Fuel leak L36 - NCRS Discussion Boards

Fuel leak L36

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • Rob M.
    NCRS IT Developer
    • January 1, 2004
    • 12738

    Fuel leak L36

    On my 1969 the fuel line between the fuel filter and the carburetor was no longer reliable and had to replaced. I ordered a new fuel line set from CC but not mounted it is leaking at the fuel filter fitting. Should there be some sort of O ring there or should it be fitter without some sort of gasket (metal on metal)?
    Rob.

    NCRS Dutch Chapter Founder & Board Member
    NCRS Software Developer
    C1, C2 and C3 Registry Developer
  • Edward B.
    Expired
    • March 29, 2013
    • 691

    #2
    Re: Fuel leak L36

    No o-ring, just metal to metal Rob. And yes, they leak. You have to really tighten the crap out of the repops. If you got stainless, forget it. It'll ALWAYS leak. But if you got plain steel, then the trick I used was to tighten, loosen, tighten, loosen and keep repeating until no leaks. Sometimes it takes several cycles but eventually, the two parts (the filter and the line) will mate to each other.

    Ed

    Comment

    • Michael H.
      Very Frequent User
      • December 1, 1987
      • 729

      #3
      Re: Fuel leak L36

      You may want to look for Flair Savers as they are made out of thin copper and would go between both steel lines and seal. I've had great success using these.

      Mike

      Comment

      • Rob M.
        NCRS IT Developer
        • January 1, 2004
        • 12738

        #4
        Re: Fuel leak L36

        Originally posted by Michael Hanley (12271)
        You may want to look for Flair Savers as they are made out of thin copper and would go between both steel lines and seal. I've had great success using these.

        Mike
        I had to look up what a flare save is using Google. I wonder where I could get these little gizmos?
        Rob.

        NCRS Dutch Chapter Founder & Board Member
        NCRS Software Developer
        C1, C2 and C3 Registry Developer

        Comment

        • Michael H.
          Very Frequent User
          • December 1, 1987
          • 729

          #5
          Re: Fuel leak L36

          Originally posted by Rob Musquetier (41157)
          I had to look up what a flare save is using Google. I wonder where I could get these little gizmos?
          Rob,

          I bought mine years ago they are used in the Aerospace/Aircraft industry.

          Mike

          Comment

          • John M.
            Expired
            • January 1, 1998
            • 813

            #6
            Re: Fuel leak L36

            Rob,
            You can get them from Grainger. Parker 45 deg. copper flare gaskets. They work nicely.

            Comment

            • Rob M.
              NCRS IT Developer
              • January 1, 2004
              • 12738

              #7
              Re: Fuel leak L36

              I'll see if I can buy a couple when I'm over in the States next week...
              Rob.

              NCRS Dutch Chapter Founder & Board Member
              NCRS Software Developer
              C1, C2 and C3 Registry Developer

              Comment

              • Gary C.
                Administrator
                • October 1, 1982
                • 17665

                #8
                Re: Fuel leak L36

                Rob, need to get you a tube of Fuel Save aircraft line sealant also.
                NCRS Texas Chapter
                https://www.ncrstexas.org/

                https://www.facebook.com/profile.php?id=61565408483631

                Comment

                • Steve G.
                  Expired
                  • November 24, 2014
                  • 411

                  #9
                  Re: Fuel leak L36

                  Tighten the flair nut as tight as you you are able with still being able to turn the line in the flare nut. Twist the filter back and forth on the line a few times, then tighten the rest of the way.

                  The twisting under pressure of the soft metal mating surfaces causes them to conform to one another.

                  Steve

                  Comment

                  • Terry B.
                    Very Frequent User
                    • August 31, 1999
                    • 607

                    #10
                    Re: Fuel leak L36

                    Unfortunately I over tighten my fuel line where it goes into the carb and had to take the carb to a machine shop to have the threads re- machined. There is a limit to the stress the fitting can take. Be sure everything is lined up correctly and do not over tighten. I hope the earlier given solutions work for you.
                    Terry Buchanan

                    Webmaster / Secretary - Heart of Ohio Chapter www.ncrs.org/hoo

                    Corvettes Owned:
                    1977 Coupe
                    1968 Convertible 427/390 (L-36) Chapter Top Flight 2007, Regional Top Flight 2010, National Top Flight 2011
                    2003 Electron Blue Coupe
                    2019 Torch Red Grand Sport Coupe

