The Crossover Relief Valve (XOV) protects the snow plow system against damaging forces under normal snow plowing conditions. When plowing, the system can be exposed to damaging forces caused by impact with hidden obstructions, ends of curbs, etc. With power angling, these forces can damage not only the snow plow but also the vehicle. The Spring is the most likely part to fail on the valve. The Seals should be replace when the valve is removed. Spring is made to Original Specifications - Not a Reverse Engineered Approximation