{"id":1090,"date":"2026-10-11T13:51:47","date_gmt":"2026-10-11T13:51:47","guid":{"rendered":"https:\/\/www.jlinlin.com\/?post_type=product&p=1090"},"modified":"2026-10-12T02:41:50","modified_gmt":"2026-10-12T02:41:50","slug":"male-to-metric-inverted-female-flare-thread-fitting-adapter-straight-silver-1pc-2pcs","status":"publish","type":"product","link":"https:\/\/www.jlinlin.com\/index.php\/product\/male-to-metric-inverted-female-flare-thread-fitting-adapter-straight-silver-1pc-2pcs\/","title":{"rendered":"Male to Metric 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\n
Specification<\/strong><\/td>\nDetails<\/strong><\/td>\n<\/tr>\n<\/thead>\n
Package<\/strong><\/td>\n1x or 2x AN Male to Metric 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>\nM10x1.0, M10x1.25<\/td>\n<\/tr>\n
Fitting Female Port Type<\/strong><\/td>\nMetric Inverted Flare, female<\/td>\n<\/tr>\n
Fitting Compatible Line<\/strong><\/td>\n4.75mm metric or 3\/16 inch brake line<\/td>\n<\/tr>\n
Fitting Connector Type<\/strong><\/td>\nStraight reducing adapter, male to female<\/td>\n<\/tr>\n
Fitting Sealing Method<\/strong><\/td>\n\n
    \n
  • \nAN side: <\/strong>37-degree metal-to-metal flare seal.<\/li>\n
  • \nMetric side:<\/strong> metal-to-metal flare seal.<\/li>\n<\/ul>\n

    Confirm your line uses a matching flare form before ordering<\/p>\n<\/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>\n1,500 PSI (Max)<\/td>\n<\/tr>\n
Fitting Temperature Range<\/strong><\/td>\n-63\u00b0F to 252\u00b0F<\/td>\n<\/tr>\n
Fitting Color<\/strong><\/td>\nNatural Stainless<\/td>\n<\/tr>\n
Fitting Application<\/strong><\/td>\nMetric brake and clutch hydraulic lines, master cylinders, proportioning valves, hydraulic handbrake cylinders, distribution blocks, hardline to flexline transitions. ABS module ports vary in flare form and must be confirmed individually<\/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 Reference<\/h3>\n\n\n\n\n\n\n\n\n
AN Side<\/strong><\/td>\nMetric Side<\/strong><\/td>\nBrake Line<\/strong><\/td>\n<\/tr>\n<\/thead>\n
3AN, 3\/8-24 UNF<\/td>\nM10x1.0<\/td>\n4.75mm or 3\/16 inch<\/td>\n<\/tr>\n
3AN, 3\/8-24 UNF<\/td>\nM10x1.25<\/td>\n4.75mm or 3\/16 inch<\/td>\n<\/tr>\n
4AN, 7\/16-20 UNF<\/td>\nM10x1.0<\/td>\n4.75mm or 3\/16 inch<\/td>\n<\/tr>\n
4AN, 7\/16-20 UNF<\/td>\nM10x1.25<\/td>\n4.75mm or 3\/16 inch<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

Thread size alone does not confirm fitment on a metric brake system. M10 ports exist with more than one seat form, and the tube nut is identical on all of them. Identify the flare on your line before ordering.<\/em><\/p>\n

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

About this item<\/h2>\n

The performance brake market in the United States runs on AN<\/strong> threads. Your car does not. Adjustable proportioning valves, hydraulic handbrake<\/strong> cylinders, braided lines and gauge blocks all arrive with 3\/8-24 or 7\/16-20, while the factory ports on a Japanese or European chassis are M10x1.0<\/strong> or M10x1.25<\/strong>. This metric brake line adapter<\/strong> is the joint between those two worlds, and it lets the factory hardline stay exactly where it is.<\/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 metric inverted flare female seat. Compare the female seat against your own line before installing.<\/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

