Back-up ring for Terex RT-130

The 208404 back-up ring serves as an auxiliary component within hydraulic and pneumatic sealing systems. Its primary function is to provide mechanical support to primary seals, such as O-rings, preventing them from extruding into the clearance gap between mating surfaces under high-pressure conditions. By maintaining the position and shape of the primary seal, this component helps preserve the overall integrity of the hydraulic circuit.

This part is compatible with several Terex crane models, including the RT-130, T300, and T340-1XL. It is typically utilized within hydraulic cylinders for booms, outriggers, and steering actuators where seals are subjected to significant operational loads. The design ensures proper fitment within these specific hydraulic assemblies to support the sealing arrangement effectively.

Back-up rings are used in hydraulic systems to bridge the gap between moving parts, which prevents the primary seal from being forced into the clearance space. When a system operates under high pressure, the primary seal may deform or extrude; the back-up ring acts as a rigid or semi-rigid barrier that maintains the seal's geometry. Proper installation of these rings is necessary to ensure the hydraulic system remains pressurized and free from fluid leaks during operation.