Value Collection ZMSCHB90028 O-ring Backup Ring Nbr 90 Duro

Product Description

The VALUE COLLECTION ZMSCHB90028 is a Dash 8-028 rectangular cross-section backup O-ring made from Nitrile Butadiene Rubber (NBR). It measures 1.393 inches inside diameter, 1.5 inches outside diameter, and 0.0468 inches thick. Rated at 90 durometer, this extra-hard ring is designed to prevent O-ring extrusion under pressure in hydraulic, pneumatic, and fluid-handling systems. It handles a working temperature range of -40 degrees F to 250 degrees F. Plumbers, hydraulic technicians, and mechanical tradespeople install this type of backup ring alongside primary O-rings to extend seal life in high-pressure applications.

This backup ring is suited for use in residential and commercial fluid-handling assemblies, hydraulic cylinders, pneumatic actuators, and pump fittings where standard O-rings require anti-extrusion support. The rectangular cross section seats against the low-pressure side of a primary O-ring groove, preventing the primary seal from being pushed into the clearance gap under load. It is commonly installed in systems subject to pressure spikes or continuous high-pressure service. Sold in a package quantity of 50 units, this part is appropriate for shop stock or job-lot replenishment.

Key Features

• Nitrile Butadiene Rubber (NBR) construction resists petroleum-based fluids, oils, and fuels
• 90 durometer extra-hard rating provides strong extrusion resistance at elevated pressures
• Rectangular cross section functions as a backup ring seated on the low-pressure side of a primary O-ring
• Operating range of -40 degrees F to 250 degrees F suits a wide range of service environments
• Dash 8-028 sizing conforms to standard O-ring groove specifications for consistent fitment
• Package quantity of 50 units supports bench stock and multi-seal repair jobs

Compatibility

Designed as an OEM-style replacement backup ring for hydraulic, pneumatic, and fluid-handling assemblies using Dash 8-028 standard groove dimensions with a 1.393-inch inside diameter and 1.5-inch outside diameter.

Installation Notes

Installation is performed by licensed plumbers, hydraulic technicians, or qualified mechanical trades personnel. Depressurize and isolate the system completely before disassembling any sealed joint or cylinder. Seat the backup ring on the low-pressure side of the O-ring groove, ensuring the primary O-ring is installed correctly against it with no twisting or pinching. Inspect the groove and mating surfaces for scoring or contamination before reassembly.