Metric female seat.<\/strong> A machined cone, not a flat shoulder. Your flared tube end presses directly against this surface. If your line has a raised ring rather than a folded funnel, you have a bubble flare and need a different part.<\/p>\n

\"\"<\/p>\n

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 handbrake cylinder port where clearance is usually tight.<\/p>\n<\/div>\n

Metric Brake Line to AN Conversion: What M10x1.0 and M10x1.25 Actually Fit<\/h3>\n

Both M10x1.0<\/strong> and M10x1.25<\/strong> are used on 4.75mm metric brake line<\/strong>, which is dimensionally interchangeable with 3\/16 inch<\/strong> line. The thread does not tell you the tube size. What separates the two is pitch, 1.0mm against 1.25mm between crests, and they are close enough to start cross-threading if forced.<\/p>\n

On the AN side, 3AN<\/strong> is 3\/8-24 UNF and 4AN<\/strong> is 7\/16-20 UNF, both sealing on a 37-degree cone. Four combinations are available so the AN size can follow the line you are running rather than the port you are leaving.<\/p>\n

Use a thread pitch gauge rather than judging by eye. On a metric brake system the two pitches look identical across the threads, and the difference only shows up as a joint that will not seat.<\/p>\n

Bubble Flare vs Inverted Flare: How to Check Before You Order<\/h3>\n

Matching the thread is half the job. M10x1.0<\/strong> exists in more than one seat geometry and they are not interchangeable, which is the single most common reason a metric brake adapter comes back.<\/p>\n

A bubble flare<\/strong>, common on European systems and on many Bosch ABS units, forms a raised ring set back from the end of the tube. A double or inverted flare<\/strong> folds the tube end back into itself and reads as a small funnel. Both take the same M10 tube nut, so the nut tells you nothing. European standards name them directly: DIN 74234 Form E<\/strong> is the inverted flare, Form F<\/strong> is the bubble or convex flare.<\/p>\n

Take a flashlight to the end of your line before ordering. Funnel means inverted flare. Raised ring means bubble flare. Ten seconds now, or a return later.<\/p>\n

Hydraulic Handbrake, Proportioning Valve and Caliper Line Fitment<\/h3>\n

The most common use for a metric to AN brake adapter<\/strong> is a hydraulic handbrake<\/strong> install. Aftermarket handbrake cylinders ship with AN or SAE ports while the factory line feeding the rear circuit is M10, and interrupting that circuit creates a transition at each end. Plan for at least two.<\/p>\n

Beyond that: master cylinder outlets, adjustable proportioning valves<\/strong>, distribution blocks, and the hardline to flexline transitions on a track brake conversion. Many metric calipers use a banjo port rather than a threaded port, and for those the metric stainless banjo bolt<\/a>\u00a0is the correct part instead.<\/p>\n

ABS<\/strong> modules need a separate word. Many use M10x1.0, so the thread often matches, but a large share are bubble flare rather than inverted flare. Confirm the seat before ordering for an ABS port specifically.<\/p>\n

Stainless Steel Metric Brake Fittings and Why the Seat Finish Matters<\/h3>\n

On a fitting that seals entirely on 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 4.75mm joint, that finish decides whether the seat mates across its full face or touches in three places.<\/p>\n

Stainless matters more on a metric car than most people expect. Factory metric brake fittings are usually plated steel, and after a few winters they seize into whatever they thread into. A stainless steel brake fitting<\/strong> comes back out the next time the system does, which is the difference between removing a proportioning valve and destroying one.<\/p>\n

How Many M10 to AN Brake Adapters Do You Need<\/h3>\n

Count the transitions in your plan, not the components.<\/p>\n

One<\/strong> covers a single tap, such as a gauge feed or one end of a handbrake circuit. Two<\/strong> covers most real jobs, because brake transitions arrive in pairs: a master cylinder has two outlets, a circuit has two ends, and a left and right caliper feed are a pair by definition.<\/p>\n

If you are unsure, take the two pack. A build stopped on a Saturday because one fitting is short costs more than the fitting, and an unopened stainless adapter has no shelf life.<\/p>\n

What Is In The Box<\/h3>\n