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Subject: Stopping fuel leaks at fittings

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Jason (SWOR)    Posted 10-17-2018 at 11:05:57 [URL] [DELETE]        [Reply] [Email]  
  • Stopping fuel leaks at fittings
  • Hello folks... I haven't been around much because my dear old 8N has been down for some time now. I had reconstructive shoulder surgery and am just now getting back around to trying to revive it. I could use your advice, if you have the time.

    When I parked it, it had a brand new carb and fuel line but the fuel line (purchased from NAPA) leaked both at the fuel bowl under the tank and the carb. I know it's easy to over-tighten those flange fittings, so bought another one and tried having a friend do it, same result. We put enough fuel in it to park it somewhat out of the weather and it has been sitting since.

    I ordered a new fuel bowl for under the tank and a matching pre-shaped fuel line from a mail order source. I am getting ready to install all of that but am wondering about if there is any compound or fuel safe tape useful for the threaded portions of these fittings? Or, is it best practice just to mate them fitting to fitting?

    Thank you for your time and have a wonderful week, my best regards to you all and thank you for your time...

    Bandon, Oregon

    Jason (SWOR)    Posted 10-17-2018 at 18:42:22 [URL] [DELETE]        [Reply] [Email]  
  • Re: Stopping fuel leaks at fittings
  • Thanks to all! I am grateful for the input and guidance. I need to reprint that 75 tips guide and then MEMORIZE IT. :)

    So, what I am taking away from this is that I bought the right parts, try to avoid using sealant of any kind, be careful with the flare wrench and hope I do it just right, slowly and very carefully.

    At this point I will try to hand tighten the ends, then proceed very carefully with a flare wrench, which is 7/16 and I just purchased today and just verified fit exactly correct, thanks to some of the advice. :)

    Will be doing this Sunday, and looking forward to hearing the engine running again. If I can get it running consistently again, it will have a glorious future, according to my wife (who directly golds the purse strings!)!

    As far as the shoulder goes, well, long story short (trust me, this is short for me!), I am 43 and my wife claims I was too young to "not be able to do things!", so we went ahead with the surgery. The sickening part was, following the reconstruction (which was every bit as painful as they said it would be, in spite of my super hero attitude), I heard nothing but terrible comments from people who claimed it was the "worst decision of my life". I heard this almost daily and from complete strangers out in public all the time. You folks here are the first one to encourage me. I just got cleared to change the oil on the car, so I figured this was an easy enough process and would give it a go. It is a long recovery, but I am hopeful! Thank you all very much for the kind words.

    I'll keep you posted and let you know if I am all thumbs and overtighten and need to place another order. :)

    You all be good in your neck of the woods and thank you all again!

    Bandon, Oregon

    Tim Daley(MI)    Posted 10-17-2018 at 16:26:41 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Stopping fuel leaks at fittings
  • HiYa Jason-
    Healing can be a long process. Just do what the doctor ordered.

