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Subject: New gas leak

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Frank (WNY)    Posted 06-08-2020 at 16:22:19 [URL] [DELETE]        [Reply] [Email]  
  • New gas leak
  • I installed a new fuel valve and sediment bowl without the bowl. With the valve closed, I saw fuel dripping from the hole on the bottom of the assembly. I then swapped the stem from the old valve it looks like it stopped. I hooked a new fuel line to the side of the valve and tightened it. I opened the valve and the bowl filled without leaking around the top of the bowl, but there was a slow leak on the flare nut on the fuel line. I tightened it some more and it seemed to stop it. With no more leaks I filled the tank about quarter full and ran the tractor for about an hour using a box blade to rip up some dirt. When I went to shutoff the valve gas was dripping from the flare fitting. I put a wrench on it and it feels like it loosened a little. I tightened it again, but wit the valve open it still leaks. I donít want to break anything by over tightening it. AnybodyHey have any ideas about how to fix this. It is a 50 8N. Thanks.

    Frank (WNY)    Posted 06-09-2020 at 16:12:52 [URL] [DELETE]        [Reply] [Email]  
  • Re: New gas leak
  • So, I finally gave up on the new fuel line, and put the original, bent up, beat up line in that I bought the tractor with. Looks awful, but after about an hour of driving around, no leaks yet. The only new part that is in it, is the fuel valve/sediment bowl with the old stem.

    Tim Daley(MI)    Posted 06-10-2020 at 05:17:17 [URL] [DELETE]        [Reply] [No Email]  
  • Re: New gas leak
  • Have you tried contacting the place where you bought the fuel line and asked them? Reliable sources will look into it and/or replace the defective part. I've had defective parts made in Cheena replaced before by Steiner, Carpenter, & Barkley [sounds like a legal firm ; > )] and their suppliers fixed the defects. A very good possibility with the fuel line is the 1/4" tubing isn't flared enough to seat correctly. If you have a Flaring Tool Kit you could try to flare the end more or cut the end off and re-flare it altogether and see if that works.

    Tim Daley(MI)

    Frank (WNY)    Posted 06-10-2020 at 06:03:30 [URL] [DELETE]        [Reply] [Email]  
  • Re: New gas leak
  • Hi Tim, I bought the parts from just8nís last fall when I discovered the leaking valve which I also bought from them 2 years earlier. I usually buy everything for this tractor from them and have never had any problems before with either parts or service. Now that I have figured out whatís happened i will contact them. I was just curious if anyone else had seen this problem with the valve. If nothing else in the fuel system is not leaking and the carb float is working properly you wonít notice the valve leak.
    Thanks, Frank

    Tim Daley(MI)    Posted 06-10-2020 at 06:19:19 [URL] [DELETE]        [Reply] [No Email]  
  • Re: New gas leak
  • If your Bulb Assembly leaks when the glass bowl is off and Shut-Off Valve closed, the problem is in the valve stem. Could try a different supplier -look for the TISCO brand. Your carb should be fine for now, you can always rebuild it if it's been a while once you fix leaking issue. If no gas evident in carb air intake throat when rubber hose removed, float should be OK too.

    Tim Daley(MI)

    Frank (WNY)    Posted 06-10-2020 at 10:34:04 [URL] [DELETE]        [Reply] [Email]  
  • Re: New gas leak
  • The new one that came from just8nís is a Sparex brand. I was able to get the leak to stop when I took the valve stem from the old one (that it was leaking in) and put it in the new one. Where would I buy TISCO brand?

    Tim Daley(MI)    Posted 06-09-2020 at 07:36:18 [URL] [DELETE]        [Reply] [No Email]  
  • Re: New gas leak
  • HiYa Frank-
    I know you know most of this already but I will post for those who don't and to ensure the info gets archived for future use. You don't want any fuel leaks; that is a recipe for disaster. Don't try band-aid/quick fix things to use like pipe dope, electrical tape, or Teflon Tape. They never work anyway. Fix the problem right.

    We never used to have issues with the Fuel Sediment Bulb Assemblies until they started coming from Cheena. Even India and Brazil made good ones. I've had boogered up threads on main intake, vinyl valve seat gaskets (they'll leak), and wrong threads on fuel lines. The major issue with the sediment bulb is when the seal in the valve stem wears out, and they will, and the leaking starts. It is best to never remove the Bulb Assembly from the tank; only if you need to clean the internal screen. Replace the Valve Stem Assembly when it is time. Replacing the Valve Stem Assembly, p/n APN-9194, is usually all that is needed -it is the ONLY wear part in the Bulb. Now, I highly recommend you apply a dab of Theadlocking Material on the 8-32 screw that secures the Valve Knob onto the stem with. New units tend to loosen in the field, fall off, and get lost forever. You never have to remove the knob so it won't be a hindrance and you get a new screw and knob with the new stem.

    One of the other major problems also with the new Bulbs is the fuel line threads. The Threads on the Bulb for the unit AND the brass elbow carb inlet are special threads designed for fuel and brake lines. The thread size is 7-16-24 UNS. The fuel line is 1/4 steel. New Bulbs may use metric or just wrong sizes and guys too will try to do their own thread chasing with the wrong sizes. Always use your fingers to start the flare nut inserts and use your other fingers to help guide the fuel line. The line tension can bind and hinder proper insertion. Cross threading is the major cause of stripping the fuel line inlet threads and thus will leak. Always use a 7/16" Flare Nut Wrench and never use pliers, channel locks, an adjustable wrench, or vise grips. Rounding off the flare nuts will occur and you never want that. Always use the OEM cork gasket on the glass bowl -never rubber or plastic. When cleaning bowl and screen, replace with a new cork gasket. Be sure to remove any old cork on glass rim and inside Bulb Assembly. Take a sheet of medium grit sandpaper, place it on the table, lightly run glass bowl rim around to remove old cork and gum.

    The main causes of fuel leaks are #1, #2, and #3 sediment bulb valve stem. The valve stem is the only working part in the system and it will wear out the seal on it and leak. It is OEM Ford part number APN-9194 and costs $6-$8 at reputable dealers like just8Ns.com. If you pay anymore than that then they are ripping you off. #6 failure is from worn, cross threaded, or wrong fuel line fittings at sediment bulb inlet and/or at brass elbow carb inlet. Use the correct OEM-type fuel line, made exact and pre bent too. Using plastic, copper, nylon, or rubber is NOT recommended. Leak #4 comes when fellas leave the fuel valve knob on when they shut down the tractor. If seal is getting bad, it will leak if left ON and/or when opened. Leak #5 can be caused by backed up vacuum in stem if gas tank vent is plugged, and leak #7 can be caused for same reason if brass fuel line inlet at carb is plugged at the filter.







    -There are 3 fuel filter screens in the OEM N-Tractor system design You DO NOT need to add your own external type filter. The OEM fuel screen system works just fine. If the first screen, up inside the Bulb Assembly inside the gas tank gets plugged with dirt, it's time to pull the gas tank and clean it out, and possibly recoat it. The brass elbow screen at the carb is often neglected or forgotten. When it gets plugged, it can cause carb fuel flow issues.



    Tim Daley(MI)

    Frank (WNY)    Posted 06-09-2020 at 08:39:29 [URL] [DELETE]        [Reply] [Email]  
  • Re: New gas leak
  • Hi Tim, my original problem was a slow drip from the tank through the valve into the bowl with the valve turned off. I bought a new assembly from just8nís and installed it. That one wasnít any better and still leaked through the valve. I swapped the stem from the old assembly and that stopped the leak. I bought a new fuel line along with the valve installed it and didnít see any leaks. The tank had about 2 gallons in it and drove around with it. I filled the tank with another 4 gallons drove some more and when I went to shut off the valve, thatís when I saw the gas leaking from the flare fitting under the flare nut at the valve outlet.

    K.LaRue-VA    Posted 06-09-2020 at 07:30:45 [URL] [DELETE]        [Reply] [No Email]  
  • Re: New gas leak
  • 1 - Plumbing is my least favorite repair.
    2 - New always seals best to new.
    3 - Make sure you can see exactly where the leak is coming from. A leak near the top of anything can run just about anywhere before it drips and may even seem to defy gravity.
    4 - Tapered threads at tank and valve assembly should seal with no sealant required. The threads on both parts need to be completely clean for that to work. I usually use some sealant for fuel/gas systems. White teflon is for water and won't work for fuel.
    5 - Flare fittings need to be clean and assembled straight. If they still won't seal with moderate tightness, take apart and look for a crack where the metal was folded to make the flare. Look at the seat area and make sure that is clean and smooth. If flare or seat is cracked, corroded, or dented by assembling crooked, it's junk.
    6 - Shaft for valve should have a packing nut. Those often come loose in shipping or are just assembled loose. Packing nut should be tight enough to seal, but valve should still turn easy.
    7 - Use a new seal for the glass fuel bowl. There are some that seem to seal better than the original plain cork, but the cork ones have worked for many years.

    Frank (WNY)    Posted 06-09-2020 at 08:19:06 [URL] [DELETE]        [Reply] [Email]  
  • Re: New gas leak
  • The leak is coming right under the threads where the flare fitting enters the valve assembly. I just removed the line this morning and the end that goes into the elbow at the carb looks smooth and shiny. The end that is leaking looks a little rough. I will try to look at the seat next to see how that is. I used gasoila to seal the assembly to the tank and everything is dry.

    Bruce(VA)    Posted 06-09-2020 at 06:21:43 [URL] [DELETE]        [Reply] [Email]  
  • Re: New gas leak
  • See tip # 56.

    Where did you get the fitting?

    Frank (WNY)    Posted 06-09-2020 at 08:10:22 [URL] [DELETE]        [Reply] [Email]  
  • Re: New gas leak
  • I bought the new valve and bowl assembly and the fuel line from Just 8Nís. The leak is at the valve end of the fuel line. The fuel inlet elbow is new and not leaking on that end. Thanks

    Mike W    Posted 06-09-2020 at 12:20:30 [URL] [DELETE]        [Reply] [No Email]  
  • Re: New gas leak
  • Sometimes flared line fittings just won't quit leaking. Since they're often made of softer metals continued tightening will eventually break something.
    I know they say we should never do this, but in the real world where the machine has to get its work done, we develop techniques that annoy perfectionists.
    Shut off the valve, unscrew the flare nut on the line, wrap a few turns of Teflon tape around the line, carefully thread the nut back in. Tighten snugly and check to see that your leak has stopped.

    Frank (WNY)    Posted 06-09-2020 at 13:20:13 [URL] [DELETE]        [Reply] [Email]  
  • Re: New gas leak
  • Thanks for the suggestion Mike. I am trying a few other tests to determine if the leak comes from the fuel line or the valve assembly. I havenít seen any gas coming from around the line just from the threads. I read where regular Teflon tape is dissolved by gas and there is a type made just for gas. I would prefer to see if I can identify where the problem is and then figure out how to best fix it.

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