Back-up ring for Terex cranes

The back-up ring, part number 45Z568D3, serves as an auxiliary component within the hydraulic sealing systems of heavy machinery. Its primary function is to provide mechanical support to O-rings and other dynamic seals. By positioning itself on the low-pressure side of the seal, the ring prevents the seal material from extruding into the clearance gap between mating parts when the system operates under high pressure.

This component is engineered for compatibility with Terex cranes. These machines, which include rough-terrain, crawler, and truck-mounted variants, rely on high-pressure hydraulic circuits for cylinders, valves, and actuators. The back-up ring ensures that the primary seals maintain their position and integrity during operation.

Back-up rings function by bridging the extrusion gap that exists between moving or static machine components. By occupying this space, they allow the primary seal to maintain its shape and sealing contact without being forced out of its groove. This support is necessary in hydraulic systems where pressure levels would otherwise cause soft seal materials to deform and fail, leading to fluid leaks and loss of system pressure.