hole in my gas tank

[monty101]

I had a bubble appear on my gas tank. I stuck a pin in it and gas came out. The leak had caused the bondo to separate from the tank. I cut the bondo back over the hole and filed it with water and let it set over nite and its still dry. whey isn't it leaking?? I'm thinking I need to take it to a radiaor shop and let them pressuize it and I'm betting they can braze up the spot where ever the hole is. Is there some kind of sealer that I could use. I think I can see the small crack where
it was originally brazed up. It looks like the guy didn't get the crack he brazed up completely covered. I thinking I could put some JB weld on it and fix it. Anybody have any ideas?? I already got it flushed out and I stuck a match in it this morning to make sure it won't explode. Just looking for a simple fix.

[76shuvlinoff]

There is a gas tank patch kit from NAPA (get the one for steel tanks) that worked for me but I used it inside next to the frame and could leave it on thick.  I also went overboard since it was next to a rear mount. I laid on a layer of JB weld first, let it cure out then the patch kit over the top of that.  Been 3 years now and still holding. 

[monty101]

I pressure tested it myself and I can see that there is air coming out the place where the welder didn't get the crack completely brazed up. Its about 1/16 inch long.  I'm thinking I might just take it back to him and have him finish the job. May mess up the paint and bondo but what the heck I got to repaint it anyway. It took pressure to get it to leak. It didn't leak a drop when I filled it with water and let it set overnite.

[76shuvlinoff]

I don't know this for sure but if gasoline molecules are smaller than water molecules it would take pressure to make it leak. I pressure tested mine at 3 to 5 psi after I patched it.

Brazing is probably the best way to go.  Good luck.

[easyricer]

I gotta repair a leak on both of my tank halves. I'm gonna do that tonight. I'll just tig them up with stainless filler rod. I'm not gonna sweat any liner or sealer.
EASY

[MMOCGuy]

JB weld will work but it needs to be on thick enough and spread wide enough so that the vibration of the tank doesn't crack it. Brazing it will be the best bet. If you can't do it yourself, then have your guy rebraze it. Actually, welding it would be the the most permanent however, once it has been brazed, it will be very difficult to get all of the brass off so that a weld will stick. I have brazed tanks to repair cracks like yours and they have lasted years so, again, that is the way I'd go. One thing I do is when I mount my tanks, I insulate them from the frame with rubber plumbing washers. You will find a great assortment at your local hardware or home improvement stores. You should be able to find washers that will work perfectly for both the front and rear mounts.

Hope this helps.

Norm.

[NormL]

Old welded up cracks?  Leaks in the gas tank?  Friggin around with bondo, JB weld or leak sealers is MM.
Why not buy a new set of tanks?  Glutton for punishment?  <g>

NormL

[flhswingarm]

Wut Norm sez............ I welded,patched, plugged,replaced,shimmed new tanks, retightened, rewelded,.................then put new rubber mount tanks & mount kit.......... once metal fatigue starts old tins aint worth a dime

$0.02

[monty101]

I'd post the pic but its 429k and I can't get it to save any smaller. I put rear cross overs tubing on 5 gallons tanks so I can get all the 5 gallons and I welded on some extensions that I modified to look like I wanted. I punched a hole in the tanks so I had them brazed up hence the problem I'm having now.  I think I'll take them back to the dude tomorrow that missed 1/16 inch of the hole(crack) when he brazed them and get him to fix them right and use them. they aren't rusted and why spend 100-200 bucks for some more that won't have a rear spigot or rear crossover tubing and won't have the customized extensions I put on. They look great just wish I knew how to get them to post. Oh, well....

[monty101]

figured it out. here's the pic

[attachment removed after 60 days by system]

[greenshovel0014]

braze it yourself. if you don't know how get a piece of steel and practice.

[pappyfreebird]

sweet tank,,,i should dig out me leather stuff n make sum tank chaps,,still have a couple,,,but think ony stock flh n lowrider dash style..all the stretch n dif dashes made it hard ta git right size ,,so ain made any fer awhilst

[NormL]

Wow, those are nice tanks.  I'm sure it will braze up and be fine.   

[monty101]

Learned my lesson. If a scooter shop has a sign in the window that says "welding, aluminum, plastic etc." don't take your stuff in there. took the tank back and the guy rebrazed it and of course didn't put water in it or pressurize and I took it home. He didn't charge me but it probably took about 15 seconds to put the add'l brass on the tank. I pressurized and sure enough now it had 3 leaks. I then took it to a radiator shop and he silver soldered it and now it doesn't leak. He pressurized it right while I watched and I helped him and it doesn't leak now.

[MBSKEAM]

I bet the cracks will run....
put the tanks on and run them as is before paint

to stop a crack you can find the end and drill a small hole, otherwise if you braze or solder the crack is still there, the steel needs to be fused back togethor, not covered up

just my 2cents

mbskeam

[easyricer]

Well as I said on the other post I shoulda looked a bit closer. Looks like i had 2 holes and not just one in mine.
I tigged up the one hole figuring that was all of it. never checked them that night. Next morning added about a gallon of gas to find a leak right around the same area. So I guess I got two.
I'll tig it up this weekend I hope. Til  then I'm riding on the left tank alone. That one tigged up good and has no leaks.
BTW Tig welding a tank with stainless rod is the only PERMANENT repair that there is. Brass and silver will eventually leak again and will not stop a crack.
EASY

[monty101]

you know I guess I may not have got it fixed permanenetly but I 've already bondoed it and got it ready to paint. The holes did not start off as cracks. I punched a hole in the tanks using a stick welder to tac weld the extensions on. I got a set of cherry 4.2 gallon tanks, I may cut then and actually weld some extensions on them he right way, move the spigot back and put a rear crossover on them. I'll start looking for some more extensions. I'll rubber ,mount them and cross my fingers. When I decided to take it to the radiator shop. I found the leaks were not only coming from the brazed spot but from where it had been tigged too.

[MMOCGuy]

Monty.

If it was leaking from that many places and has been repaired several times, I'd start worrying that metal fatique has taken its toll and It might only be a matter of time before it starts leaking again. I'd keep a real close eye on it.

With that said, I never thought about the idea of a radiator shop. That's a great idea and one to remember should the need ever arise.

Thanks,

Norm.

[monty101]

It was just leaking out of a couple places where I burned a hole in it tack welding the extensions on. I don't think there's a lot of metal fatigue. If I hadn't burned those holes it would not have leaked. I'll watch it but I think it will be ok. I've read where guys have plugged leaks with jb weld so I think the solder will be ok but who knows. Oh well you live and learn. I'll never use a stick welder on a gas tank again. I'm sure tig welders do a heck of a better job.

[Hogmosh]

JB Weld worked for me as well.The mount bracket on an old Triumph broke and started to leak.Great stuff.Hogmosh

[verson22]

Monty, I'm not a fan of tank liner/sealer , but this might be a good case to try it.