128-9656 1289656 PU PTFE Composite Piston Seal for Construction Excavator Hydraulic Cylinder Repair 12H 140H 120H

1. Quick Details of  seal 128-9656:

2.  128-9656 picture:

3. Service part number :

4. FAQ

Q: What advantages does the three-layer composite structure of PU, PTFE and NBR bring to piston sealing?
A: Excavator hydraulic cylinders work under long-term high pressure and frequent reciprocating friction. PU main seal has ultra-high wear resistance and strong pressure bearing capacity, not easy to deform under long-term hydraulic impact. The outer PTFE ring reduces friction between seal and cylinder barrel, lowering operating noise and reducing barrel scratch wear. The built-in NBR elastic ring provides lasting radial tension to keep the seal tightly fitted to the cylinder wall, avoiding internal oil leakage of the cylinder.

Q: What color and structural features do each layer of this piston seal have?
A: The outer PU main sealing body is bright orange, with integrated double-lip sealing structure and smooth surface. The middle PTFE anti-extrusion ring is milky white thin flat ring, closely attached to the PU groove. The inner NBR elastic supporting ring is solid black round ring, with uniform elasticity. The three parts are pre-assembled as a whole, which is convenient for on-site installation without separate matching.

Q: What pressure and temperature range can this piston seal adapt to?
A: The composite piston seal can continuously bear working pressure up to 400bar, and adapts to the temperature range of -35°C to +120°C. It can work stably in low-temperature outdoor construction in winter and continuous high-load operation in summer without lip peeling or elastic failure.

Q: What hidden failures will inferior piston seals bring to hydraulic cylinders?
A: Low-cost piston seals use inferior recycled PU without PTFE protective layer. They wear quickly after reciprocating friction, leading to internal oil leakage of the cylinder. The cylinder will have weak power, slow action and shaking during operation. Severe wear debris will scratch the inner wall of the cylinder barrel, resulting in expensive cylinder barrel replacement costs and long equipment downtime.

Q: What key installation specifications should operators follow to extend the service life of the piston seal?
A: First, clean the piston groove and cylinder inner wall thoroughly to remove metal particles and old seal residues. Second, lubricate the whole seal with clean hydraulic oil before installation, do not use thick grease. Third, use a special installation tool to push the seal evenly into the piston groove, avoid twisting or scratching the PU lip. Fourth, check that the PTFE ring is completely embedded without warping before loading the piston into the cylinder barrel.

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