Value Collection ZMSCH70343 O-ring Dash 343 Buna-n 70A

Product Description

The VALUE COLLECTION ZMSCH70343 is a Dash 343 O-ring made from Nitrile Butadiene Rubber (Buna-N), the most widely used elastomer in industrial and fluid-system sealing applications. It measures 3.75 inches inner diameter by 4.125 inches outer diameter with a 0.1875-inch (3/16-inch) cross section thickness. The round cross section profile seats consistently in standard O-ring grooves. At a 70 Shore A hardness rating, this ring delivers a firm seal with strong resistance to compression set, tearing, and abrasion. It is suitable for use with petroleum-based fluids and is installed by plumbers, HVAC technicians, and fluid-system mechanics across a wide range of applications.

This O-ring is used wherever a Dash 343 dimension is specified in hydraulic, pneumatic, fuel, or lubrication systems. Typical applications include pump housings, valve bodies, cylinder heads, and fluid-line fittings that contact petroleum products. The Buna-N compound performs reliably across a temperature range of -40 degrees F to 250 degrees F, making it appropriate for both refrigeration-adjacent mechanical assemblies and standard plumbing or hydraulic circuits. Each package contains 25 rings, suitable for stocking at a service facility or completing a multi-unit repair job.

Key Features

• Buna-N (Nitrile Butadiene Rubber) compound — excellent resistance to petroleum products, oils, and fuels
• 70 Shore A hardness — firm seal with good compression set resistance
• Round cross section — fits standard Dash 343 O-ring grooves without modification
• Operating temperature range: -40 degrees F to 250 degrees F
• Tear and abrasion resistant — suitable for dynamic and static sealing applications
• Meets SAE and MIL-Spec standards
• Package quantity of 25 rings per order unit

Compatibility

Designed as a direct-dimension replacement for any application specifying a Dash 343 O-ring in Buna-N. Compatible with systems and fluids classified as petroleum products. Not recommended for use with ozone-generating equipment, direct sunlight exposure, or non-petroleum fluid systems without verifying elastomer compatibility.

Installation Notes

Power down or depressurize the system fully before replacing O-rings in any hydraulic, pneumatic, or fluid-carrying assembly. Inspect the groove for nicks, burrs, or debris before seating the new ring. Lightly lubricate the O-ring with a compatible petroleum-based lubricant to aid installation and prevent pinching or tearing. Do not store unused rings near motors, electrical equipment, or in direct sunlight, as ozone and UV exposure degrade Buna-N over time.