Value Collection ZMSCHB90333 O-ring Backup Ring Nbr

Product Description

The VALUE COLLECTION ZMSCHB90333 is a rectangular cross-section backup ring O-ring made from Nitrile Butadiene Rubber (NBR), used to prevent extrusion and maintain seal integrity in high-pressure fluid and pneumatic systems. It measures 2.518 inches inner diameter by 2.884 inches outer diameter with a 0.0625-inch thickness and carries a 90 durometer hardness rating, placing it in the extra-hard range. The ring is rated for service from -40 degrees F to 250 degrees F, making it suitable for a wide range of hydraulic, pneumatic, and fluid-handling applications. Licensed plumbers, hydraulic technicians, and industrial maintenance professionals typically install this type of seal during assembly or scheduled maintenance.

This backup ring is used in residential and commercial plumbing, hydraulic cylinders, pneumatic actuators, and fluid-power systems where standard O-rings require anti-extrusion support. The Dash 8-333 designation identifies its standardized sizing within the AS568 O-ring numbering system, allowing cross-referencing with other manufacturers and OEM service documentation. It is well-suited for sealing applications involving petroleum-based fluids, water, and many common hydraulic oils where NBR compounds perform reliably within the rated temperature range.

Key Features

• Rectangular cross-section profile designed as a backup ring to prevent O-ring extrusion under pressure
• 90 durometer extra-hard NBR construction for resistance to deformation in demanding service conditions
• Temperature-rated from -40 degrees F to 250 degrees F for broad application coverage
• Dash 8-333 standard sizing for straightforward cross-reference and replacement identification
• Sold in packages of 10 with a minimum order quantity of 1

Compatibility

Designed as a standard Dash 8-333 backup ring for use in hydraulic, pneumatic, and fluid-sealing applications requiring a 2.518-inch ID rectangular-profile seal in NBR material. Not FDA approved.

Installation Notes

Installation is typically performed by licensed plumbers, hydraulic technicians, or industrial maintenance mechanics. De-energize or depressurize the system fully before disassembling any seal cavity. Inspect the groove and mating surfaces for burrs or damage before seating the ring. Avoid twisting or rolling the ring during installation; a light application of compatible fluid or assembly lubricant eases placement without compromising the seal.