Bulkhead Fittings

AN bulkhead fittings allow fuel, oil, brake, and coolant lines to pass cleanly through firewalls, chassis panels, fuel cell walls, and fabricated enclosures, with a fully sealed connection on both faces of the panel. Flux Hydraulic Masters bulkhead fittings are precision-machined from aircraft-grade 6061-T6 aluminium and hard anodised in black, supplied with a bulkhead lock nut for secure panel mounting.

The range covers straight pass throughs for direct line routing, and 90 degree bulkhead fittings for situations where the hose must immediately run parallel to the panel surface after passing through, eliminating the tight bends that stress hose and fittings over time. Available in AN4, AN6, AN8, AN10, AN12, and AN16 across both styles. Replacement bulkhead nuts are also available individually for custom fabricated panels.

All FLUX bulkhead fittings are compatible with standard AN hose ends and backed by a lifetime warranty.

FAQs

What is a bulkhead fitting and what is it used for?

A bulkhead fitting allows a fluid line to pass cleanly through a panel, such as a firewall, chassis rail, fuel cell wall, or fabricated enclosure with a sealed, leak-free connection on both faces of the panel. Without a bulkhead fitting, passing a hose through a hole leaves the panel unsupported and the hose vulnerable to chafing and vibration damage. Bulkhead fittings are standard practice in motorsport fuel, oil, and brake line routing.

What is the difference between a straight and 90 degree bulkhead fitting?

A straight bulkhead fitting passes the line directly through the panel - the hose continues in the same direction on both sides. A 90 degree bulkhead fitting exits the panel at a right angle, directing the hose run parallel to the panel surface immediately after it passes through. Use a 90 degree when the hose needs to run along the panel rather than away from it - this eliminates the tight bend that would otherwise stress the hose and fitting close to the panel face.

What AN size bulkhead fitting do I need?

Match the bulkhead fitting to the AN size of the hose you are running through the panel. AN6 suits fuel return lines and oil lines on smaller builds. AN8 is the most common size for fuel feed lines on performance cars. AN10 suits high-flow fuel feeds on boosted builds. AN12 and AN16 are used for larger oil, power steering, and cooler circuits. All FLUX bulkhead fittings are available in AN4, AN6, AN8, AN10, AN12, and AN16.

Does the bulkhead fitting come with a lock nut?

No, they are sold separately. The lock nut threads onto the fitting body from the rear face of the panel, clamping the fitting securely in place and preventing rotation. Replacement lock nuts are also available individually in the same collection if needed.

What size hole do I need to drill for a bulkhead fitting?

The hole diameter required depends on the AN size of the fitting. As a general guide: AN4 requires approximately 16mm, AN6 approximately 19mm, AN8 approximately 22mm, AN10 approximately 26mm, AN12 approximately 30mm, and AN16 approximately 37mm. Always verify against the fitting body diameter before drilling - a tight fit is preferable to an oversized hole that allows the fitting to move.

Can I use a bulkhead fitting with PTFE hose?

Yes. FLUX bulkhead fittings accept any standard AN hose end on both sides - PTFE swivel hose ends, push lock hose ends, and full flow swivel hose ends all mate with the 37° JIC flare on the bulkhead fitting. The bulkhead fitting itself is not hose-type specific.

Are FLUX bulkhead fittings suitable for fuel and brake lines?

Yes. FLUX bulkhead fittings are suitable for fuel, oil, brake fluid, coolant, and power steering fluid. The 6061-T6 aluminium construction and anodised finish are compatible with all common automotive fluids. Always ensure the hose and hose ends used with the fitting are also rated for the specific fluid - particularly for brake fluid, where PTFE-lined hose is strongly recommended.