                    Comment

                    • Michael F.
                      Very Frequent User
                      • January 1, 1993
                      • 745

                      #11
                      Re: Fuel leak L36

                      use that white pipe tape for sealing
                      Michael


                      70 Mulsanne Blue LT-1
                      03 Electron Blue Z06

                      Comment

                      • John H.
                        Beyond Control Poster
                        • December 1, 1997
                        • 16513

                        #12
                        Re: Fuel leak L36

                        Originally posted by Michael Funk (22104)
                        use that white pipe tape for sealing
                        The white tape can shred while tightening the fitting and release crud to get in the needle-and-seats; I prefer using a light film of TFE pipe dope on the threads to reduce thread friction and reduce applied torque required to get the flare to seal (the threads don't seal anything).

                        Comment

                        • Joe L.
                          Beyond Control Poster
                          • February 1, 1988
                          • 43221

                          #13
                          Re: Fuel leak L36

                          Originally posted by Terry Buchanan (32872)
                          Unfortunately I over tighten my fuel line where it goes into the carb and had to take the carb to a machine shop to have the threads re- machined. There is a limit to the stress the fitting can take. Be sure everything is lined up correctly and do not over tighten. I hope the earlier given solutions work for you.
                          Terry-------

                          When tightening the tubing nut, you MUST hold rigid the fitting nut which threads into the carburetor. Use an open end wrench for this. You were lucky that you only damaged the threads. You could have fractured the float bowl thereby ruining the carburetor.
                          In Appreciation of John Hinckley

                          Comment

                          • Steve G.
                            Expired
                            • November 24, 2014
                            • 411

                            #14
                            Re: Fuel leak L36

                            Teflon tape or pipe dope of any kind does not belong on a straight thread fitting. As Joe said, anchoring the large nut when you tighten the smaller is critical.

                            But probably the biggest cause of damaged threads on that large nut and bowl, as well as other places where a gasket is used, is the failure to replace the gasket. It should be replaced every time it has been loosened.

                            The whole idea of a gasket is to compress and take the shape of the two surfaces the gasket is sealing. It does not decompress when you loosen it. So every time you re-tighten that nut the gasket has to try to compress further to achieve a seal. This takes more force the further you have to compress it. Eventually there is no compression left and you have to tighten it well beyond spec to achieve a seal.

                            Of course this leads to the smell of fuel when the car sits in the garage from the weeping at the nut so they wire back their heat risers and block the crossovers to stop the fuel from "percing".

                            Sorry, couldn't resist it

                            Steve

                            Comment

                            • Rob M.
                              NCRS IT Developer
                              • January 1, 2004
                              • 12738

                              #15
                              Re: Fuel leak L36

                              Originally posted by Steve Garner (60691)
                              Teflon tape or pipe dope of any kind does not belong on a straight thread fitting. As Joe said, anchoring the large nut when you tighten the smaller is critical.

                              But probably the biggest cause of damaged threads on that large nut and bowl, as well as other places where a gasket is used, is the failure to replace the gasket. It should be replaced every time it has been loosened.

                              The whole idea of a gasket is to compress and take the shape of the two surfaces the gasket is sealing. It does not decompress when you loosen it. So every time you re-tighten that nut the gasket has to try to compress further to achieve a seal. This takes more force the further you have to compress it. Eventually there is no compression left and you have to tighten it well beyond spec to achieve a seal.

                              Of course this leads to the smell of fuel when the car sits in the garage from the weeping at the nut so they wire back their heat risers and block the crossovers to stop the fuel from "percing".

                              Sorry, couldn't resist it

                              Steve
                              Ok, but I understood that there is no seal...
                              Rob.

                              NCRS Dutch Chapter Founder & Board Member
                              NCRS Software Developer
                              C1, C2 and C3 Registry Developer

                              Comment

                              Working...
                              Searching...Please wait.
                              An unexpected error was returned: 'Your submission could not be processed because you have logged in since the previous page was loaded.

                              Please push the back button and reload the previous window.'
                              An unexpected error was returned: 'Your submission could not be processed because the token has expired.

                              Please push the back button and reload the previous window.'
                              An internal error has occurred and the module cannot be displayed.
                              There are no results that meet this criteria.
                              Search Result for "|||"