#12 Union Fitting

The #12 Union Fitting from FRAGOLA is a precision hydraulic adapter engineered for custom fuel system, brake line, and cooling circuit fabrication in high-performance automotive builds. Whether you're assembling a race-spec fuel system, retrofitting braided stainless steel lines into a classic restoration, or designing a custom cooling loop for a modified engine, this fitting serves as a critical junction point that allows two male-threaded hoses or hard lines to connect without welding. Union fittings eliminate the need for separate bulkhead adapters and reduce assembly complexity while maintaining leak-free integrity under pressure and vibration.

Manufactured by FRAGOLA, a trusted name in motorsports fluid systems, this #12 union fitting is precision-machined from aluminum or steel with a swaged ferrule design that creates a mechanical seal when torqued. The #12 designation refers to a -12 AN (Army-Navy) thread size, the industry standard for high-flow applications where vibration resistance and durability are non-negotiable. The compact 1.95 x 1.55 x 4-inch profile fits tight engine bays and custom chassis without adding bulk, while the lightweight 0.13-pound construction minimizes parasitic weight in performance-critical builds. FRAGOLA fittings meet SAE J518 standards and withstand sustained pressure cycles without creep or thread stripping—critical attributes in drag racing, road racing, and turbo applications.

Mechanics and fabricators building custom fuel systems for carbureted or EFI engines, turbo installations, and vintage car restorations rely on FRAGOLA union fittings to simplify line routing and reduce connection points. The #12 size is ideal for main fuel feed lines, coolant bypass loops, and brake system modifications where flow capacity and pressure rating (typically 300+ PSI depending on application) matter. When installing, ensure both mating ports are -12 AN threaded and use a backup wrench to prevent line damage during final torque; this fitting integrates seamlessly with any FRAGOLA component or compatible -12 AN hard line and hose assemblies.