#4 AN Flare to 1/8in Pipe Steel

The #4 AN flare to 1/8in pipe steel adapter is a precision hydraulic fitting designed for marine fuel systems, engine cooling lines, and pressurized fluid transfer in boats and recreational watercraft. Built to military AN (Army-Navy) specifications, this straight adapter connects AN-4 flare male ports to 1/8-inch NPT (National Pipe Thread) male inlets, eliminating leaks and vibration-induced failures common in saltwater and high-vibration engine environments. Whether you're rebuilding a fuel manifold, upgrading fuel delivery plumbing, or retrofitting older marine engines with modern fuel systems, this adapter provides the secure, leak-free connection serious boaters demand.

Manufactured from steel with cadmium plating, the #4 AN flare to 1/8in pipe adapter resists corrosion from saltwater spray, fuel additives, and prolonged moisture exposure—critical for offshore and coastal applications. The AN flare end (SAE J518 Code 61) creates a mechanical seal that handles pressures up to 3,000 PSI without weeping, while the 1/8-inch NPT male threads accommodate standard marine manifolds, block ports, and fuel distribution blocks. The cadmium finish prevents galvanic corrosion when paired with aluminum or stainless steel components, ensuring reliability across multiple seasons of heavy use. At just 0.05 lbs, the compact form factor fits tight engine compartments without requiring additional brackets or spacers.

This adapter is essential for boaters transitioning from older NPT-only fuel and cooling systems to modern AN-based marine plumbing, or for anyone needing a single transition fitting in a hybrid system. Installation is straightforward: apply thread sealant (PTFE tape or anaerobic) to the NPT threads, hand-tighten, then secure with a wrench to prevent rotation. Compatible with fuel, coolant, and hydraulic fluid applications, the A-1 Products part A1PST81604 meets SAE J518 and AN standards for marine use. Keep a spare on hand for roadside repairs or mid-season system upgrades—this compact, high-pressure adapter has saved countless boaters from fuel system failures at sea.