8-353 BLACK BUNA 90D BACK-UP RING

Part number HB90353 is an AS568-353 black Buna-N (Nitrile) 90 Shore A Back-Up Ring measuring an inside diameter of 4.975 in (126.37 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 5.395 in (137.03 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 economical choice for high-volume maintenance programs and most widely specified general-purpose sealing elastomer. Expect good resistance to water, propane and butane, and greases and lubricants. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. It should not be specified for service in ketones or automotive brake fluid.

You will find this material specified across automotive, fluid power, and agricultural equipment.

Order part number HB90353, sold individually. Unit weight is approximately 4.2953 g and nominal inside diameter is listed as 5 inch. Review your operating media and conditions against this specification before installation. APG can cross-reference from an existing part number, a drawing or a physical sample if this size is not an exact match.