Taiidaues 6AN Flare Cap Block-Off Fittings, 6 Pcs Black Aluminum Hex Adapters 6061‑T6 37° Seal

These Taiidaues 6AN flare cap block-off fittings are aluminum 6AN female hex adapters designed to securely seal AN flare lines and block off unused ports in fuel, oil, and hydraulic systems.

Precision-machined from 6061-T6 aluminum, this six-piece set delivers lightweight strength and corrosion resistance for automotive, racing, and industrial plumbing tasks. Each cap features a 37° conical sealing surface and 9/16"-18 UNF AN threading to match standard 6AN flare male fittings, creating a tight, high-pressure seal. The black anodized finish protects the surface while providing a professional appearance on engine bays, fuel systems, and custom hose assemblies.

How do these caps create a leak-resistant connection?

The design uses a 37° conical sealing face that mates precisely with AN male flare fittings, forming a metal-to-metal seal. Combined with accurate 9/16"-18 UNF threading, the caps clamp down evenly, minimizing gaps where fluid or vapor could escape.

• 37° conical sealing surface compatible with 6AN flare fittings
• Precision 9/16"-18 UNF AN thread for proper engagement
• Hex adapter shape allows even torque application for consistent seals

What operating conditions and pressures can these adapters handle?

Manufactured from 6061-T6 aluminum and anodized for surface protection, the caps tolerate a wide temperature range and resist corrosion in demanding environments. They are rated for working pressures up to about 1500 psi under typical conditions, making them suitable for many fuel and low- to mid-pressure hydraulic applications.

• Working pressure rating around 1500 psi for standard use
• Temperature range roughly -65°F to 252°F (-54°C to 122°C)
• 6061-T6 alloy offers high strength with reduced weight

Which systems and applications are these 6AN caps best suited for?

These block-off fittings are intended to close unused AN ports or temporarily cap lines during maintenance and assembly. They are commonly used in returnless fuel systems, fuel cells, fuel lines, valve covers, and other automotive or custom plumbing setups where contamination prevention and secure shutdowns are required.

• Returnless fuel systems and fuel cell installations
• Fuel, oil, and low- to mid-pressure hydraulic lines
• Service or assembly uses: block-offs, test caps, and temporary seals

How do I install and remove these flare cap adapters safely?

Installation is straightforward: hand-start the cap onto the male AN flare, then tighten with a wrench on the hex to achieve a snug metal-to-metal seal. For removal, loosen the hex with a wrench and back the cap off by hand; always depressurize the line and follow safety procedures before working on fluid systems.

• Hand-thread first to avoid cross-threading
• Use a wrench on the hex for final tightening — avoid over-torquing
• Always depressurize and drain lines before removal

Who is this for: mechanics, fabricators, and DIY enthusiasts who need reliable 6AN caps for blocking or sealing AN flare fittings will find these Taiidaues adapters practical and cost-effective. The six-piece pack suits small projects, shop spares, or vehicle maintenance tasks where consistent sealing, corrosion resistance, and lightweight performance matter.