Brake line flare: Bubble or double?
JWA...sorry, should have been more specific. Before a couple weeks ago, I never flared ANYTHING. Up to this point in my mechanical endeavors (and I'm 41!), I've always used unions and/or compression fittings to get a custom-length line. I, too, was always told to use a double-flare, so when I did those trans cooler lines, that's what I did. I tried the Chinese tool first...the flares looked terrible, and I thought it was something I was doing wrong. Then I borrowed the KD tool, and they were perfect. So...the right tool for the right job.
So I don't know if a single-flare works well in anything outside of an oil furnace...but I DO know I gotta order me that KD double-flare tool set pretty damn soon!
Pat
So I don't know if a single-flare works well in anything outside of an oil furnace...but I DO know I gotta order me that KD double-flare tool set pretty damn soon!

Pat
Pat I understand and was asking only because much like yourself I've not done a lot of flaring of any lines, automotive style anyway. You're right to ask and for me I find those who've done something before tend to have the best advice to share. I hope I didn't come across as snarky.
A good quality flaring tool set might sit in the tool box more often than its used BUT when I need to stomp the brakes I wanna know the pressure is gonna hold!
KD makes good tools---can't really go wrong with them. I've used two outfits for online tools, USA Tool Warehouse and Tool Topia. Amazon is a good place with a ton of choices and prices too.
Hope this upcoming project goes smoothly---you'll be giving us flaring advice soon I'm sure!
A good quality flaring tool set might sit in the tool box more often than its used BUT when I need to stomp the brakes I wanna know the pressure is gonna hold!

KD makes good tools---can't really go wrong with them. I've used two outfits for online tools, USA Tool Warehouse and Tool Topia. Amazon is a good place with a ton of choices and prices too.
Hope this upcoming project goes smoothly---you'll be giving us flaring advice soon I'm sure!
Both double flare and bubble flare have been used on vehicles for a long time and they are not interchangeable. A single flare has never been allowed by SAE or DOT in the USA. It's even in the Federal Register under FMVSS code that brake lines have to conform to either of those conventions, and since state vehicle laws defer to the federal vehicles laws, single flares are never allowed.
Since I used to do some work in accident investigation, I'll just pass on that you do not to be the one who installs a brake line with a single flare if there ever is an accident due to the flare cracking. Even if you the vehicle owner you will see the insurance company representing you leave the courtroom faster then a speeding bullet.
Since I used to do some work in accident investigation, I'll just pass on that you do not to be the one who installs a brake line with a single flare if there ever is an accident due to the flare cracking. Even if you the vehicle owner you will see the insurance company representing you leave the courtroom faster then a speeding bullet.
You can get a heads-up on what type of flare and the thread size of the fitting on the brake line by looking up on line (Autozone or Advance Auto Parts) for the brake hose it will connect to. Under the description of the brake hose it will give the thread size and type of flare. However, if the other end of the brake line runs to ABS hydraulic unit, be prepare for the unexpected because God only knows what type of flare or size fitting (if you're lucky its not a nut instead of a fitting...Ford is full of surprises).
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