    For the Ford Tractor fuel system, best to use a part made for the job -see LINK below with the fuel line, exactly pre-bent steel line with correct fittings. Brake and fuel lines use a special thread size - 7/16-24. Many fellas muck them up by using the wrong tap or thread die to "fix" a part with and all it does is cross thread with the wrong pitch which in turn causes leaks. As mentioned, forget Teflon Tape or plumbing compound. You don't want to be guessing if fuel will leak or not do you? Always start the fittings by hand so you can get the 'feel' whether they are fastening correctly. Once you cross-thread a component, it is almost impossible to correct. The steel line use steel fittings, the sediment bulb uses a pewter or aluminum base. Steel is harder and thus it is the softer material that will get cross-threaded. Installation works best by using two hands. One to gently wiggle the line as you work to ensure the flare is seating properly and aligning it squarely. Use the the other hand to slowly screw the fitting in. Never force it. If the line gets bent at the fitting and you try to straighten it, it can be a problem for leaks to occur so be gentle. On the Sediment Bulb Assembly, the line connects to the output port. The other end inserts into the brass elbow on the carb. Use a 7/6" Flare Nut Wrench to do the final tightening and do not overtighten. Often times leaks are the result of the Sediment Bulb Valve Stem. There is a rubber seal, some new units use vinyl, on the stem that will eventually wear out, get torn, and thus leak. Sometimes leaks are coming from it and misdiagnosed as being a bad connection elsewhere. The valve stem is a $5 part. It is the only wear part on the assembly. You don't need to buy a whole new assembly when repairing them. The stem uses the same size thread into the bulb base as the fuel line. Get a new valve stem and a new cork gasket and brass screen for the jar when doing PM. The stem is p/n APN-9194 and comes with a new knurled knob, 8-32 screw, and #8 star lockwasher. I always put a dab of Loctite on the screw to ensure it never comes off the assembly in the field. You never need to take it off either until the next valve stem replacement. Then there is a fine thread sealant product called E-SEAL made by GASOILA. I use it ONLY on the sediment bulb screwing into the gas tank. The tank and all parts must be dry when you apply it. Assemble and let stand for few days before using. I only use it because I had once bought a cheap aftermarket assembly with the WRONG NPT threads on it and it mucked up my gas tank inlet. Not everyone needs to use a sealant on the bulb to the tank. I will also use it when I work on someone's tractor and they want a new bulb installed. I NEVER use anything on fuel lines elsewhere. Always use the correct 1/4" steel brake/fuel lines. Never use copper, nylon, plastic, or aluminum. This procedure is what I've developed over my years working on N's.




    Tim Daley(MI)

    Bruce (VA)    Posted 10-17-2018 at 12:39:44 [URL] [DELETE]        [Reply] [Email]  
  • Re: Stopping fuel leaks at fittings
  • It's a flare fitting; it seals on the flare. So you are not only wasting your time w/ Teflon tape, if a piece of it gets in the carb, you will be walking home.

    Do NOT use any tool to start the connection. Get it started w/ your fingers. Once you have it finger tight on both ends, then & only then, get out your flare wrench.

    See tip # 56

    K.LaRue-VA    Posted 10-17-2018 at 14:00:32 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Stopping fuel leaks at fittings
  • Everything Bruce wrote and:
    Even with pre-formed lines or reinstalling old lines, make sure the flare at both ends is formed right and not cracked. Make sure area each end seals is clean. Start the fitting at one end, then tweak the bends slightly so the other flared end is centered and square to the hole. Both nuts need to start and go most of the way with just fingers. Get them snug and the flares should seal. Snug is fine, no need to be a gorilla with flare fittings. Once in a while I get a drip and have to go back and tighten one end a little.

    Rustyal    Posted 10-17-2018 at 11:53:00 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Stopping fuel leaks at fittings
  • You can use Teflon tape on the threads. Hope you are using a line wrench. My wife had her shoulder rebuilt with great results. Best wishes.

    K.LaRue-VA    Posted 10-17-2018 at 14:14:51 [URL] [DELETE]        [Reply] [No Email]  
  • Re: Stopping fuel leaks at fittings
  • The fuel valve assembly goes into the tank with a tapered fuel thread that should not need anything to seal. Same for the threads where the fuel elbow screws in the carb. However, old tapered threads may be deformed or scored, so I use a sealant. Not the white teflon stuff. That is for water lines. For fuel lines get the (usually yellow) tape or liquid thread sealant for gas/fuel lines. The hardware stores should have the different types of sealants together, or they may have the fuel line sealant near the gas water heater or gas fireplace installation kits.

    When applying sealant to tapered threads, leave the first male thread that will go into the carb or tank completely clean. Cover the rest of the threads with sealant. Start the fitting by hand then start snugging with a wrench until the fitting is pointing the right way. It is hard to describe how tight a tapered thread needs to be, but if you turn past where the fitting needs to be you cannot back up or it will certainly leak. If turned past the correct location, they have to be tightened until they come around again.

    To repeat what Bruce said, do not apply any sealant to the straight threads on captive nuts that secure flare tubing into flare fittings.

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