8-426 BLACK FKM 90D BACK-UP RING

This back-up ring is supplied in AS568-426 black Viton® (FKM) 90 Shore A supplied with an inside diameter of 4.6 in (116.84 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 5.15 in (130.81 mm), catalogued under part number VBU90426. It extends o-ring service life by supporting the seal against extrusion under high pressure.

The compound resists aggressive chemicals, chlorinated solvents, and engine and transmission fluids. That behavior comes from the compound itself: Viton® (FKM) is known for excellent resistance to compression set and permeation, long service life in hot, chemically aggressive environments. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C).

Maintenance and OEM teams specify it across automotive fuel systems, aerospace, and high-temperature process equipment.

VBU90426 ships individually. Unit weight is approximately 11.249 g. Review your operating media and conditions against this specification before installation. If you need a size, durometer or compound that is not listed, APG can cross-reference from a print, a sample or a competitor part number.