8-219 BLACK BUNA 90D BACK-UP RING

This back-up ring is supplied in AS568-219 black Buna-N (Nitrile) 90 Shore A built to an inside diameter of 1.296 in (32.92 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 1.574 in (39.98 mm), catalogued under part number HB90219. It bridges the extrusion gap so the primary seal holds its shape under load.

As a material, Buna-N (Nitrile) delivers strong abrasion and tear resistance, reliable performance in both static and dynamic service. The compound resists water, greases and lubricants, and propane and butane. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Applications involving automotive brake fluid or ketones call for a different compound.

Typical settings include automotive, construction equipment, and agricultural equipment.

Reference part number HB90219 when ordering; the item is sold individually. Unit weight is approximately 0.503 g and nominal inside diameter is listed as 1 5/16 inch. Confirm chemical compatibility, pressure and temperature against your own application requirements before installing. 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.