# leaking gas tank



## leftyfretguy (Jan 2, 2008)

Hi all,

My Accucraft forney has developed a leak in the gas tank. I can't even get one loop of my layout before it is out of gas. This includes topping up after the safety lifts.


Any tips on how to repair this?


thanks,


Matt


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## hawkeye2 (Jan 6, 2008)

Have you determined that it is actually the tank? After locating the leak (pinhole, crack, or whatever) clean all paint off the offending area, purge the tank and do a silver solder repair or replace it if you don't feel confident in doing that.


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## weaverc (Jan 2, 2008)

Is the filler valve leaking? It has an O-ring that may be damaged or the device is just loose.


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## HMeinhold (Jan 2, 2008)

Matt,
don't run your loco until you have located/fixed the leak. You might create a big fire ball. Guess how I know








Regards


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## steveciambrone (Jan 2, 2008)

To find a leak remove the tank from the Loco and put a little gas in it and dip it in water. The leak will be were the bubbles are comming from. 

Steve


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## hcampbell (Jan 2, 2008)

Wouldn't it be easier to leave the tank in place and brush some soapy water around it to spot the leaks? 

Harvey C. 
SA 1838


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## gwscheil (Aug 6, 2008)

A small squirt bottle filled with dilute dish washing soap should be perfect. Just remember to rinse the soap off after you are finished. Probably a loose filler, damaged o-ring seal, or a loose packing nut on the fuel valve.


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## hcampbell (Jan 2, 2008)

If it's not a leak. I've been having problems with short runs due to the filler valve icing up when using Korean butane. 

Harvey C. 
SA1838


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## steamboatmodel (Jan 2, 2008)

If it is the tank itself that is leaking I would return it to Accucraft rather than try repairing it. Remember that the Gas Tank is a pressure vessel the same as a Boiler. After any soldering repairs it should be hydro tested to 350psi. 
Regards, 
Gerald


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## Charles (Jan 2, 2008)

Gerald
Where did you get the hard number of 350 psi?


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## Eric M. (Jan 3, 2008)

I would eliminate all the other possible leak points first, like the fuel line to burner connection may be loose or leaky, the filler valve, as some have suggested, or the o-ring on the control valve (these Accucraft valves don't have a packing nut-- only an o-ring.) 

I had an Aster WM Shay once that developed a leaky fuel tank. It turned out the filler valve was a bit loose I could actually hear the gas escaping. I tightened it down and the leak stopped. I hope your situation is just as simple. If the tank itself leaks, I would ask for a new one from Cliff at Accucraft. 

Regards,


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## Shay Gear Head (Jan 3, 2008)

Sounds like it is time to make a filler valve tightening tool!

Take a screwdriver that fits the width of the filler valve and its slot and then using a Dremel tool cutting wheel grind out the center so it fits over the nipple of the filler valve.

You'll need this tool more than once in your lifetime I'm sure.


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## Nutz-n-Bolts (Aug 12, 2010)

I had a similar problem. It was either icing as Harvey described, _or_ what I think was a bad tip on the can. I got rid of the can and the problem disappeared. I knew it wasn't filling long enough before it started spitting out. 

Also,One way to test for a leak in the tank would be to fuel it and check it several days later to see it it has retained it's charge. This might rule out a leak and point to not getting enough fuel in.


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## leftyfretguy (Jan 2, 2008)

Update, 
I could feel the gas escaping and kind of assumed the filler... Did the water spray check tonight and it bubbled like crazy at the o ring. I will try to tighten it after I get a tool made up but the o ring looks pretty shot. Can I pick up a replacement at the hardware store? Any one know the size? Is there a special type I have to use? 
thanks for the help! 
Matt


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## gwscheil (Aug 6, 2008)

The o-ring should be a standard Metric size, or just ask Cliff to mail a few.


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## steamupdad (Aug 19, 2008)

What color is the o-ring? Black, orange, green, clear? This matters. If it was a black o-ring (funny feeling it is), you will keep having problems. Black o-rings cannot handle the cold. They get hard, stiff, brittle, crack. I recommend going to the auto parts store and getting a green o-ring. They are used in refrigerant systems. And they do come in tiny sizes. Give it a shot.


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## steamboatmodel (Jan 2, 2008)

Posted By Charles on 28 Sep 2011 12:27 PM 
Gerald
Where did you get the hard number of 350 psi? 
I asked one of the former manufacturers and he said that that was what the EU regulations required. 
I checked what the vapour pressure was for various mixture and 350 sounded reasonable.
http://www.engineeringtoolbox.com/p..._1043.html
Regards,
Gerald.


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