Brake line repairs

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  • Witsend
    Banned
    • Nov 2012
    • 2942

    Brake line repairs

    I have always double flared brake lines with my Snap On Blue Point Double Flaring tool and used unions where I have joined new lines together as well as where I have cut out a rotted section to join the new to a solid part of the remaining old line, but I have trouble getting a quality leak free double flare off the old sections of line, and I have to always have to toque the tube nuts to the unions more than I feel comfortable having to do in order to get unions to seal , and I am starting to beleive having to torque the tube nuts near the point of union thread failure for things to seal be anymore safe than joining with compression fittings, especially for the time spent . I think on the rear brake lines I am only going to join new to new with unions and start joining the old to new with compression fittings.
  • greasybob
    Senior Member
    • May 2008
    • 1590

    #2
    I don't think that compression fittings are a good idea for brake lines. If you do a lot of brake line work I have two ideas to make life easier. Get a quality hydraulic flaring tool such as the Mastercool Hydraulic Flaring Tool Set. 2nd, use the NiCop tubing. Much easier to work with than steel tubing and won't rust. I rarely look for a good starting point in the existing line, replace the whole thing and prevent a come back.

    Comment

    • Crusty
      Senior Member
      • Dec 2007
      • 2450

      #3
      Do NOT use compression fittings.....
      There is a ten hour discussion on that point-!!
      Just don't do it.

      Try this......
      When you start your flare and bubble the line normally thats fine.
      when you take the insert out to fold thr line back down, dont torque that quite so hard. Sure fold it down to make your double flare but stop a half turn or a turn sooner so you have the correct shape but the metal isn't compressed where it can't " give" anymore.
      Allow the tube nut and the inverted flare of the union to "compress" the double flare that last little bit so they can shape themselves together.
      Its a judgement thing and takes practice and doesn't work 100% of the time but it still be a strong junction and youll have fewer seapage problems.
      Up here rusty lines and corroded fittings are a normal condition.
      HTH

      Comment

      • chaskuss
        Senior Member
        • Dec 2009
        • 192

        #4
        Are you fond of chrome jewelry?

        Make a brake repair using compression fittings and you will get some up close, personal and very unwanted attention from the NTSB; if there is ever a failure, accident or you are reported by another shop. Beyond the fact that it's unsafe, it's also illegal. Unless that is, you are looking for free room and board at Levenworth. Compression coupling are not designed to function at the maximum pressures that automotive brake systems can generate.
        Charlie

        Comment

        • Witsend
          Banned
          • Nov 2012
          • 2942

          #5
          I have never ever ever used compression fittings , but I have Horse Shoed the rear brake ports together at the proportioning valve on old Toyoda Corrodas that I felt were too rusty to safely support them on jack stands to risk my own life under.(Just to get a pedal to get it to junk yard)
          Last edited by Witsend; 03-22-2018, 09:53 PM.

          Comment

          • Witsend
            Banned
            • Nov 2012
            • 2942

            #6
            Not out of the woods yet with bubble flaring

            I hate replacing rusty brake lines and double flaring metal tubing with mixed results. I always bought ready made metric bubble flared tubes and cut them in two and double flared cut side after slipping a regular 3/16" tube nut on and joined to a union and lines I fabricated. The 3/16" tubing worked fine for creating metric 4.75mm bubble fittings. I recently ran into larger metric bubble fittings on the next size up metric line (6mm). I can get the larger metric tube nuts to fit over(albeit snuggly ) over 1/4"metal tubing but the bubble flare didn't form correctly right on the 1/4" line. Seems the auto parts stores want to charge you twice as much for 25'roll of 6mm tubing (.236") versus the 1/4" (.250") tubing. The 6mm tube nuts fit over the 1/4" tubes, but obviously the result isn't too pretty trying to get by metric bubble flaring the cheaper 1/4" tubing I had left over from another job instead of purchasing a new roll of 6mm tubing.
            Attached Files

            Comment

            • Witsend
              Banned
              • Nov 2012
              • 2942

              #7
              Stores around here don't stock a roll of the 6mm tubing to fabricate from, so I just bought the longest length ready made ones and try to duplicate the old bends by hand the best I can do using zip ties to keep it all together and it resembles a porcupine or a modern art "Rigcasso" and then after cutting , reaming and deburring did my first correct metric 6mm bubble flare on an actual 6mm tube with my new hydraulic flaring kit, so yeah this thing works better with way less physical effort and more consistent results than what I was using before.
              Attached Files
              Last edited by Witsend; 03-22-2018, 09:41 PM.

              Comment

              • chaskuss
                Senior Member
                • Dec 2009
                • 192

                #8
                Thanks for the update & photos

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