8-237 BLACK BUNA 90D BACK-UP RING

Buna-N Back-Up Ring, 3.359 in ID x 0.139 CS, 90A, Black, -40 to 250°F

Status
Available
Est. Ship Date
31 Oct 2026
Material
Buna-N (Nitrile / NBR)
Dash Size
237
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
3 3/8 inch
Nominal Outside Diameter
3 5/8 inch
Unit of Measure
EA
SKU:
HB90237
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Product Specification

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Part number HB90237 is an AS568-237 black Buna-N (Nitrile) 90 Shore A Back-Up Ring with an inside diameter of 3.359 in (85.32 mm), a cross section of 0.139 in (3.53 mm), and an outside diameter of 3.637 in (92.38 mm). A back-up ring extends o-ring service life by supporting the seal against extrusion under high pressure.

As a material, Buna-N (Nitrile) delivers low compression set under sustained load, reliable performance in both static and dynamic service. This material stands up to hydraulic fluids, many alcohols, and greases and lubricants. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Exposure to polar solvents or strong acids will shorten service life.

Common environments for this compound include fluid power, agricultural equipment, and construction equipment.

HB90237 ships individually. Unit weight is approximately 1.2596 g and nominal inside diameter is listed as 3 3/8 inch. Review your operating media and conditions against this specification before installation.
Item
HB90237
Description
8-237 BLACK BUNA 90D BACK-UP RING
Actual Cross Section
0.139 inch (3.53 mm)
Actual Inside Diameter
3.359 inch (85.32 mm)
Actual Outside Diameter
3.637 inch (92.38 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings