how do you fix a gas leak?

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TBones12
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how do you fix a gas leak?

Post by TBones12 » Mon Sep 07, 2020 10:23 am

Would someone please tell me how to stop the gas valve from leaking? My other T also leaks but I live with that one.
The leak is from the top. I tried taking it apart and putting soap on it and some other stuff they say airplanes us on gas valves (I think.)
Thank you in advance, Bob
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Norman Kling
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Re: how do you fix a gas leak?

Post by Norman Kling » Mon Sep 07, 2020 10:40 am

The original valve was on the sediment bulb under the gas tank. Your valve is after market. Many owners place the valve next to the carburetor so they don't have to crawl under the car to shut off the gas. Since your valve is non-stock, why not just buy another one from a vendor? With the valve you have, you will still need to crawl under the car if you want to remove the carburetor, but you can get an in line valve which can be detached from the carburetor without having to remove the valve with the carburetor. I don't know yow you would stop your valve from leaking.
Norm

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Re: how do you fix a gas leak?

Post by Mark Gregush » Mon Sep 07, 2020 10:44 am

I installed a ball type inline shut off. Not original looking but would rather have one that worked then worry about appearances. In my OP, the modern type brass used to make the valves like you are using is too hard and makes hard to get a seal plus they are not real user friendly to open and close. If you want to keep the one you have you can try lapping it in with toothpaste or Timesaver then relube. Are you sure it is not leaking where it is screwed into the carb? Looks like it is installed really deep. Normally would expect to see threads showing, not seated all the way to the flats.
I know the voices aren't real but damn they have some good ideas! :shock:

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Re: how do you fix a gas leak?

Post by RajoRacer » Mon Sep 07, 2020 10:58 am

Astute observation Mark - that's a 1/8" p. thread going into the carburetor and sure as sh_ _ bottomed out !

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Re: how do you fix a gas leak?

Post by Mark Gregush » Mon Sep 07, 2020 11:12 am

Ether the threads are really deep or something else is going on. I am surprised the casting was not cracked turning it in that far! (or maybe it is?) While original type fittings were more forgiving, modern stuff is not because it is too hard. Anyway here is a photo of how I do it;
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I know the voices aren't real but damn they have some good ideas! :shock:

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Re: how do you fix a gas leak?

Post by TBones12 » Mon Sep 07, 2020 11:59 am

Got it. Thanks!

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Re: how do you fix a gas leak?

Post by ABoer » Mon Sep 07, 2020 12:03 pm

Bob , I use this one for years now , no problem .
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IMGP1099.JPG

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Re: how do you fix a gas leak?

Post by Steve Jelf » Mon Sep 07, 2020 12:10 pm

I got rid of mine. This explains why and how: http://dauntlessgeezer.com/DG106.html
The inevitable often happens.
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Re: how do you fix a gas leak?

Post by RajoRacer » Mon Sep 07, 2020 12:57 pm

There are numerous valves available to plumb inline - the "better" one that Lang's sometimes carries is a much better design - spring loaded as was the original Ford oil & radiator petcocks.


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Re: how do you fix a gas leak?

Post by Rich Bingham » Mon Sep 07, 2020 1:40 pm

Once again, non-original "improvements" present their own set of problems. The best way to eliminate leaks in any system is to limit the number of connections to a minimum. The aviation valve seal compound is effective if parts are well-fitted. Mostly it lubricates.
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Re: how do you fix a gas leak?

Post by Colin Mavins » Mon Sep 07, 2020 2:12 pm

My T has been in my family since 1960 the gas is never shut off once a year when it is parked for the winter the remaining gas is drained through the original drain and then closed in the spring we fill the tank and its good till winter. I don't know what problem is happening that you need to shut the gas off all the time .

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Re: how do you fix a gas leak?

Post by Steve Jelf » Mon Sep 07, 2020 2:30 pm

I don't know what problem is happening that you need to shut the gas off all the time .
If the float valve sticks open, as sometines happens, gas can leak out on the floor. If the heavier-than-air fumes reach a source of ignition the resulting fire can cremate your car, and in some circumstances you along with it. I believe most folks find this terribly disappointing. Granted, it rarely happens, but the potential is there.
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Re: how do you fix a gas leak?

