Thread: Stainless steel double flares

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Does anyone know who sells a good double flaring kit that I can use for 3/16 stainless steel brake lines for the hot rod.( Location is Perth Western Australia )
My brake lines have been finished for a while but they were a bastard to seal.
I have had a problem since finishing the rod with the pedal being a little spongey,but I have only found out recently by reading some articles that I needed to install some non return lines due to the booster being under the floor.
Now I want to get hold of a suitable flaring kit that suits stainless steel

Never known anyone who successfully double flaired stainless, it's too brittle. Stainless is commonly done single flair with a JIC fitting at 37 degree rather than the 45 degree of the typical mild steel flair. Maybe that's why you had a problem earlier.

Stainless will work harden as you flare it and you won't be able to successively double flare it----use the 37* AN fittings and "B" nuts with the proper 37 degree flaring tool--

If you have tubing that is thicker wall you may need to anneal the end of the tube with a torch first---this usually only happens on the thicker stuff because the tubing cutter will work harden it while cutting and then the flaring tool will end up splitting it--if this happens just heat the end until it glows and then let air cool

Yes to all of the above advice.

But one more thing to check is to make "absolutely sure" that you have smoothed the seam on the inside of the flare. Stainless is so hard it will not seal with the small bump left on the tubing.

thats why I use seamless tubing

Just to add my 2c. I double flared my S/S brake lines. I too heard that it couldn't be done; too hard, would crack. Then I read either here or on another forum that if you anneal the S/S it will double flare just fine. I tried it and it appears to have worked. I say appeared because other than a few trips to the house from the shop and back it has not been tested on the road. However so far I can find no leaks after bleeding and the afore mentioned trips. After annealing it double flared quite easily.

Jack.

I use the stainless line from Speedway, Its double annealed and double flares easily with a quality tool, I did try some from Summit and this wouldn't double flare very well at all.

I use a Sykes-Pickavant tool

Sorry but you shouldn't be using seamed tube for brakes

Originally Posted by John Palmer

Yes to all of the above advice.

But one more thing to check is to make "absolutely sure" that you have smoothed the seam on the inside of the flare. Stainless is so hard it will not seal with the small bump left on the tubing.

Since the MC is under the floor, did you make sure you have a 10 lb residual valve inline?

Originally Posted by Bob Parmenter

Never known anyone who successfully double flaired stainless, it's too brittle. Stainless is commonly done single flair with a JIC fitting at 37 degree rather than the 45 degree of the typical mild steel flair. Maybe that's why you had a problem earlier.

You buy the stainless steel tube annealled

Roadster,

I know that Speedway says their 304 S/S is double annealed but I had trouble trying to double flare my lines as received didn't work, the metal split as others has indicated. After annealing the tubing double flared with no problem. I see now that they say to single flare at 37˚ for AN fittings.

Steve,

I got my S/S brake lines from Speedway also and will have to check if they are seamed. I wasn't aware of not using seamed lines for brakes. Speedway sells these as brake lines.

(30 Min. later), Just got off the phone with Speedway, they double checked my past order and my brake lines were 304 seamless so I guess I'm ok.

Jack.

I talked to the guys at Inline Tube (where I bought my hydraulic flaring tool) and they said that when you cut the line with a tubing cutter or a cutoff wheel, you work harden the end of the tube.....anneal it after you cut it. He said that a hacksaw was gentle and might not work harden the tubing.....

Robot,

Hadn't thought of that, thanks for the info.

Jack.

Jack, it is still difficult to double flare annealed stuff.....I would start with a 5 ft stick, flare it, cut it off, flare it again, cut that off, flare it again.....sometimes I burned the entire piece without getting two good flares......learned new words however.

Sometimes, I got lucky and got two flares on the same tube to take....now, I'm scared to ever disconnect those lines.

Pre-flared tubing from the auto supply is much easier.....and cheaper, and better for your blood pressure.

mike

I do brakes all the time and prefer to do -AN fittings, you put them together and bleed the system - its that easy. When i do doubleflare (and i have a good tool) i have leaks that don't show up until you get close to system pressure and to fix you have to start all over.
I use a hack saw to make the cut, tubing cutter 'pinches' the line. I dress the cut with a file to square it and deburr the outside edge, a countersink to clean the inside edge. Getting these edges clean, square and consistant in metal thickness is very important.
I wouldn't doubleflare stainless (although i have never worked with that softer stainless) because the key to a doubleflare getting to seal is the 'crush' ability of proper brake line tubing - when doing the step of pushing the end down inside itself (doubling) you don't run the flaring tool down tight, you leave some 'crush' and i don't see the stainless having these properties. Again, i have never used it so i may be wrong.
I am a firm believer in -AN fittings, i can do a whole car and never have a leak.