{"id":977,"date":"2026-10-11T13:50:09","date_gmt":"2026-10-11T13:50:09","guid":{"rendered":"https:\/\/www.jlinlin.com\/?post_type=product&p=977"},"modified":"2026-10-12T02:41:26","modified_gmt":"2026-10-12T02:41:26","slug":"3-4an-male-to-3-8-24-inverted-female-flare-thread-fitting-adapter-straight-silver-1pc-2pcs","status":"publish","type":"product","link":"https:\/\/www.jlinlin.com\/index.php\/product\/3-4an-male-to-3-8-24-inverted-female-flare-thread-fitting-adapter-straight-silver-1pc-2pcs\/","title":{"rendered":"3\/4AN Male to 3\/8-24 Inverted Female Flare Thread Fitting Adapter Straight Silver 1PC\/2PCS"},"content":{"rendered":"

Specifications<\/h2>\n<\/p>\n

Product Details<\/h2>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Specification<\/strong><\/td>\nDetails<\/strong><\/td>\n<\/tr>\n<\/thead>\n
Package<\/strong><\/td>\n1x or 2x AN Male to Inverted Flare Female Brake Fitting Adapter<\/td>\n<\/tr>\n
Brand<\/strong><\/td>\n<\/td>\n<\/tr>\n
Fitting Material<\/strong><\/td>\nUNS S30300 Stainless Steel<\/td>\n<\/tr>\n
Fitting Male Thread Size<\/strong><\/td>\n3\/8-24 UNF (3AN), 7\/16-20 UNF (4AN)<\/td>\n<\/tr>\n
Fitting Male Thread Type<\/strong><\/td>\nAN (Army-Navy) 37-degree flare, male<\/td>\n<\/tr>\n
Fitting Female Port Size<\/strong><\/td>\n3\/8-24 Inverted Flare (for 3\/16″ line), 7\/16-24 Inverted Flare (for 1\/4″ line)<\/td>\n<\/tr>\n
Fitting Female Port Type<\/strong><\/td>\nInverted Flare, SAE 45-degree double flare seat (SAE J512)<\/td>\n<\/tr>\n
Fitting Connector Type<\/strong><\/td>\nStraight reducing adapter, male to female<\/td>\n<\/tr>\n
Fitting Sealing Method<\/strong><\/td>\nAN side: 37-degree metal-to-metal cone. Inverted flare side: 45-degree metal-to-metal seat. No thread sealant or PTFE tape on either side<\/td>\n<\/tr>\n
Fitting Compatible Media<\/strong><\/td>\nDOT 3, DOT 4 and DOT 5.1 brake fluid, hydraulic clutch fluid<\/td>\n<\/tr>\n
Fitting Working Pressure<\/strong><\/td>\n\n
\n1,500 PSI (Max)<\/span>\n<\/td>\n<\/tr>\n
Fitting Temperature Range<\/strong><\/td>\n\n
\n-63\u00b0F to 252\u00b0F<\/span>\n<\/td>\n<\/tr>\n
Fitting Color<\/strong><\/td>\nNatural Stainless<\/td>\n<\/tr>\n
Fitting Application<\/strong><\/td>\nBrake and clutch hydraulic lines, master cylinders, proportioning valves, residual valves, distribution blocks, hydraulic handbrake feeds, disc brake conversions<\/td>\n<\/tr>\n
Fitting Unit Count<\/strong><\/td>\n1 Count or 2 Count, by variant<\/td>\n<\/tr>\n
Fitting Included Components<\/strong><\/td>\nAdapter only. Tube nuts, flared line and brake fluid not included<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Thread and Line Size Chart<\/h3>\n\n\n\n\n\n\n
Variant<\/strong><\/td>\nAN Male Side<\/strong><\/td>\nInverted Flare Female Side<\/strong><\/td>\nBrake Line<\/strong><\/td>\n<\/tr>\n<\/thead>\n
3AN<\/strong><\/td>\n3\/8-24 UNF, 37-degree cone<\/td>\n3\/8-24, 45-degree seat<\/td>\n3\/16 inch<\/td>\n<\/tr>\n
4AN<\/strong><\/td>\n7\/16-20 UNF, 37-degree cone<\/td>\n7\/16-24, 45-degree seat<\/td>\n1\/4 inch<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Read the 4AN row carefully. The AN side is 7\/16-20<\/strong> and the inverted flare side is 7\/16-24<\/strong>. Same outside diameter, different pitch, and they will cross-thread if forced. Identify your port with a thread pitch gauge before ordering.<\/em><\/p>\n

