3/16 Brake Line Tee, for Brake Light Switch

OVERVIEW

When you''re deep into a custom air-cooled project, whether it''s a ground-up sand rail build, a rugged woods buggy, or a classic Beetle being converted to American-style plumbing, the details in your braking system are what separate a professional build from a dangerous one. This Allstar Performance 3/16-inch brake line tee is the essential component for builders who are running standard 3/16-inch (3/8-24 thread) domestic brake lines but still need a reliable way to trigger their brake lights. In many custom master cylinder configurations, especially those used in off-road racing or simplified street rod setups, there isn''t a dedicated port for the hydraulic brake light switch. This tee solves that problem by providing a centralized junction that accepts two 3/16-inch lines and features a dedicated 1/8-inch NPT port specifically designed for a standard hydraulic pressure switch.

At Appletree Automotive, we know that reliability is everything when you''re out on the dunes or navigating traffic. This tee is manufactured from high-strength materials to ensure it can handle the extreme pressures generated by high-performance braking systems without flexing or leaking. While many stock Volkswagens utilize metric M10x1.0 plumbing, many aftermarket pedal assemblies and master cylinderslike those from CNC or Wilwoodutilize American 3/16-inch inverted flare fittings. This tee is the perfect bridge for those systems, allowing you to maintain a clean, organized brake line layout while ensuring your brake lights activate the moment you hit the pedal. It is a compact, "set-it-and-forget-it" component that is vital for both safety and street-legal compliance in any custom VW-based vehicle.

FITMENT

This brake line tee is a universal component designed for vehicles utilizing 3/16-inch American (3/8-24 thread) brake lines. It is commonly used on the following applications:

• Custom Dune Buggies & Sand Rails: Ideal for vehicles using aftermarket pedal assemblies (CNC, Neal, etc.).
• VW Beetle / Ghia / Type 3: For owners who have converted their stock metric lines to 3/16-inch American plumbing.
• Manx-Style Buggies: Perfect for simplifying the wiring and plumbing of a shortened chassis.
• Off-Road Race Cars: Used in specialized braking circuits where a hydraulic switch is required mid-line.
• Hot Rods & Custom Builds: Any application requiring a 1/8-inch NPT sender port within a 3/16-inch line.

SPECS

Precision engineering meets rugged durability with these technical specifications:

• Line Port Size: Two ports for 3/16-inch Brake Line (3/8-24 Inverted Flare).
• Switch Port Size: One port for 1/8-inch NPT (National Pipe Thread).
• Material: High-quality brass for superior corrosion resistance and sealing.
• Thread Type: SAE / American Standard.
• Application: Hydraulic brake systems only.
• Manufacturer: Allstar Performance.
• Part Number: 889-F (ALL50137).

PRO TIPS FROM THE SHOP

1. Identify Your Threads Before Installation

One of the most common mistakes we see in the shop is builders trying to force a metric M10x1.0 VW brake line into this 3/8-24 tee. While they look incredibly similar to the naked eye, the thread pitch is different. Always verify that your hard lines are 3/16-inch American with 3/8-24 nuts. If you are working on a purely stock German VW, you will likely need a metric-to-standard adapter or you should look for our metric-specific tees. Forcing the wrong thread will strip the brass and lead to a catastrophic brake failure.

2. Seal the NPT Port Correctly

This tee uses two different types of sealing. The 3/16-inch line ports are "Inverted Flare," which means the seal happens at the flare of the tubedo NOT use Teflon tape or sealant on these threads. However, the 1/8-inch NPT port for the brake light switch is a tapered pipe thread, which requires a seal on the threads. We recommend using a tiny amount of high-quality liquid thread sealant or a single wrap of Teflon tape on the brake light switch threads only, ensuring no tape hangs over the end of the switch where it could enter the hydraulic fluid stream.

3. Mount the Tee Securely

In off-road environments like sand dunes or rocky trails, vibration is the enemy of your brake lines. Because this tee is heavy compared to the lines it connects, you should never leave it "floating" in the air. Use a cushioned P-clamp or a dedicated mounting bracket to secure the tee or the lines immediately adjacent to it to the chassis. This prevents the weight of the tee and the switch from vibrating and causing "metal fatigue" at the flares, which is a leading cause of line cracks and fluid leaks in custom buggies.