8-033 BLACK BUNA 90D BACK-UP RING

This back-up ring is supplied in AS568-033 black Buna-N (Nitrile) 90 Shore A with an inside diameter of 1.989 in (50.52 mm), a cross section of 0.07 in (1.78 mm), and an outside diameter of 2.129 in (54.08 mm), catalogued under part number HB90033. It extends o-ring service life by supporting the seal against extrusion under high pressure.

The material holds up against many alcohols, petroleum-based oils, and hydraulic fluids. That behavior comes from the compound itself: Buna-N (Nitrile) is specified for the most widely specified general-purpose sealing elastomer and an economical choice for high-volume maintenance programs. Continuous operating temperature is published at -40°F (-40°C) to 250°F (121.1°C). Exposure to ketones or automotive brake fluid will shorten service life.

Maintenance and OEM teams specify it across agricultural equipment, fluid power, and automotive.

HB90033 ships individually. Unit weight is approximately 0.3515 g and nominal inside diameter is listed as 2 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. APG supports cross-referencing from drawings, samples and competitor numbers when a listed size is not an exact fit.