Description<\/h2>\n<\/p>\n

About this item<\/h2>\n

Almost nobody converts an entire brake system to AN<\/strong> in one pass. You replace the flexible lines, or fit a new master cylinder, or plumb a hydraulic handbrake, and suddenly half the system is AN<\/strong> and half is still factory inverted flare<\/strong>. This adapter lets both halves stay exactly where they are.<\/p>\n

\n\"\"<\/p>\n

Both ends in one view.<\/strong> The pointed end is the 37-degree AN male cone. The open end is the 45-degree inverted flare female seat. Different angles, not interchangeable.<\/p>\n

\"\"<\/p>\n

AN male cone.<\/strong> This face is the entire seal on the AN side. It should reach you unmarked. Any nick across the cone is a leak path and the fitting should not be installed.<\/p>\n

\"\"<\/p>\n

Inverted flare seat.<\/strong> The 45-degree cone machined inside the female port. Your double-flared tube end presses directly against this surface, which is why the tube must be double flared and never single flared.<\/p>\n

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Wrench flats and overall length.<\/strong> Hex sized for a standard flare nut wrench. Length is kept short so the adapter adds minimal offset at a master cylinder or valve port where clearance is usually tight.<\/p>\n<\/div>\n

Same Thread, Different Angle<\/h3>\n

Here is the detail that decides whether your install leaks. A 3AN<\/strong> male thread is 3\/8-24. A 3\/8-24 inverted flare<\/strong> port is also 3\/8-24. The threads will engage each other perfectly. The seats will not.<\/p>\n

AN<\/strong> seals on a 37-degree cone. Inverted flare<\/strong> seals on a 45-degree seat shaped for a double-flared tube end. Thread an AN line straight into an inverted flare port and it will tighten, feel solid, and weep under pedal pressure, because only a narrow band of the two cones is actually touching.<\/p>\n

This adapter carries both geometries on one body: a correct 37-degree cone facing your AN line, a correct 45-degree seat facing your factory tube nut. Pair it with the rest of the AN fitting<\/a> when the build needs more than one transition.<\/p>\n

What the Install Actually Requires<\/h3>\n

Neither end of this adapter takes thread sealant or PTFE tape. Both seal on machined metal, and anything on the threads only holds the seats apart.<\/p>\n

Two things matter more than torque. First, the tube end must be double flared<\/strong>, not single flared, on the inverted flare side. A single flare on steel brake line can pass a bench test and then split under a hard pedal. Second, the seat must be clean<\/strong>. One burr or a fragment of old sealant on a 45-degree seat will hold at idle and let go under load.<\/p>\n

Use a flare nut wrench<\/strong>, never an open-end wrench, and bleed and inspect every joint dry before the vehicle moves under its own power.<\/p>\n

Machined, Not Cast<\/h3>\n

On a fitting that seals entirely on two cone surfaces, surface finish is the seal. UNS S30300<\/strong> is a free-machining stainless grade, chosen because it holds a cleaner finish and tighter concentricity on small-diameter cone work than tougher grades do. On a 3\/16 inch line joint, that finish is the difference between a seat that mates fully and one that touches in three places.<\/p>\n

Stainless also means the adapter will not seize into a component the way a plated steel fitting does after a few winters, which matters the next time the system comes apart.<\/p>\n

Where It Goes<\/h3>\n

Anywhere a factory brake or clutch line has to meet an aftermarket AN<\/strong> line: master cylinder outlets, proportioning and residual valves, distribution blocks, hydraulic handbrake feeds, and the hardline-to-flexline transitions on a disc brake conversion<\/strong>. Where a component uses a banjo port instead of a threaded port, see the stainless banjo bolt<\/a>.<\/p>\n

One place it does not go: most ABS module<\/strong> ports are metric bubble flare rather than SAE inverted flare, and need a different adapter entirely. Identify the port with a thread gauge before ordering.<\/p>\n

Choosing 1 Piece or 2<\/h3>\n

Brake conversions rarely need just one adapter. A master cylinder has two outlets. A front-to-rear circuit has two ends. A left and right caliper feed are a pair by definition.<\/p>\n

Before you order, count the transitions in your plan rather than the components. Most jobs need two. Some need four.<\/strong> A spare in the toolbox costs less than stopping a build halfway through a weekend, and an unopened fitting has no shelf life.<\/p>\n

Package Contents<\/h3>\n