AN6226-45 Buna-N 70 U-Cup Seal 3/8" ID X 5/8" OD X 1/8" CS

Get a compact, reliable seal that performs in tight spaces without sacrificing durability. The AN6226-45 U-Cup Seal is designed to prevent leaks, reduce downtime, and keep your hydraulic and pneumatic systems running smoothly.

Manufactured from black Buna-N (NBR) at 70 durometer, this U-Cup offers excellent oil resistance and flexibility. The smaller 1/8" square profile makes it ideal for precision applications where space is limited but consistent sealing is required.

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

Material & Performance Details

This seal is made from Buna-N (Nitrile, NBR), a widely trusted sealing material in fluid power systems. The 70 durometer hardness provides a strong balance between flexibility and durability.

The AN6226 design features a square-style cross section where the nominal cross section equals the height, ensuring stable sealing performance in compact applications.

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): 1/8" (0.125" | 3.18 mm)
• Inside Diameter (ID): 3/8" (0.375" | 9.53 mm)
• Outside Diameter (OD): 5/8" (0.625" | 15.88 mm)
• Part Number: AN6226-45
• Cross References:
  • Parker Hannifin: 42956226-45
  • Hercules: 870-45
  • Martin Fluid Power: 6226-45
  • Precision Associates: 6226-45

Dimensions: 3/8" ID X 5/8" OD X 1/8" CS
Actual: 0.375" ID X 0.625" OD X 0.125" CS
Metric: 9.53 mm ID X 15.88 mm OD X 3.18 mm CS

Applications & Use Cases

This AN6226 Series U-Cup is commonly used in small hydraulic cylinders, pneumatic systems, valves, and compact fluid control applications. It is ideal where low friction, precision fit, and consistent sealing are required.

With a pressure rating up to 500 PSI, it is a dependable option 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 mistakes and downtime.

• 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 make getting O-Rings easy and help you get it right the first time.

FAQs

1. What makes this size ideal for compact applications?
The 1/8" cross section allows it to fit tight spaces while still delivering reliable sealing performance.

2. Is Buna-N suitable for oil applications?
Yes. Buna-N provides 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.