Brake lines sizes/flare types

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340inabbody

340inabbody

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Slow progress but am ready to bench bleed my master cylinder in the car. I need to find two short brake lines to hook up to the master cylinder. I found a set but it came with two different sizes and crimp styles.

I am not familiar with the different sizes.

Can someone please explain what types of flares are used on my master cylinder and what thread type as well?

The picture of the lines I have and my MC are shown below. One set of lines looks too large.

Thanks for taking the time to comment.

IMG_3007.jpeg


IMG_3008.jpeg
 
Plymouth 65 said:
Can't help with the sizes but all brake lines are double flared. 65
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Thanks not sure how that translates to being able to find what fits the MC. I guess Ill make a mess all over and see what fits. Looks like there are several thread sizes.
 
The threads in brake lines are called tube threads. They are straight threads, just like a bolt. They are not pipe thread. They don't have a taper, since the flare itself does the sealing. There's no real set standard as to what fitting size is used with what size line although there should be. In other words, you could have 1/4" brake line, for example with a 1/2" thread tube fitting, or 9/16, or whatever. Whatever fits your master cylinder.
 
Master cylinders are not necessarily "standard" flare threads, by design. This was to keep the assembly line drones from getting them wrong. Google up a brand name (Edelman, etc) brass catalog, and they will list the standard flare nut sizes.


For example, in the above, page G18 are standard flare nuts for US tubing

invertedflare.jpg

Note that these sizes DO NOT cover the rather special ones used on master cylinders. Those are somewhat proprietary. Someone may make them, but I know not who. Back in the days when brake controllers (for trailer brakes) connected via the master cylinder tap off, there were all sorts of T adapters for this,and they could be tricky
 
67Dart273 said:
Master cylinders are not necessarily "standard" flare threads, by design. This was to keep the assembly line drones from getting them wrong. Google up a brand name (Edelman, etc) brass catalog, and they will list the standard flare nut sizes.


For example, in the above, page G18 are standard flare nuts for US tubing

View attachment 1716296910
Click to expand...
Yeah, I knew there was a chart. That's what they're SUPPOSED to be, but that ain't always the case. lol In fact, I've run into SAE tubes with fu$%!ng METRIC nuts flared on. lol
 
Cuda Al said:
1/2-20 and 9/16-20 inverted flare with 3/16 line


Alan
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I found this searching here by Dr. Diff said the same thing.
I can’t be sure until I try different connections. Not the best way to figure it but looks like I don’t have a choice. The lines DID HOWEVER fit my original factory MC!

IMG_3024.png
 
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