When an original equipment front strut and spring assembly fails on certain GMC, Chevrolet and Cadillac SUVs and trucks equipped with magnetic ride control, it's often due to fluid leaks that develop in the strut's top seal assembly. Over time and miles, the factory seals deteriorate from the friction, heat and fluid pressure generated during every compression and rebound cycle of the strut. Ultimately that continuous cyclic load leads to seal failure and with it a loss of damping effectiveness and overall suspension performance, and potentially a failed state inspection. This Dorman OE FIX loaded magnetic strut assembly features an innovative upgraded top seal design that prevents this common and costly cause of strut failure. Our patent-pending top seal block assembly absorbs impact pressure better by more effectively and efficiently relieving and restoring cyclic fluid pressure on demand, virtually eliminating the relentless and damaging internal fluid pressurization inherent in the original equipment's design. In addition, this assembly features more durable mounting points to help ensure long service life under the toughest conditions. And because this is a pre-assembled loaded assembly, installation does not require the risk and hassle of using a spring compressor.