Value Collection ZMSCHB90325 Nbr O-ring Backup Ring 90D

Product Description

The VALUE COLLECTION ZMSCHB90325 is a rectangular cross-section backup ring designed to prevent O-ring extrusion in high-pressure sealing applications. Made from Nitrile Butadiene Rubber (NBR) with a 90 durometer hardness rating, this part provides an extra-hard barrier that supports the primary O-ring under dynamic or static load. Key dimensions are 1.513 inches inner diameter, 1.879 inches outer diameter, and 0.0625 inches thickness. The operating temperature range runs from -40 degrees F to 250 degrees F, making it suitable for fluid and pneumatic systems that see wide thermal cycling. Plumbers, hydraulic technicians, and mechanical contractors are the primary installers.

This backup ring is used in groove-seated sealing assemblies where standard round O-rings require additional support against extrusion through the clearance gap. Typical applications include hydraulic cylinders, pneumatic actuators, fluid control valves, and pump assemblies found in industrial, HVAC, and plumbing systems. The NBR compound resists petroleum-based oils, fuels, and water, which are common media in these environments. Each package contains 25 pieces, and the minimum order quantity is 1 package.

Key Features

• Rectangular cross-section prevents O-ring extrusion under pressure differential
• 90 durometer extra-hard NBR material for high-load sealing support
• Operating range of -40 degrees F to 250 degrees F suits thermally demanding systems
• Dash 8-325 designation allows direct cross-reference to standard sizing charts
• NBR compound compatible with petroleum oils, fuels, water, and many hydraulic fluids
• Packaged in quantities of 25 for bench-stock and service van stocking

Compatibility

Designed as a standard Dash 8-325 backup ring for use alongside O-rings in rectangular-groove sealing assemblies across hydraulic, pneumatic, and fluid-handling equipment requiring extra-hard NBR sealing support.

Installation Notes

Installation is typically performed by licensed plumbers, hydraulic technicians, or mechanical contractors. Depressurize and de-energize the system fully before disassembling any sealing joint. Inspect the groove dimensions and clearance gap to confirm the backup ring seats flush without pinching or twisting. Avoid using sharp tools that can nick the rubber surface during installation, as surface damage reduces sealing effectiveness.