Value Collection ZMSCH70438 O-ring Dash 438 Nbr 70

Product Description

The VALUE COLLECTION ZMSCH70438 is a Dash 438 O-ring manufactured from Nitrile Butadiene Rubber (NBR), also known as Buna-N, one of the most widely used elastomers in fluid sealing applications. It features a round cross-section measuring 6.25 inches inside diameter, 6.75 inches outside diameter, and 0.25 inches thick. Rated at 70 durometer hardness, this O-ring provides reliable compression set resistance along with strong tear and abrasion resistance. It is suited for sealing applications involving petroleum-based fluids and operates across a temperature range of -40 degrees F to 250 degrees F. HVAC technicians, plumbers, and maintenance professionals commonly specify NBR O-rings for hydraulic, pneumatic, and fluid system sealing.

This O-ring is appropriate for use in residential and commercial systems where petroleum product compatibility is required. Typical applications include pump housings, valve bodies, pipe flanges, and hydraulic fittings where a large-diameter static or dynamic face seal is needed. The Dash 438 designation follows standard sizing conventions, making it a straightforward drop-in specification match when replacing worn or damaged seals in existing assemblies. Each package contains 2 O-rings. NBR material should not be stored in direct sunlight or near motors and other electrical equipment that may generate ozone, as ozone exposure degrades the elastomer.

Key Features

• Nitrile Butadiene Rubber (Buna-N) construction with excellent resistance to petroleum products
• 70 durometer hardness rating for reliable compression set and sealing force
• Operates from -40 degrees F to 250 degrees F
• Round cross-section geometry per standard Dash 438 sizing
• Strong tear and abrasion resistance for demanding sealing environments
• Meets SAE and MIL-Spec standards

Compatibility

Designed as an OEM-style replacement O-ring for applications requiring a Dash 438 NBR seal compatible with petroleum products, hydraulic fluids, and similar media in plumbing, HVAC, and industrial fluid systems.

Installation Notes

Installation should be performed by a qualified technician familiar with the specific system being serviced. Depressurize and drain the system before removing the existing O-ring, and inspect the groove and mating surfaces for damage or contamination before fitting the new seal. Apply a compatible lubricant to the O-ring prior to installation to ease seating and reduce the risk of tearing. Avoid rolling or twisting the O-ring during installation to ensure proper seating and long-term sealing integrity.