AN6226-26 U-Cup Seal Buna-N NBR 70 1-3/8" ID X 2" OD X 5/16" CS

Built from black Buna-N rubber, this U-Cup is ideal for customers who need strong oil resistance, consistent sealing under pressure, and a cost-effective solution that performs day in and day out.

When you need a reliable seal that keeps your equipment running without leaks, the AN6226-26 U-Cup Seal delivers. Designed for hydraulic and pneumatic systems, this 70 durometer Buna-N (NBR) seal provides dependable sealing performance, reduces downtime, and helps protect your equipment from costly failures.

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

Material & Performance Details

This seal is made from Buna-N (Nitrile, NBR) with a 70 durometer hardness, offering a strong balance of flexibility and durability. It performs well in dynamic sealing applications where oil resistance and wear resistance are critical.

Buna-N is one of the most widely used sealing materials due to its reliability and cost efficiency.

Excellent resistance to:

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

Limited capability with:

• Mild acids and bases
• Outdoor weathering and ozone exposure

Not compatible with:

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

Sizes & Measurements

• Dimensions: 1-3/8" ID X 2" OD X 5/16" CS
• Actual: 1.375" ID X 2.000" OD X 0.312" CS
• Metric: 34.93 mm ID X 50.80 mm OD X 7.95 mm CS
• Part Number: AN6226-26
• Cross References:
  • Parker Hannifin: 42956226-26
  • Hercules: 870-26
  • Martin Fluid Power: 6226-26
  • Precision Associates: 6226-26

Applications & Use Cases

These AN6226 Series U-Cups are built for real-world use in hydraulic cylinders, pneumatic systems, pumps, and valves. You will commonly find them in mobile equipment, industrial machinery, and fluid power systems where dependable sealing is required under moderate pressure.

With a pressure rating up to 500 PSI, this seal is a solid choice for applications that demand consistent sealing without overcomplicating the design.

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 not just getting a seal. You are getting a system that makes your job easier and more predictable.

We focus on getting it right the first time so you are not dealing with returns, downtime, or guesswork.

• ISO9001:2015 certified processes ensure consistency and quality
• USA-based inventory for fast, reliable delivery
• Same-day shipping on in-stock items
• Custom sizes and materials available when standard does not fit
• Full lot traceability and documentation available
• Real technical support from people who understand seals
• Competitive pricing without cutting corners

We make getting O-Rings easy, and that includes U-Cup seals like this one.

FAQs

1. What does AN6226 mean?
AN6226 is an Army-Navy specification that defines the dimensions and performance standards for U-Cup seals, ensuring consistency across manufacturers.

2. Can this seal handle hydraulic oil?
Yes. Buna-N is highly resistant to petroleum-based oils and hydraulic fluids, making it ideal for hydraulic systems.

3. What pressure can this U-Cup handle?
This seal is rated for applications up to 500 PSI, making it suitable for many standard hydraulic and pneumatic systems.