1/4" NPT To 1/2" Barb Straight Barb Hose Fitting (Billet Oil Filler, Maxi Pump)

These 1/4″ NPT to 1/2″ barbed hose fittings are designed for use on aircooled Volkswagen engines where smaller threaded ports need to be adapted to larger 1/2″ breather or oil hoses. Common applications include oil filler breather outlets and Maxi oil pump fittings, making them an essential component in both standard and performance engine builds.

Each fitting features a 1/4″ NPT tapered thread, allowing it to screw securely into oil filler necks, breather boxes, or Maxi oil pump outlets. The tapered thread ensures a tight, leak-resistant seal when installed with suitable thread sealant. On the hose side, the 1/2″ barb provides a strong and secure connection for breather or oil hose, preventing disconnection under pressure or crankcase ventilation flow.

These fittings are particularly important in crankcase breather systems. As engine pressure builds inside the crankcase, gases must be vented efficiently to prevent oil leaks and maintain engine health. These fittings allow larger diameter breather hoses to be connected to smaller threaded outlets, improving airflow and reducing internal pressure. They are also commonly used on Maxi oil pumps where auxiliary outlets require connection to external oil lines.

For installation, you may also require 1/2″ breather or oil hose, hose clamps, and thread sealant. Depending on your setup, these may be used alongside breather boxes, oil catch tanks, or external oil system components.

Sold separately, these fittings provide a reliable solution for both breather and oil system connections.

Vehicle Fitment

Aircooled VW:

• Beetle (1949–1979) – All engines
• Beetle Cabriolet (1949–1979)
• T2 Split Bus (1950–1967)
• T2 Bay Window (1968–1979)
• T25 / T3 Aircooled (1979–1983)
• Karmann Ghia (1955–1974)
• Type 3 (1961–1973)
• Trekker (1968–1983)
• Buggy / Baja (Type 1 based, 1949–1979)

Watercooled VW:

• T25 / T3 Watercooled (1983–1992) – when fitted with custom breather or oil systems

Key Features

• 1/4″ NPT male thread (tapered for secure sealing)
• 1/2″ hose barb for breather or oil hose connection
• Ideal for oil filler breather outlets and Maxi oil pump fittings
• Improves crankcase ventilation when used with larger hoses
• Suitable for performance and upgraded oil systems
• Durable, leak-resistant construction
• Supplied Separately (1 fitting)