4an x 9/16-18 Brake Adapter Fitting Steel

The 4AN x 9/16-18 Brake Adapter Fitting Steel from FRAGOLA is an essential component for custom brake system builds and modifications where hose-to-hardline transitions demand reliable performance. This adapter fitting bridges the gap between -4 AN hose assemblies and 9/16-18 threaded ports commonly found on master cylinders, proportioning valves, and brake distribution blocks. Whether you're upgrading a classic muscle car's braking system, fabricating a custom race car platform, or modernizing drum-to-disc conversions, this steel fitting ensures secure connections that handle the hydraulic pressures inherent in high-performance and street applications.

Constructed from durable steel, this adapter fitting provides superior corrosion resistance and mechanical strength compared to aluminum alternatives, making it ideal for long-term reliability under repeated brake cycling and thermal cycling conditions. The 9/16-18 thread pitch is the industry standard for many OEM and aftermarket brake system components, ensuring compatibility with a wide range of valve and cylinder designs. The -4 AN port accepts standard AN hose fittings with JIC 37-degree flare ends, creating leak-free connections that meet or exceed SAE standards for automotive hydraulic systems. FRAGOLA's precision manufacturing ensures tight tolerances and consistent thread engagement, critical factors when safety-critical brake systems are involved.

Mechanics and fabricators building custom brake systems for street rods, track cars, and modern performance builds rely on this fitting to eliminate corrosion-prone factory fittings and create clean, functional layouts. It's particularly valuable when integrating proportioning valves, adjustable brake bias blocks, or modern master cylinders into vehicles with updated suspension and braking geometry. Installation requires only standard wrenches and basic plumbing knowledge—wrap the fitting with PTFE thread tape for added sealing assurance. This single fitting becomes a foundational piece in hydraulic system integrity, directly impacting brake pedal feel, modulation, and overall stopping performance.