8-031 BLACK FKM 90D BACK-UP RING

Ordered as VBU90031, this is an AS568-031 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 1.739 in (44.17 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 1.879 in (47.73 mm). The back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

Viton® (FKM) is specified here for outstanding high-temperature capability and very low compression set at elevated temperature. This material stands up to petroleum oils and fuels, engine and transmission fluids, and chlorinated solvents. Service temperature is rated from -15°F (-26.1°C) through 400°F (204.4°C). Verify compatibility before use with hot water and steam or low-molecular-weight organic acids.

It sees regular use in automotive fuel systems, chemical processing, and aerospace.

Stocked as VBU90031 and sold individually. Nominal inside diameter is listed as 1 3/4 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. Not finding the exact configuration you need? APG cross-references from prints, samples and competitor part numbers.