8-316 BLACK FKM 90D BACK-UP RING

Part number VBU90316 is an AS568-316 black Viton® (FKM) 90 Shore A Back-Up Ring measuring an inside diameter of 0.85 in (21.59 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 1.27 in (32.26 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

The material holds up against engine and transmission fluids, aromatic hydrocarbons, and petroleum oils and fuels. That behavior comes from the compound itself: Viton® (FKM) is known for outstanding high-temperature capability and very low compression set at elevated temperature. Published continuous service range is -15°F (-26.1°C) to 400°F (204.4°C). Exposure to amines or low-molecular-weight organic acids will shorten service life.

Common environments for this compound include aerospace, semiconductor equipment, and high-temperature process equipment.

VBU90316 ships individually. Nominal inside diameter is listed as 7/8 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. For a size or compound outside the standard catalog, APG can quote from a print or sample.