Pre-fab tube with steel flare nut fitting leaking

[Pete Deering]

I am repairing some steel tubing and I am using flare fitting and brass union (coupling) too joint the lines.
I purchase pre-fab brake tube with flare fitting that are steel and also the mating brass union.

Problem I am having the steel fitting are leaking at the connection.

Has anyone else have problems with leaking fitting?
What did you Do too get the fitting too seal?

I am now replacing those fitting with brass fitting. what I found out, is that steel and stainless steel lines have a tendency too not seal and leak. They make and sell Copper flare washer for this problem, but will not get them for a few weeks.

Copper sealing washer are common used for the flex hose banjo fitting and the brake caliper . Supplied by the caliper manufacturer or re-builder.

 

[C420sailor]

You using the right type of flare? SAE/inverted/double?

Makes me wonder if you’re using a fitting designed for a bubble flare

 

[410Fortune]

if you are good at making flares and have the correct size line and a good flare, maybe try a little tighter

You can take it apart and have a close look, usually you can see the "wear" marks from when you tighten it down, see whats going wrong

Flare must be made properly and with care and precision. A file is needed to make sure there are no sharp edges or burrs, the depth you set the tool at is extremely important. No room for error here

 

[Pete Deering]

You using the right type of flare? SAE/inverted/double?

Makes me wonder if you’re using a fitting designed for a bubble flare

Right flare

 

[Pete Deering]

if you are good at making flares and have the correct size line and a good flare, maybe try a little tighter

You can take it apart and have a close look, usually you can see the "wear" marks from when you tighten it down, see whats going wrong

Flare must be made properly and with care and precision. A file is needed to make sure there are no sharp edges or burrs, the depth you set the tool at is extremely important. No room for error here

I replace the steel fitting with a brass fitting and the connection seals.

 

[J_C]

I'm not quite clear on what the situation is. Can you elaborate?

You bought line that is pre-flared and it is leaking at the coupling?

If you are making new flares and they leak, it may be a sign the flares are not well formed.

I would hope that your steel couplers were well formed, but if using brass gets the job done, is this the accepted solution?

Personally, I would just run a new line end to end instead of repairing a segment... unless the break was caused by road debris, otherwise I figure that by the time one section is rusting through, the rest may be headed that way too. Another exception would be if the line nut is rust seized and mangles the line when you try to get it off, but since our lines weren't coated, by the time the nut rusted that much, my lines had too.

 

[Astrobuf]

I am repairing some steel tubing and I am using flare fitting and coupling too joint the lines.
I purchase brake lines with flare fitting that are steel.

Problem I am having the steel fitting are leaking.

Has anyone else have problems with leaking fitting?
What did you Do too get the fitting too seal?

I am now replacing those fitting with brass fitting. what I found out, is that steel and stainless steel lines have a tendency too not seal and leak. They make and sell flare washer for this problem, but will not get them for a few weeks.

Not sure what you mean by flare washers. I suspect you mean the brass ferrules that slide over the brake tubing.

IT IS ILLEGAL TO USE THIS ON A BRAKE LINE! IT IS HIGHLY DANGEROUS AND LIKELY TO LEAD TO BRAKE FAILURE.

I'm not sure what your problem with steel brake lines and flares is. Ive done this succesfully for 40 years. I'm guessing you either bought the wrong coupling (there arec3 or 4 types) or perhaps did not form the flare correctly. To do this properly, to start, you need to use a double flare tool. It is very important to make a smooth centered flare. If you do not know how to do this correctly, hire someone else to do so lest you kill yourself and likely others.

Astrobuf

 

[J_C]

^ I had trouble making the double flares using the crappy loaner tool from either Autozone or Advance Auto. It couldn't hold the tubing still without excessively mashing it, IIRC. Bought one from Eastwood and was making great flares right away. Still no leaks from them.

 

[Astrobuf]

^ I had trouble making the double flares using the crappy loaner tool from either Autozone or Advance Auto. It couldn't hold the tubing still without excessively mashing it, IIRC. Bought one from Eastwood and was making great flares right away. Still no leaks from them.

"A man with poor tools pays twice"

 

[J_C]

"A man with poor tools pays twice"

Not so much in this case. Over time I've had a fair amount of occasions to use the parts stores' loaner tools and they worked fine, but the flare tool in particular... most seem to offer the butterfly clamp style which is just not the best design for the job.

Plus it wasn't paying twice, loaner tools are refunded. Despite this, I still advocate loaner tools instead of buying it if someone anticipates only one use, except in this one case of a flaring tool, then it depends on the tool design.

 

[BrettS.]

^ I had trouble making the double flares using the crappy loaner tool from either Autozone or Advance Auto. It couldn't hold the tubing still without excessively mashing it, IIRC. Bought one from Eastwood and was making great flares right away. Still no leaks from them.

Those rental store flare tools are junk. I bought an Eastwood kit too and it works great. I use to stuggle with leaking flares unitl I started using the proper tool and haven't had one leak yet. Also I only use copper nickel brake lines. They are easier to bend, easier to flare, and never rust.

 

[410Fortune]

its a metaphor, you can pay with money or you can pay with your life

If you are making brake lines chances are you will need to make them again
a good flare tool is not expensive, by comparison speaking

 

[J5hort]

Sounds like a flare not correctly seating. They can be malformed and will tend to leak. I have used rental and purchased flare tools. There is a bit of an art to it and you need to take your time to make sure the double flare is correct. While I agree that tool quality makes a difference in the process, a professional tool is not required to do the job (not trying to call out tool snobs). Done right with a loaner tool can yield great results.

 

[J_C]

its a metaphor, you can pay with money or you can pay with your life

If you are making brake lines chances are you will need to make them again
a good flare tool is not expensive, by comparison speaking

I took it as the other metaphor of buying junk tools, then having to replace them with better tools, or you mess up the job and then it's more work, but that doesn't seem to apply in this case unless the brake line was cut with so little slack that it can't be reflared.

Then there's the other possibility, that the poor flare causes the installer to torque the nut down more to make it seal, then it's harder to get off later, especially if rusted.