AN6226-03 Buna-N 70 U-Cup Seal 1/4" ID X 5/8" OD X 3/16" CS

Get a dependable seal that installs easily and performs consistently under pressure. The AN6226-03 U-Cup Seal is designed to prevent leaks, reduce downtime, and keep your hydraulic and pneumatic systems running smoothly.

Made from black Buna-N (NBR) at 70 durometer, this seal delivers excellent oil resistance and flexibility. It is a strong, cost-effective choice for customers who need reliable sealing performance in small to mid-size applications.

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

Material & Performance Details

This U-Cup is manufactured from Buna-N (Nitrile, NBR), a trusted material across fluid power industries. The 70 durometer hardness provides the right balance between flexibility for sealing and strength for durability.

U-Cups seal efficiently without heavy initial compression, making them ideal for low breakaway pressure and smooth operation.

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 weather exposure

Not compatible with:

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

Sizes & Measurements

• Cross Section (CS): 3/16" (0.187" | 4.75 mm)
• Inside Diameter (ID): 1/4" (0.250" | 6.35 mm)
• Outside Diameter (OD): 5/8" (0.625" | 15.88 mm)
• Part Number: AN6226-03
• Cross References:
  • Parker Hannifin: 42956226-03
  • Hercules: 870-03
  • Martin Fluid Power: 6226-03
  • Precision Associates: 6226-3

Dimensions: 1/4" ID X 5/8" OD X 3/16" CS
Actual: 0.250" ID X 0.625" OD X 0.187" CS
Metric: 6.35 mm ID X 15.88 mm OD X 4.75 mm CS

Applications & Use Cases

This AN6226 Series U-Cup is widely used in hydraulic cylinders, pneumatic systems, pumps, and valves. It is ideal for applications requiring reliable sealing with low friction and consistent performance.

With a pressure rating up to 500 PSI, it is well suited for both OEM equipment and maintenance repair work.

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 reliability, speed, and support that helps you avoid costly delays.

• 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
• Experienced technical support
• Competitive pricing without sacrificing quality

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

FAQs

1. What does AN6226 mean?
AN6226 is an Army-Navy specification that standardizes U-Cup seal sizes and performance.

2. Is this seal good for hydraulic oil?
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.