View Full Version : School me on flares....


eschoendorff
01-01-2006, 12:29 PM
What's a double flare? What's a bubble flare? What's the difference?

I know that you need to flare the ends of brake lines... but I am unsure about the difference between single/double/bubble flares and 45* vs. 37*.

I am not planning on doing a flaring job, but the criosity has finally gotten the best of me. So, can anyone give me an idiot-proof explanation, preferably with pics? :bounce:

Satatic
01-01-2006, 12:40 PM
Single flare is when you just drive the cone thing down into the tube and make it flare out. Double flare is when you take your single flare and you use an adaptor that comes in the kit to make the outsides of the flare shrink inward again. Then the adaptor is removed and the tube is reflared. So basically you have what looks like a single flare only its folded over to make it uhhh two flares thick? If that makes sense. I guess it would be for strength. Now a bubble flare I believe is when you use only the adaptor and it makes the tube bubble outwards. I'm not positive about that one though. Not sure about the other two, I think they have something to do with stainless steel lines.

JohnZ
01-01-2006, 01:01 PM
SAE double flares (45 degrees) are used on brake and fuel lines; 37-degree flares are used on AN fittings (Aeroquip, Russell, Earl's, etc.).

swgray
01-01-2006, 03:32 PM
Single flares aren't used in brake lines. Used in things like icemaker water lines. Works better in copper, as steel would tend to split.

Bubble flares and double flares are used in brake lines. Double flares are made at first using an adapter to create the bubble flare, then flared again without the adapter.

Here is a link with pictures:

http://www.carcraft.com/howto/50919/index.html

kartracer55
01-01-2006, 03:43 PM
There are singleand double flares, but there are also different shapes of these falres different companies use, dont ask me on specifics, I dont know. If your looking for a flaring kit, make sure it has the adapters to do double and bubble flares. you press in the adapter witch causes the tube to bulge, then you take the adapter out and "crush" the bubbled portion to fold it over.
One nice feature in these tools to look for is "threading'' inside the holes on the flaring bar, which keep the tube in place. As you probably figured out, the angle refers to the "taper" of the flare off center. I have only made 45* flares, but id imagine the process for other angles is similar.

Jim

eschoendorff
01-01-2006, 05:29 PM
Single flares aren't used in brake lines. Used in things like icemaker water lines. Works better in copper, as steel would tend to split.

Bubble flares and double flares are used in brake lines. Double flares are made at first using an adapter to create the bubble flare, then flared again without the adapter.

Here is a link with pictures:

http://www.carcraft.com/howto/50919/index.html


WOW! That is a great resource. I learned alot... thanks for posting that!


BTW, Anyone know what "AN" as in AN fitting stands for? What's the difference? :headscrat

danski0224
01-01-2006, 05:33 PM
I think it stands for Army Navy.

Stuart in MN
01-01-2006, 06:00 PM
Yes, a/n originally stood for Army Navy. They are the 37 degree fittings, and originally were used only by the military. After WWII, when a/n fittings and hoses started showing up in surplus stores the hot rodders started using them.

Satatic
01-01-2006, 07:34 PM
I heard on TV (Trucks! to be exact) that stainless steel lines require a 33 degree single flare. Perhaps he said 37. Can anyone confirm? I plan on using stainless lines on my car.

Fast Orange
01-01-2006, 07:50 PM
I've heard a couple of different thing on s/s brake lines-I'm not 100% sure on either,but you could check with Inline Tube and Classic Industries-both offer premade s/s hardlines.
1) All s/s brakelines must be 37 degrees-flares will crack/deform at 45 degrees.
2)S/S lines must be a certain alloy of stainless,otherwise it will split at flare and at seam in tubing.

George :cool:

kartracer55
01-01-2006, 09:39 PM
I've heard a couple of different thing on s/s brake lines-I'm not 100% sure on either,but you could check with Inline Tube and Classic Industries-both offer premade s/s hardlines.
1) All s/s brakelines must be 37 degrees-flares will crack/deform at 45 degrees.
2)S/S lines must be a certain alloy of stainless,otherwise it will split at flare and at seam in tubing.

George :cool:

They come in 45... My dad ordered replace ment SS for his 68 Olds and they were 45s I believe... At least the ones leaving the m/c are anyway...

Jim

swgray
01-01-2006, 10:08 PM
Here's another link about this subject.

http://www.inlinetube.com/