Background A heavy machinery manufacturer in East China faced frequent medium leakage in its core hydraulic equipment, with failures occurring 2-3 times per month. This led to recurrent downtime and rising production costs. Analysis identified rapid aging of traditional seals under high-pressure impact and oil temperature fluctuations as the root cause. Solution The technical team implemented a multi-layer composite sealing structure: A hydrogenated nitrile rubber main body for oil resistance and elasticity An embedded aramid fiber reinforcement layer to withstand high-pressure deformation A PTFE coating on the surface to reduce the friction coefficient The solution was paired with laser-measurement installation to achieve micron-level assembly precision. Results Continuous operation extended from 72 to 2,000 hours Leakage incidents reduced by 94% Annual maintenance costs lowered by RMB 370,000 Recognized with the enterprise’s Annual Technological Innovation Award Key Insight This case demonstrates that customized sealing design and precision installation tailored to specific operating conditions can fundamentally resolve persistent leakage—providing critical technical support for full lifecycle equipment management. Though a small component, seals serve as a vital line of defense for the reliable operation of modern industrial systems.