Value Collection ZMSCHB90246 O-ring Backup Ring Nbr Dash 8-246

Product Description

The VALUE COLLECTION ZMSCHB90246 is a rectangular-cross-section backup O-ring made from Nitrile Butadiene Rubber (NBR), rated at 90 durometer for extra-hard hardness. It measures 4.506 inches inner diameter by 4.742 inches outer diameter, with a thickness of 0.0468 inches (approximately 3/64 inch). This backup ring is designed to prevent extrusion of primary O-rings under pressure and is used in hydraulic, pneumatic, and fluid-sealing assemblies. The NBR compound provides resistance to petroleum-based fluids, oils, and a wide service temperature range from -40 degrees F to 250 degrees F. Licensed plumbers, pipefitters, hydraulic technicians, and industrial maintenance professionals typically install this component.

This backup ring suits applications where a primary O-ring requires extrusion protection in grooved gland fittings, cylinders, and valve assemblies. The Dash 8-246 designation follows standard O-ring sizing conventions, making it a cross-reference-compatible selection for systems that specify this dash number. The extra-hard 90 durometer rating makes it well suited for higher-pressure circuits where softer backup rings would deform. It is sold in packages of 10 with a minimum order quantity of 1 package.

Key Features

• 90 durometer extra-hard NBR construction resists extrusion at elevated pressures
• Rectangular cross section provides full gland coverage as a backup ring
• Service temperature range of -40 degrees F to 250 degrees F
• Dash 8-246 standard sizing for straightforward cross-referencing
• NBR compound compatible with petroleum-based oils and hydraulic fluids
• Packaged in quantities of 10 per package

Compatibility

Designed as a standard Dash 8-246 backup ring for use with matching primary O-rings in hydraulic cylinders, pneumatic actuators, and fluid-sealing gland assemblies that require extrusion protection at this bore size.

Installation Notes

Backup rings are typically installed by hydraulic technicians, pipefitters, or maintenance mechanics working on pressurized fluid systems. Depressurize and isolate the system completely before disassembly and gland service. Inspect the gland groove for burrs or scoring before seating the backup ring, as surface defects accelerate seal wear. Do not stretch or twist the backup ring during installation; use a blunt probe if needed to seat it evenly in the groove.