Brake Line Adapter -4 to 3/16 Inverted Flare ALL50105

OVERVIEW

When you''re pushing your air-cooled VW to the limit on the street or across the dunes, your braking system is the last place you should ever compromise. The Allstar Performance -4 AN to 3/16-inch Inverted Flare Brake Line Adapter (ALL50105) is the professional choice for builders who demand a rock-solid transition between traditional hard lines and modern high-pressure braided hoses. This isn''t just a simple union; it is a bulkhead-style fitting designed to pass through chassis tabs or frame rails, providing a secure anchor point that eliminates line vibration and potential fatigue. Whether you are plumbing a custom rail, a narrowed beam Beetle, or a high-performance street Ghia, this adapter allows you to utilize -4 AN braided lines for superior pedal feel while maintaining the reliability of standard 3/16-inch inverted flare hard lines for the rest of your system.

Constructed from high-grade aluminum and engineered for a precision fit, this adapter solves the common headache of mating mismatched plumbing standards. The 9/16-inch threaded body is robust enough to handle the rigors of off-road racing, and the included jam nut ensures that once your lines are set, they stay put. In the world of custom VW builds, routing brake lines can be a nightmare, but using a bulkhead adapter like the ALL50105 allows for a clean, professional-grade installation that looks as good as it performs. By moving to a -4 AN interface, you open up a world of possibilities for custom hose lengths and high-clearance fittings that standard metric or SAE hard lines simply cannot offer. Trust Appletree Automotive to provide the essential plumbing components that keep your vintage ride stopping on a dime every single time.

FITMENT

This is a universal high-performance adapter frequently used in custom air-cooled VW applications, including but not limited to:

• Volkswagen Beetle: All years (Custom brake plumbing upgrades)
• Volkswagen Karmann Ghia: All years (Disc brake conversions and custom routing)
• Volkswagen Bus (Type 2): 1950-1979 (Ideal for dual-circuit master cylinder upgrades)
• Volkswagen Type 3: Squareback, Fastback, and Notchback models
• Meyers Manx & Dune Buggies: Essential for chassis-to-trailing arm transitions
• Sand Rails & Off-Road Cars: Perfect for bulkhead mounting on tube frames
• Custom Hot Rods: Any vehicle utilizing a 3/16-inch inverted flare hard line system

SPECS

• Part Number: ALL50105
• Fitting Side A: -4 AN Male
• Fitting Side B: 3/16-inch Inverted Flare (Female)
• Body Style: Bulkhead with Jam Nut included
• Mounting Thread Size: 9/16-18
• Material: High-Strength Lightweight Aluminum
• Finish: Natural / Anodized for corrosion resistance
• Application: High-pressure hydraulic brake systems

PRO TIPS

1. Secure the Bulkhead Properly

When installing the ALL50105, always ensure you are mounting it through a dedicated steel chassis tab or a reinforced section of the frame. Never let the adapter "float" or hang solely by the tension of the brake lines. Use a 9/16-inch drill bit for a snug fit, and ensure the jam nut is torqued down tightly against the mounting surface. This prevents the fitting from rotating when you are tightening or loosening your brake lines in the future, which protects your hard lines from twisting and snapping.

2. Master the Double Flare

Since this adapter accepts a 3/16-inch inverted flare, the hard line mating to it must have a perfect 45-degree double flare. Before assembly, inspect your flare for any cracks or uneven edges. A common mistake is over-tightening the inverted flare side; remember that the seal is created by the metal-to-metal contact of the flare, not the threads. Tighten it until it is snug, then give it an additional 1/8 to 1/4 turn. If it leaks, don''t just crank it down; disassemble it and check the integrity of the flare itself.

3. No Thread Sealant Required

It is a common misconception that Teflon tape or pipe dope should be used on brake fittings. In the case of -4 AN and inverted flare connections, the threads do not provide the sealthe flared surfaces do. Adding sealant to these threads can actually prevent the flares from seating properly and, worse, can introduce debris into your hydraulic system that could clog a wheel cylinder or caliper. Keep the threads clean and dry, and let the precision-machined angles of the Allstar Performance adapter do the sealing for you.