The E8TZ-5A978-A Rear Spring Insulator is a direct-fit replacement designed for Ford F-350, F-450, and F-550 Super Duty trucks (1988–2025). Installed between the rear leaf spring and suspension bracket, this part plays a critical role in reducing noise, vibration, and wear.
Made from high-strength EPDM rubber, the insulator offers excellent elasticity, weather resistance, and long-term durability. It prevents metal-to-metal contact, protecting both the spring and mounting surfaces from friction damage. By absorbing shock and cushioning impact, it also improves overall ride comfort and stability under load.
Each vehicle typically requires four insulators to fully restore the suspension's quiet, smooth, and reliable function. Precision-molded to match factory specifications, this insulator provides a secure fit and dependable performance, helping extend the life of your suspension system