Post by Mark Gregush » Mon Sep 07, 2020 2:34 pm

Colin Mavins wrote:
Mon Sep 07, 2020 2:12 pm
My T has been in my family since 1960 the gas is never shut off once a year when it is parked for the winter the remaining gas is drained through the original drain and then closed in the spring we fill the tank and its good till winter. I don't know what problem is happening that you need to shut the gas off all the time .
For many it is a safety issue because of storage. Wonder how many here have reported coming into where they store their T and found the whole tank on the floor from leaking over night? A little bit of dirt or rust flake will keep the shutoff valve open. Model A guys can reach down and shut their valve off and run the bowl dry and many do, same thing with many T owners. Not everyone has a brand new clean tank. I shut mine off more often then not, just for peace of mind.
I know the voices aren't real but damn they have some good ideas! :shock:

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Re: how do you fix a gas leak?

Post by Fordwright » Mon Sep 07, 2020 3:02 pm

Fuel shutoff valves were standard on nearly all machines for many years, not only for safety but to preserve precious gasoline from going on the ground. It's still fairly standard today on most gravity-fed fuel systems. It stopped being an issue when fuel pumps were used to draw the fuel from a low-mounted tank. On the Model T it's fairly straightforward; fuel will leak through by gravity when the car sits idle. It can also happen with a modern float carburetor. As the fuel evaporates, the float drops and more fuel enters the bowl. If the seal isn't perfect, or if there's a bit of pressure in the tank, it can leak through.

I cant think how Ford could have designed it better, except that the tank might have been mounted behind the firewall with a sight-glass and a fuel shutoff valve in view and in reach of the operator. But Henry Ford was one to believe that once something was designed to perfection, it need never be changed. He was proved wrong on that score many times, but he could afford to be "right." At least in his own mind.

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Re: how do you fix a gas leak?

Post by Mark Gregush » Mon Sep 07, 2020 3:12 pm

RE; except that the tank might have been mounted behind the firewall with a sight-glass and a fuel shutoff valve in view
Well except for the sight glass he did in late 1925-27. In Oct 1927 the A got the sight-glass and shut off valve in plain sight and was used till early 1932 when the B/Model 18 V8 came out with gas tank in the rear. :)
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Re: how do you fix a gas leak?

Post by Colin Mavins » Mon Sep 07, 2020 5:39 pm

all right then I have learned something today we have never had this problem with any of are old stuff I guess we have been very lucky Cheers Colin


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Re: how do you fix a gas leak?

Post by John kuehn » Mon Sep 07, 2020 6:38 pm

Undoubtedly this was an issue in the T era as it is today.
So did someone come out with some type of accessory in the T era to help with the leaking gas issue? I looked in my T era Western Auto T parts accessory catalog but didn’t see any.
I can imagine folks would take their leaking T’s to Ford shops to get the carburetor repaired or the gas tank shutoff fixed but surely there were accessory cutoffs that were custom fitted to their cars.

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Re: how do you fix a gas leak?

Post by Fordwright » Tue Sep 08, 2020 2:02 am

If you want something that was never designed into the car, you could connect a solenoid valve into the gas line so that it would be open only when the ignition is turned on.


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Re: how do you fix a gas leak?

Post by bobt » Tue Sep 08, 2020 6:02 am

That shut off valve is a POS. A $30.00 POS.

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Re: how do you fix a gas leak?

Post by Mark Gregush » Tue Sep 08, 2020 12:55 pm

Fordwright wrote:
Tue Sep 08, 2020 2:02 am
If you want something that was never designed into the car, you could connect a solenoid valve into the gas line so that it would be open only when the ignition is turned on.
Had something like that when I used the VW carb on my overhead. It was a constant draw on the electrical system.
I know the voices aren't real but damn they have some good ideas! :shock:

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Re: how do you fix a gas leak?

Post by Fordwright » Tue Sep 08, 2020 2:54 pm

Mark Gregush wrote:
Tue Sep 08, 2020 12:55 pm
Fordwright wrote:
Tue Sep 08, 2020 2:02 am
If you want something that was never designed into the car, you could connect a solenoid valve into the gas line so that it would be open only when the ignition is turned on.
Had something like that when I used the VW carb on my overhead. It was a constant draw on the electrical system.
You can wire it in series with an incandescent bulb. There is an initial surge of current to energize the solenoid, then as the filament heats up, resistance causes the current to decrease, but it's enough to hold the solenoid open. The light also serves as an indicator that the solenoid is open.

