8-254 BLACK BUNA 90D BACK-UP RING

Part number HB90254 is an AS568-254 black Buna-N (Nitrile) 90 Shore A Back-Up Ring with an inside diameter of 5.484 in (139.29 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 5.762 in (146.35 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

Buna-N (Nitrile) is specified here for strong abrasion and tear resistance, most widely specified general-purpose sealing elastomer. It resists water, propane and butane, and many alcohols. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. It is not the right choice where polar solvents or strong acids are present.

Maintenance and OEM teams specify it across hydraulic and pneumatic systems, agricultural equipment, and automotive.

Order part number HB90254, sold individually. Unit weight is approximately 2.0494 g. Review your operating media and conditions against this specification before installation. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.