Brake Adapter Fitting #4 to 3/8-24 IF Male

The Brake Adapter Fitting #4 to 3/8-24 IF Male is a precision hydraulic and brake line adapter engineered for applications requiring reliable fluid transfer between dissimilar fitting sizes. Designed by RUSSELL, a trusted name in fluid system components, this straight adapter bridges 4 AN male connections to 3/8-24 inverted flare female ports, making it essential for custom brake system builds, restoration projects, and high-performance hydraulic installations where exact fitment is non-negotiable.

Constructed from zinc-plated steel, this adapter delivers corrosion resistance and durability in demanding under-hood environments. The inverted flare female connection accepts 3/16-inch hardline tubing, creating a leak-free seal critical to brake system integrity and safety. The 3/8-24 thread pitch on the female side meets industry standards for inverted flare fittings, while the 4 AN male end provides a straight-through design that minimizes turbulence and pressure drop across the junction. The compact footprint—measuring 2.65 x 1.65 x 4.8 inches and weighing just 0.22 pounds—allows installation in tight engine bay spaces without compromising accessibility or serviceability.

Professionals and enthusiasts favor this adapter when connecting modern AN-spec brake lines to classic or OEM inverted flare systems, or when upgrading aging hardline networks with contemporary hose assemblies. It is particularly valuable in street rods, vintage muscle car restorations, race car brake system modifications, and custom hydraulic layouts where multiple fitting standards must coexist. Proper installation requires careful thread engagement and torque application to prevent leaks; always verify line compatibility and inspect the adapter before pressurization to ensure peak braking performance and safety.