AN6226-38 Buna-N 70 U-Cup Seal 2-3/4" ID X 3-1/2" OD X 3/8" CS

Get a heavy-duty seal built for larger bore systems where strength and reliability are critical. The AN6226-38 U-Cup Seal delivers consistent sealing performance, helping prevent leaks, reduce downtime, and keep your hydraulic and pneumatic systems running efficiently.

Manufactured from black Buna-N (NBR) at 70 durometer, this U-Cup provides excellent oil resistance and durability. The larger 3/8" square profile increases sealing strength and stability, making it ideal for demanding fluid power applications.

Operating temperature: -40° to +225°F (–40° to +107°C)

Material & Performance Details

This seal is made from Buna-N (Nitrile, NBR), one of the most widely used sealing materials in fluid power systems. The 70 durometer hardness provides a strong balance between flexibility and long service life.

The AN6226 design features a square-style cross section where the nominal cross section equals the height. The increased 3/8" cross section provides enhanced durability and consistent sealing performance under load.

Excellent resistance to:

• Petroleum-based oils and fuels
• Hydraulic fluids
• Mineral oils and greases
• Water (short-term exposure)

Limited capability with:

• Mild acids and bases
• Ozone and outdoor exposure

Not compatible with:

• Strong acids
• Brake fluids (glycol-based)
• Aromatic hydrocarbons

Sizes & Measurements

• Cross Section (CS): 3/8" (0.375" | 9.53 mm)
• Inside Diameter (ID): 2-3/4" (2.750" | 69.85 mm)
• Outside Diameter (OD): 3-1/2" (3.500" | 88.90 mm)
• Part Number: AN6226-38
• Cross References:
  • Parker Hannifin: 42956226-38
  • Hercules: 870-38
  • Martin Fluid Power: 6226-38
  • Precision Associates: 6226-38

Dimensions: 2-3/4" ID X 3-1/2" OD X 3/8" CS
Actual: 2.750" ID X 3.500" OD X 0.375" CS
Metric: 69.85 mm ID X 88.90 mm OD X 9.53 mm CS

Applications & Use Cases

This AN6226 Series U-Cup is commonly used in hydraulic cylinders, pneumatic systems, pumps, and valves where larger diameters and increased sealing strength are required. The larger 3/8" cross section makes it well suited for applications with higher wear, wider tolerances, or heavier loads.

With a pressure rating up to 500 PSI, it is a dependable solution for both OEM equipment and maintenance applications.

Key Specifications

• Material: Buna-N (NBR)
• Durometer: 70 Shore A
• Color: Black
• Specification: AN6226 (Army-Navy Standard)
• Temperature Range: -40°F to +225°F (-40°C to +107°C)
• Pressure Rating: Up to 500 PSI

Why Buy from The O-Ring Store LLC

When you order from us, you are getting more than just a seal. You are getting accuracy, speed, and support that helps you avoid downtime and rework.

• ISO9001:2015 certified quality processes
• USA stock for fast delivery
• Same-day shipping on in-stock items
• Custom sizes available when standard sizes do not fit
• Full lot traceability and documentation available
• Technical support from experienced staff
• Competitive pricing without sacrificing quality

We focus on helping you get the right seal the first time so your equipment keeps running.

FAQs

1. What is the advantage of the 3/8" cross section?
The larger cross section provides increased sealing strength, durability, and stability in high-load or wide-clearance applications.

2. Is Buna-N suitable for hydraulic systems?
Yes. Buna-N offers excellent resistance to petroleum-based oils and hydraulic fluids.

3. What pressure can this seal handle?
This U-Cup is rated for applications up to 500 PSI.