Fuel Tank Filler Bung And Cap, Weld On

OVERVIEW

When you''re pushing the limits in a custom sand rail or a high-performance Baja Bug, the last thing you want to worry about is a leaky or unreliable fuel filler neck. This EMPI Fuel Tank Filler Bung and Cap assembly is the gold standard for fabricators looking to create a secure, high-flow fueling point on any custom aluminum or steel fuel cell. Unlike cheap plastic alternatives or aging OEM setups, this weld-on unit provides a rock-solid, vibration-resistant connection that handles the rigors of off-road racing and street performance alike. The precision-machined threads ensure a smooth operation every time you hit the gas station or the pits, while the heavy-duty O-ring creates a vapor-tight seal that prevents fuel splash-back and hazardous fumes from escaping during high-angle maneuvers.

Crafted from premium-grade T6 aluminum, this filler bung isn''t just about function; it adds a clean, professional finish to your engine bay or fuel tank area. Whether you''re building a custom center-mount tank for a Manx-style buggy or modifying a stock Beetle tank for a high-volume racing application, the weld-on design allows for total creative freedom in placement and orientation. The knurled grip on the cap is designed for easy removal even when wearing racing gloves, ensuring that your pit stops are as efficient as possible. By choosing an EMPI-engineered component, you''re investing in decades of air-cooled heritage and proven reliability that has been tested on the toughest dunes and tracks across the globe. This is the essential hardware for any builder who demands perfection in their fuel delivery system.

FITMENT

While this is a universal weld-on component designed for custom fabrication, it is most commonly utilized in the following air-cooled Volkswagen and off-road applications:

• VW Beetle (All Years): Perfect for custom front-trunk fuel cells or racing fuel tanks.
• VW Karmann Ghia: Ideal for high-performance builds requiring modified fuel access.
• VW Bus / Type 2 (1950-1979): Often used in custom center-mount or under-chassis tank fabrications.
• VW Type 3 (Fastback, Notchback, Squareback): Used for custom fuel storage solutions.
• VW Thing (Type 181): A rugged upgrade for off-road trekking and military-style builds.
• Dune Buggies & Sand Rails: The industry standard for custom-built aluminum fuel tanks on tube chassis.
• Baja Bugs: Designed to withstand the vibration and impact of desert racing.
• Meyers Manx & Clones: Provides a professional finish for center-fill tank setups.

SPECS

• Material: High-grade T6 Billet Aluminum for superior weldability and corrosion resistance.
• Installation Method: Weld-on (Designed for integration into aluminum tanks or filler necks).
• Cap Style: Low-profile screw-in cap with aggressive knurling for maximum finger grip.
• Seal Type: High-durometer, fuel-resistant rubber O-ring for a leak-proof interface.
• Weight: 0.51 lbs (lightweight yet structurally robust for racing applications).
• Finish: Natural machined aluminum (can be polished, brushed, or anodized to match your build).
• Compatibility: Safe for use with standard pump gasoline, high-octane racing fuels, and E85.
• Part Number: EMPI AC201005 (Cross-reference: 17-2529-0).

PRO TIPS

1. Prioritize Proper Surface Preparation

When welding this aluminum bung to your tank, cleanliness is absolutely paramount. Aluminum forms an oxide layer almost immediately when exposed to air, which can lead to porous welds and fuel leaks. Use a dedicated stainless steel wire brush that has never touched steel to clean both the bung and the tank surface. Follow this up with a wipe-down using high-purity acetone. Ensuring a surgically clean weld zone will result in a professional-grade bead that won''t crack or weep fuel under the pressure of off-road vibrations.

2. Manage Heat Soak During Welding

Because this bung is precision-machined, excessive heat during the TIG welding process can cause the threads to distort slightly, making the cap difficult to install or remove. I recommend "back-stepping" your welds or using a heat-sink if possible. Many pros will actually thread a sacrificial steel or aluminum plug into the bung during the welding process to help maintain the circularity of the threads. Let the piece air-cool naturally; never quench it in water, as this can cause the aluminum to become brittle and prone to stress fractures near the weld seam.

3. Address Fuel System Venting

It is vital to remember that this cap is a non-vented design to ensure a 100%