8-284 BLACK BUNA 90D BACK-UP RING

Buna-N Back-Up Ring, 17.955 in ID x 0.139 CS, 90A, Black, -40 to 250°F

Status
Out of Stock
Est. Ship Date
29 Oct 2026
Material
Buna-N (Nitrile / NBR)
Dash Size
284
Durometer
90 Shore A
Cross Section Type
Round
Color
Black
Minimum Temperature
-40°F (-40°C)
Maximum Temperature
250°F (121°C)
Nominal Cross Section
1/8 inch
Nominal Inside Diameter
18 inch
Nominal Outside Diameter
18 1/4 inch
Unit of Measure
EA
SKU:
HB90284

Product Specification

-
Part number HB90284 is an AS568-284 black Buna-N (Nitrile) 90 Shore A Back-Up Ring built to an inside diameter of 17.955 in (456.06 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 18.233 in (463.12 mm). A back-up ring allows a standard o-ring to operate at higher pressures than it could unsupported.

Expect good resistance to water, propane and butane, and hydraulic fluids. Buna-N (Nitrile) is specified for the most widely specified general-purpose sealing elastomer and low compression set under sustained load. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Verify compatibility before use with ketones or automotive brake fluid.

Typical settings include construction equipment, agricultural equipment, and general industrial maintenance.

HB90284 ships individually. Unit weight is approximately 6.8741 g and nominal inside diameter is listed as 18 inch. Review your operating media and conditions against this specification before installation.
Item
HB90284
Description
8-284 BLACK BUNA 90D BACK-UP RING
Actual Cross Section
0.139 inch (3.53 mm)
Actual Inside Diameter
17.955 inch (456.06 mm)
Actual Outside Diameter
18.233 inch (463.12 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings