Stainless Steel Brake Line Fitting Leak

[David63]

Has anyone else had difficulty getting new stainless steel brake line fitting to seal without leaking? How tight should they be cranked down?

Never had a problem with regular steel brake line fitting leaks. Maybe I should just order some steel lines.

 

[Jason72Bronco]

When I did mine (all new SS lines, ends, junctions and fittings), I had a couple of places that seeped under pressure. Just a few drips every time I drove around. One that I remember was the junction over the diff. Another was into an adjustable proportioning valve I installed. In both cases, I loosened them a bit (not removed all the way, a few turns) and made super-sure the line going into the junction was as "straight in" as possible while tightening, even holding it straight in while I tightened. This to make sure the flare was as seated as uniform as possible inside the fitting. It has been fine for three years or so now. (Of course, you have to bleed again after you do this.)

I had some similar seepage installing new SS lines on another project (my 53 chevy) just past weekend, even though it was as straight-in as could be. So I just had to carefully tighten it a bit more--more than I really like to. I hate to over tighten brake lines because we all know how easy they are to strip when loosening, but it worked and hopefully I won't have to try and remove them in a long, long time.

 

[SteveL]

It's the nature of the beast going with ss brake lines. I've seen enough of these posts to keep me from going stainless when redoing my brake system.

 

[MarsChariot]

I had leaks at at least two fittings when going to stainless. Just cranking it tighter did not solve anything. What did the trick was to back off and re-tighten, maybe one or two times. Eventually it sealed just fine.

 

[Glass Pony]

It's the nature of the beast going with ss brake lines. I've seen enough of these posts to keep me from going stainless when redoing my brake system.

Me too. I've worked enough with stainless pipe threads also. It is "the nature of the beast."

 

[broncochevy]

Stainless needs to be flared perfect and super tight. And then 20% of mine leaked and needed attention or to be flared again. X2 on the not using as for my future builds.

 

[bronconut73]

I have heard that with the SS lines you often have to do what our buddy here suggested.
Loosen and re-seat the fitting a few times. Each time you are better shaping the seat.

 

[Bronco4x4]

I think this thread has confirmed my decision to go with nickle copper brake line.
AL

 

[rydog1130]

x3.....Stainless is harder than nickel copper lines. I had the same issues and I consulted a guy who knows a lot about brakes and heres the fix.... crank them down tight as possible, then back them off a bit, then crank them back down again....it takes 2-3 times of doing this to get that flare to seat correctly

 

[pipeline010]

I have heard that with the SS lines you often have to do what our buddy here suggested.
Loosen and re-seat the fitting a few times. Each time you are better shaping the seat.

DO NOT OVERTIGHTEN.

Once they seat, they seat. Back off, screw in, back off, screw in...test...repeat.

When I did mine in the rear they leaked on both sides..I went at them gently with a flare wrench and once I got them seated properly I never had to look at them again. That was many months ago. Whole process took only about 15 minutes.

Don't shy away from SS lines. They look great and once they hook up properly they won't leak. Tighter is not necessarily going to get you there, just take it easy back and forth.

 

[Broncobowsher]

Are you having problems with double flare, single flare, or AN fittings?
The AN fittings have worked fine for me.

 

[jagbucket]

i had to spend around $250 to get a tool that would handle ss, the cheaper flaring tools are just not strong enough. draw back is that it is vise mounted

 

[JB Fab]

i had to spend around $250 to get a tool that would handle ss, the cheaper flaring tools are just not strong enough. draw back is that it is vise mounted

What he said

 

[73azbronco]

Put a touch of oil on face of flare fitting, use a flare nut wrench, crank it tight, losen, tight, losen crank it again, seems to work so far.

But I'm not using stainless again ever. Nickel copper works great, almost bends for corners without needing tool to bend and keep it from collapsing.

 

[johnbeck]

Does everyone assemble stainless to stainless, and stainless to aluminum fittings dry? Will a lubricant allow the fittings to get too tight? Thanks