8-336 BLACK FKM 90D BACK-UP RING

Viton® Back-Up Ring, 2.85 in ID x 0.21 CS, 90A, Black, -15 to 400°F

Status
Available
Est. Ship Date
31 Oct 2026
Material
Fluoroelastomer (FKM/Viton)
Dash Size
336
Durometer
90 Shore A
Cross Section Type
Round
Color
Black
Minimum Temperature
-15°F (-26°C)
Maximum Temperature
400°F (204°C)
Nominal Cross Section
3/16 inch
Nominal Inside Diameter
2 7/8 inch
Nominal Outside Diameter
3 1/4 inch
Unit of Measure
EA
SKU:
VBU90336
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Product Specification

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The VBU90336 is an AS568-336 black Viton® (FKM) 90 Shore A Back-Up Ring with an inside diameter of 2.85 in (72.39 mm), a cross section of 0.21 in (5.33 mm), and an outside diameter of 3.27 in (83.06 mm). This back-up ring installs on the low-pressure side of an o-ring to prevent extrusion into the clearance gap at elevated pressure.

This material stands up to aggressive chemicals, chlorinated solvents, and many acids. Viton® (FKM) offers the industry benchmark where nitrile reaches its thermal limit and very low compression set at elevated temperature. The material carries a published service range of -15°F (-26.1°C) to 400°F (204.4°C). Verify compatibility before use with amines or ketones and esters.

Common environments for this compound include automotive fuel systems, chemical processing, and aerospace.

VBU90336 ships individually. Unit weight is approximately 3.3576 g and nominal inside diameter is listed as 2 7/8 inch. As always, verify media compatibility and operating conditions against the requirements of your specific application. 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.
Item
VBU90336
Description
8-336 BLACK FKM 90D BACK-UP RING
Actual Cross Section
0.21 inch (5.33 mm)
Actual Inside Diameter
2.85 inch (72.39 mm)
Actual Outside Diameter
3.27 inch (83.06 mm)
FDA Compliant
No
Measurement System
Imperial
Metal Detectable
No
NSF Certified
No
Product Code
6002
Product Category
O-Rings - Backup Rings