The dynamic inner sealing elements are injection-molded from a highly cross-linked, high-density Nitrile Butadiene Rubber (NBR). This optimized elastomeric matrix is strictly engineered to handle continuous exposure to standard API GL-4 and GL-5 gear oils, hydraulic fluids, and wet-brake lubricants at operating temperatures up to 100°C (212°F). The thick NBR matrix actively resists the physical tearing, chunking, and dry-rot that destroy standard automotive seals in agricultural settings.

From a heavy-equipment maintenance perspective, installing a deep 16mm Combi seal requires precise mechanical alignment. Because of the exposed steel case, the seal must be driven perfectly square into the 52mm bore.

Critical Assembly Note: You must heavily pack the internal cavity between the primary oil lip and the outer dirt excluder with a high-quality, waterproof marine or agricultural lithium-complex grease prior to assembly.

This grease packing serves two critical engineering functions: it provides essential boundary lubrication to prevent the outer dirt lips from burning up during dry field transport, and it acts as an additional physical barrier to block the ingress of dirty water. Furthermore, technicians must meticulously inspect the 35mm axle shaft; any severe grooving from the previous failed seal will require the installation of a stainless steel wear sleeve (speed sleeve) to provide a smooth, 0.2 to 0.4 μm Ra surface finish for the new Combi lips to ride against.