 Shore A) |
| Piston Seal Type | Double-acting ring set with PTFE anti-extrusion rings (both sides) |
| Wiper Seal Type | Single-lip scraper, fabric-reinforced NBR (80 Shore A) |
| O-Ring Material | NBR 70 Shore A (standard); HNBR optional for high-temperature applications |
| Backup Ring Material | PTFE (polytetrafluoroethylene) with 15% glass fiber for enhanced creep resistance |
| Wear Guide Material | Phenolic resin with woven cotton fabric—low friction coefficient, high load capacity |
| Maximum Operating Pressure | 35 MPa (5,076 psi) continuous; 40 MPa (5,800 psi) peak |
| Maximum Rod Speed | 0.5 m/s for rod seal; 0.3 m/s for piston seal |
| Fluid Compatibility | ISO 6743/4 HM, HV, HLP (mineral oils); HEES, HETG (biodegradable) |
| Hardness Tolerance | ±5 Shore A for all rubber components |
| Compression Set (NBR) | ≤ 15% after 70 hours at 100°C (per ASTM D395) |
| Tensile Strength (Urethane) | ≥ 35 MPa (per ASTM D412) |
| Abrasion Resistance | ≤ 25 mm³ volume loss (per DIN 53516) |
| Shelf Life | 5 years in original unopened packaging |
| Packaging Dimensions | 440 × 320 × 85 mm (standard carton) |
| Country of Origin | Manufactured in ISO 9001:2015 / IATF 16949 certified facility |
| Certification | REACH, RoHS, and Conflict Minerals compliant; material certificates available on request |
This datasheet is for informational purposes only. COGENG reserves the right to improve specifications without prior notice. Always refer to the product label and the installation leaflet included with each seal kit. For cylinders with non-standard dimensions, special groove configurations, or custom pressure requirements, please contact our technical support team for engineering consultation. Proper cylinder preparation—including bore honing, rod re-chroming, and surface finish verification—is essential for achieving maximum seal life and leak-free performance.
*shipping Details Return Sales*
Sales price:
Please contact COGENG sales customer service for specific prices.
Shipping method:
The specific arrangement will be based on the cargo situation.
Estimated delivery time:
It is based on the shipping time of the logistics company, and the arrival time shown shall prevail.
Contact details are at the bottom.
MerchantReturnPolicy:
The products shipped are not returnable or exchangeable.
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