Seating brake line fittings

[Blitzed]

Hi All,

73 240Z

Hoping someone has a fix. Replaced all of my hard brake lines from Classic tube and have an issue with one line. The tube flare will not seat. The line is seeping brake (very little but frustrating) fluid from the hole in the fitting, threads on the fitting are dry.

Removed and adjusted the line so there is zero tension on either ends of the brake line, finger tighten the fittings flush before final torque with a wrench. Did the 1/2" turn lose and and tighten over and over again, still seeping. 

The fluid seeps cold or after driven.

Leaking from the front brake line from the master cylinder to the safety switch block below the master.  Leaking line connection is the  inverted fitting bottom of the safety switch. 

Merry Christmas and a Healthy 2022. 

[Patcon]

Post some pictures. Maybe take some pictures of the offending fitting on the end of the brake line and the flare. The more the better

[Zed Head]

Have you examined the cone that the fitting seats on?  It might need a hone.

[siteunseen]

Maybe use this if all else fails.

[Blitzed]

Hi All,

Zed Head the fitting flare seeping would be below number four on the diagram. Is their a honing tool I could purchase? 

As mentioned, it's not the fitting flare threads that a seeping fluid is seeping from the hole running down the tube. So the tape will not work. 

Thank you.

 

[Zed Head]

If you have a spare brake part around and a flared tube end it might help you to just pull the threaded portion back and stick the tube in to the hole, just to get a feel for how they seal.  The threaded portion's sole purpose is to apply pressure on the bell edges of the flared tube end, pressing it down on to the cone in the middle of the device, whether it's a brake cylinder or a caliper or the pressure differential switch.  There are only two surfaces that need to be smooth, clean, and crack-free - a small ring around the inside of the flare, and a small ring where the inside of the flare contacts the cone.  You can take a bright light and a magnifying glass and examine them closely and you'll get a good idea beforehand if they're going to seal or not.  All it takes is grain of sand, or a metal shaving, to get trapped there and you can have a leak.  Or even just a scratch or a crack.

Once the fluid gets in to the void at the end of the fitting it can easily leak past the fitting end and out of the hole since the fitting end is designed for force not sealing.  The fitting is just a clamping mechanism.

Anyway, a bunch of words to say take a close look at the actual fluid sealing surfaces.

[Patcon]

Are these Stainless lines?

I agree with Zed, look for a crack or other flaw in the flare and cone

[Blitzed]

Thanks, will check and report back. 

[Yarb]

I have the same exact problem on the opposite end of the MC line. I’ll take mine off and look for a crack as well. Anyone have any replacement lines for this connection?

[Zed Head]

I had good luck at the local parts store.  They typically have a wall loaded with precut, prefitted lines of various makes.  Take the old one in, maybe with a wire or string you used to get the unbent length and you can walk out with a piece that just needs a few bends to bolt right in, professionally flared.

[Blitzed]

Classic Tube or Datsun Z (they buy the kit from CT). You have to buy the complete kit $300.0 + 6-8 weeks. If you need one or two need to make them yourself. 

[Patcon]

If I thought they shipped me a cracked line, I would expect them, to make it right!