I have done exactly this, but I think I got lucky with the right size of bulb the first time.


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Re: how do you fix a gas leak?

Post by Allan » Wed Sep 09, 2020 6:21 am

A fuel tap with a shoulder like that one is designed to seal against a washer between the tap and the carb body. It will have a parallel thread. The standard elbow on the carb is a tapered thread, and winds in until tight[often in the wrong alignment] The carb body is not machined flat for a washer to seat against. It is the wrong tap for this application.

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Re: how do you fix a gas leak?

Post by GrandpaFord » Wed Sep 09, 2020 9:03 am

Allen is right. The normal pipe thread is tapered but there is a type of thread, mostly used in European countries, that has a straight thread and uses a gasket.

For the tapered pipe thread I use Teflon tape, either multiple wraps or the thicker variety used for gas lines. For the valve, there is a special lubricant that does not wash out with gasoline. It is called EZ Turn and is available from Langs, item number 2902LUB. It will make the valve turn easier and lasts for quite a while, depending on usage.

For my car, which is parked in a garage, I turn the gas off while the engine is running and allow the engine to run out the gasoline in the carburetor. I have a valve, the one from Langs, at the carburetor so I don't have to crawl under the car. If I am going to store the car for several months I will climb under the car and turn the gas off at the tank.

I have tried the solenoid valve to turn off the gasoline but it seemed to interfere with the gas flow. I like the manual valve because there is no guessing.


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Re: how do you fix a gas leak?

Post by DHort » Wed Sep 09, 2020 11:13 am

The biggest reason I gave up on trying a newer version is the normal pipe threads and the NPT pipe threads. I have not found a way to tell the difference unless I have some special tool. i will stick with the Lang's version, although I would rather have the teflon valve with the longer throw.

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Re: how do you fix a gas leak?

Post by Mark Gregush » Wed Sep 09, 2020 12:32 pm

Pipe threads are pipe threads, whether called normal or NPT. Generally there are only two types of threads used in pipe fitting depending on fitment, straight or tapered. White teflon tape should NEVER be used in a fuel fitting, only the proper type made for gas/fuel applications or pipe dope.
I know the voices aren't real but damn they have some good ideas! :shock:

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Re: how do you fix a gas leak?

Post by GrandpaFord » Wed Sep 09, 2020 5:51 pm

Mark,

The tapered pipe fittings are NPT and the straight threaded fittings are designated NPSC or IPS. In the size we are talking about the threads per inch are the same and the OD is equal at the small end. As you can imagine, mixing the two threads will result in problems.

I am curious why your say that Teflon tape should not be used on gasoline fittings? I know silicone will dissolve in gasoline, but Teflon is not effected. I know that if the tape is not put on correctly, that pieces of the tape can flow down stream and cause problems. Is there another reason that I don't know about?

Neil


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Re: how do you fix a gas leak?

Post by DHort » Wed Sep 09, 2020 7:09 pm

FWIW, Jamestown Distributors(boating) states that backyard mechanics use yellow teflon tape. However, there is always a risk that a piece of tape can break off and clog your fuel line. It also states that the yellow tape is for propane, butane, and natural gas.

They recommend liquid or paste, Permatex Aviation Form a Gasket #3, or Permatex High Temperature Thread Sealant.

https://www.jamestowndistributors.com/u ... ?docId=563


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Re: how do you fix a gas leak?

Post by bobt » Thu Sep 10, 2020 6:21 am

If I'm not mistaken, I think he's saying the valve itself is leaking and not the threads. I bought TWO of those valves and had problems with both of them. They both worked fine at first and then became so hard to turn that I had to use pliers to shut them and then they started leaking. Some folks on the forum say to pull up on the handle while you turn the valve on / off. I bought a four dollar atv valve from ebay and it works great. That's why I said that valve is a POS.

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Re: how do you fix a gas leak?

Post by GrandpaFord » Thu Sep 10, 2020 7:40 am

Screen Shot 2020-09-10 at 7.38.15 AM.png

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Re: how do you fix a gas leak?

Post by Fordwright » Fri Sep 11, 2020 3:35 pm

This is what my dad was raised on, back in the day...
SealAll.jpg
SealAll.jpg (39.74 KiB) Viewed 489 times
when water in the gas tank meant a lot of holes rusted through.

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