Value Collection ZMSCH70338 O-ring Dash 338 Nbr 70 Duro

Product Description

The VALUE COLLECTION ZMSCH70338 is a Dash 338 O-ring in Buna-N (Nitrile Butadiene Rubber) with a round cross section, designed for static and dynamic sealing applications across plumbing, HVAC, hydraulic, and fluid-handling systems. It measures 3.125 inches inside diameter, 3.500 inches outside diameter, and 0.1875 inches thick. The compound carries a Shore A hardness of 70, placing it in the hard rating category. Rated for service from -40 degrees F to 250 degrees F, this O-ring is well suited to petroleum-based fluids and is the industry standard elastomer choice for general-purpose sealing in trade and industrial environments.

This O-ring is appropriate for residential and commercial applications wherever a Dash 338 profile is required. Common install scenarios include pump housings, valve bodies, pipe fittings, and hydraulic cylinder end caps that contact petroleum products, oils, fuels, and hydraulic fluids. Each package contains 25 rings. Buna-N is recognized as the most widely used O-ring elastomer in the HVAC, plumbing, and fluid-power trades and is the default specification for many OEM and MRO applications. It should not be stored in direct sunlight or near motors or electrical equipment that may generate ozone, as ozone degrades NBR compound over time.

Key Features

• Buna-N (NBR) elastomer with excellent resistance to petroleum products, oils, and fuels
• Shore A 70 hardness for reliable compression set and tear and abrasion resistance
• Operating temperature range of -40 degrees F to 250 degrees F
• Round cross section per Dash 338 standard: 3.125 inches ID, 3.500 inches OD, 0.1875 inches thick
• Conforms to SAE and MIL-Spec standards
• Sold in a convenient 25-piece package with a minimum order quantity of 1

Compatibility

Compatible with petroleum products, oils, fuels, and hydraulic fluids. Designed as a standard Dash 338 replacement O-ring for any application specifying a 3.125 inches ID, 3.500 inches OD, 0.1875 inches thick round-cross-section Buna-N seal. Not FDA approved; not recommended for food-contact or strong-acid service.

Installation Notes

Licensed plumbers, HVAC technicians, and hydraulic service technicians typically install O-rings of this type. Always depressurize and de-energize the system and drain any residual fluid before removing the old seal. Inspect the groove and mating surfaces for scoring or corrosion before seating the new ring. Lightly lubricate the O-ring with a compatible grease or fluid prior to installation to prevent rolling and tearing during assembly.