8-433 BLACK BUNA 90D BACK-UP RING

Buna-N Back-Up Ring, 5.475 in ID x 0.275 CS, 90A, Black, -40 to 250°F

Status
Available
Est. Ship Date
1 Nov 2026
Material
Buna-N (Nitrile / NBR)
Dash Size
433
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
1/4 inch
Nominal Inside Diameter
5 1/2 inch
Nominal Outside Diameter
6 inch
Unit of Measure
EA
SKU:
HB90433
Please login to see price and add to cart

Product Specification

-
Part number HB90433 is an AS568-433 black Buna-N (Nitrile) 90 Shore A Back-Up Ring supplied with an inside diameter of 5.475 in (139.07 mm), a cross section of 0.275 in (6.99 mm), and an outside diameter of 6.025 in (153.04 mm). A back-up ring bridges the extrusion gap so the primary seal holds its shape under load.

Buna-N (Nitrile) is widely chosen for the most widely specified general-purpose sealing elastomer and an economical choice for high-volume maintenance programs. The compound resists water, hydraulic fluids, and many alcohols. Rated temperature range runs from -40°F (-40°C) to 250°F (121.1°C) in continuous service. Verify compatibility before use with ozone and direct sunlight or automotive brake fluid.

Typical settings include agricultural equipment, construction equipment, and fluid power.

Order part number HB90433, sold individually. Unit weight is approximately 10.0089 g and nominal inside diameter is listed as 5 1/2 inch. Application requirements vary, so validate compatibility with your process conditions prior to installation. For a size or compound outside the standard catalog, APG can quote from a print or sample.
Item
HB90433
Description
8-433 BLACK BUNA 90D BACK-UP RING
Actual Cross Section
0.275 inch (6.99 mm)
Actual Inside Diameter
5.475 inch (139.07 mm)
Actual Outside Diameter
6.025 inch (153.04 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings