Found the gas leak ; how to fix it ?

[unclepete]

Got the bike in April . 1994 California 1100 . 32k miles . Tires were 18 years old with lots of tread left . Lots of time on side stand .
The left floorboard rubber was eaten up from gas having dripped on it .
I replaced petcocks and hoses , and the seal on the fuel level sensor , and thought I had fixed it .
After a couple of weeks on the center-stand , I felt around , and the petcock and fuel sensor areas were dry , but it was slightly damp on the seam of the tank ahead of the bungs .
The leak is behind the C shaped mount ; I'm guessing the metal was thinned at the weld .



I do not want to destroy the finish because the second owner had some pinstriping done to honor his friend , who only enjoyed the bike for the first year . Side-covers and fairing to match .



The inside of the tank looks spotless from what I can see , so I hesitate to use some kind of coating on the inside .
How about using silver solder on the outside ?

 


 

 

[jcctx]

Had a similar leak on a Yamaha; a patch of JB weld worked a treat!!

[Chuck in Indiana]

How about using silver solder on the outside ?

That will work fine. There are also special fuel proof 2 part epoxies that will "probably" work in that location.

[PeteS]

I used this about 20 years ago on my LeMans tank. Still working, no leaks. Its paintable too.



Pete

[RinkRat II]

   Looks like this is the way to go^^^^^^^^^^^^^^^^^^^and if it doesn't work you could always silver solder as you suggest. Just be sure to purge the tank with Nitrogen whilst soldering. In the immortal words of Pat Travers  "Boom Boom and Out Go The Lights" 

         Paul B

[pehayes]

Common hardware store product works very well.  SEAL-ALL.  Thin consistency like model airplane cement.  Clear, transparent.  Use two coats.  I've done it on numerous fuel and oil tanks.



Patrick Hayes
Fremont CA

[bigbikerrick]

Myself, being a "belt ,and suspenders" type of guy, I would use a couple of coats of the seal all Pat recommends, then a coating of the gas tank repair epoxy made by permatex on top of that, for extra protection.
Rick.

[bmc5733946]

 An old school radiator repair shop can solder this with acid core solder very effectivly with low heat and consequently little damage. They will probably fill it with running water while doing the repair. The mounting points that hold the rubbers are somewhat adjustable, with some forcing they can be made to align so that they don't apply pressure to that area of the tank.

Brian

[Wayne Orwig]

Been there, done that.


I had a 1994 California 1100 that leaked in the same spot, on the left side. Ate up the floorboard rubber too.

I believe there is a lot of flexing and stress from the tank mount right there.

I tried to solder it. Did not hold.
I tried solder and JB Weld. Did not hold.
I tried silver bearing solder and JB Weld. Did not hold.
I tried silver bearing solder, a metal plate, and tank sealant (POR-15). That held.

I got a good deal on a replacement tank and installed that, so I don't know if the soldered plate with sealant was a good solution. I do know that simply putting solder on it is worthless.

[Gliderjohn]

You did replace the tires, right?
GliderJohn

[unclepete]

Been there, done that.


I had a 1994 California 1100 that leaked in the same spot, on the left side. Ate up the floorboard rubber too.

I believe there is a lot of flexing and stress from the tank mount right there.

I tried to solder it. Did not hold.
I tried solder and JB Weld. Did not hold.
I tried silver bearing solder and JB Weld. Did not hold.
I tried silver bearing solder, a metal plate, and tank sealant (POR-15). That held.

I got a good deal on a replacement tank and installed that, so I don't know if the soldered plate with sealant was a good solution. I do know that simply putting solder on it is worthless.

That's really disappointing .
I have been looking at pictures of tanks , and notice that the newer ones have a sheet-metal disc that the mount is attached to .
Seems there is no shortcut . I suppose the metal is too thin to braze all the way around the mount .
So , to fix it properly I would need to grind off the mount after making a template to re-position it , weld it to a disc , then solder the disc into position .


gliderjohn : I have new tires on the bike , but did ride it a couple of times before the new ones arrived .
Safety concerns aside , the  difference in handling was obvious even to me , a not very aggressive rider .   

[Wayne Orwig]

Too much flexing I guess.  True silver solder might be good. The low temperature silver bearing solder was not good enough.

Sent from my SM-N950U using Tapatalk

[Rebochi]

   I have used tank cream successfully on small leaks. I put a couple of hand fulls of gravel in the tank and shook it until I got weary f shaking it. Removed the gravel with a shop vac with a small hose taped to the regular hose The kit comes with a acid based cleaner and a MEK rinse.


https://www.amazon.com/Kreem-Products-Fuel-Liner-Combo-Pak/dp/B001J0DHZK

[Chuck in Indiana]

True silver solder might be good.

It is..

[Chuck in Indiana]

I think we have a difference in semantics here.. what machinists call "silver soldering" is actually silver brazing. Brazing uses a different flux and temps are *much* higher than soldering. The rod for brazing has a lot more $ilver, btw. Jewelers use silver solder.. that won't fix your tank.

[unclepete]

The silver solder I was thinking of is 96/4 . 96% Tin and 4% Silver ; melts about 450 F .
I looked in the drawer and the flux had leaked inside the container and my silver solder has crystals on it , and the data sheet is mostly eaten up by acid . I used it last to join a handwheel to a piece of 1-1/2" d.o.m. for a collet closer on a lathe . It held , so there is a good chance that it would hold a 3" sheet-metal disc to a flat surface on the fuel tank , if properly prepared .
The leak is tiny , so I was tempted to clean well on the outside and apply the solder , but the concern is cleaning well enough between the mount and the tank .
My friend Mike is a good TIG welder . I'll run it by him .   

     

[Kiwi_Roy]

I do not want to destroy the finish because the second owner had some pinstriping done to honor his friend , who only enjoyed the bike for the first year . Side-covers and fairing to match .



The inside of the tank looks spotless from what I can see , so I hesitate to use some kind of coating on the inside .
How about using silver solder on the outside ?

I thought the whole point was to save the pin striping in honour of a friend
I would line the tank with Caswel or get another tank and put it on the shelf.

[unclepete]

I thought the whole point was to save the pin striping in honour of a friend
I would line the tank with Caswel or get another tank and put it on the shelf.

He wasn't my friend . I did not know him . I am the fourth owner . Second owner had the pinstriping done after buying the bike from his friend's widow . Not long after that he started to lose his vision , became unable to ride , and sold it to the guy I bought it from .
The leak is tiny , and the inside of the tank looks to be in great shape (washed it out today ) .
I hesitate to coat the entire inside of a tank to take care of a pinhole .
It is a metal tank and I prefer to use metal for a lasting repair .
I rinsed out a lot of the failed red liner from my BMW R80 tank not too long ago .
The problem I have with using any of the plastic/epoxy repairs is that gas formulations have been changing and what may be fuel/gasoline resistant today , may not be resistant in the near future . Fiberglass tanks are an example .
It's a nice tank with a small leak , and it's not going up on a shelf ; that would be like giving up .
I thank you all for the suggestions .
 

[PeteS]

Again, the Permatex epoxy stick has lasted me 20 years. You don't need much. Just make sure to degrease the area before applying. Then touch it up with a artist brush.
As for tank lining the Caswell plating product will last though I would save it for the second step if needed.

Pete

[Chuck in Indiana]

Again, the Permatex epoxy stick has lasted me 20 years. You don't need much. Just make sure to degrease the area before applying. Then touch it up with a artist brush.
As for tank lining the Caswell plating product will last though I would save it for the second step if needed.

Pete

Agreed. I used the epoxy stick to repair the Jack All hack tractor tank, and it was a good repair for as long as I had it. Of course, the key to any adhesive product is prep.
FWIW, I have seen some failed Kreem jobs, and agree again that Caswell is the best I've used.

[Rough Edge racing]

The silver solder I was thinking of is 96/4 . 96% Tin and 4% Silver ; melts about 450 F .
I looked in the drawer and the flux had leaked inside the container and my silver solder has crystals on it , and the data sheet is mostly eaten up by acid . I used it last to join a handwheel to a piece of 1-1/2" d.o.m. for a collet closer on a lathe . It held , so there is a good chance that it would hold a 3" sheet-metal disc to a flat surface on the fuel tank , if properly prepared .
The leak is tiny , so I was tempted to clean well on the outside and apply the solder , but the concern is cleaning well enough between the mount and the tank .
My friend Mike is a good TIG welder . I'll run it by him .   

   

 I use Silverbrite  8 ,a 4 % silver bearing soldier for the ends on control cables...If nothing else, all soldering needs a very clean prepped surface...
  I have done welding on quite a few fuel tanks...Several flushes with lacquer thinner and then isopropyl alcohol with the shop vac on blow for drying in between...Others have different approaches to this...I mention this because a good TIG welder might be required...
  I believe any type of epoxy or urethane liner is a last resort when welding/brazing/soldering has failed...
 What Pete S shows, I used that same product on a Triumph fuel tank 35 years ago and it was fine for years...I hear people say that regular epoxies will fail with modern fuels...

[PeteS]

Silver solder would be the way to go if you intended to repaint the tank. Otherwise the heat will just damage more of the paint. I didn't want to repaint my LeMans tank so I went with the Permatex. Besides the patch is covered by the seat. If it ever does fail you can just file it off and try something else.

Pete

[Wayne Orwig]

Silver solder would be the way to go if you intended to repaint the tank. Otherwise the heat will just damage more of the paint. I didn't want to repaint my LeMans tank so I went with the Permatex. Besides the patch is covered by the seat. If it ever does fail you can just file it off and try something else.

If it is like mine, the leak is on the inside wall. Not near the outside. With care the outer paint should be safe.

[Chuck in Indiana]

If it is like mine, the leak is on the inside wall. Not near the outside. With care the outer paint should be safe.

My Jack All was the same. The process of stretching the metal when forming makes it thin there.

[Mike Tashjian]

I used Dry Ice pellets to make the tank inert after a thorough cleaning and mig welded my Stone tank.  I look up at it with a small mirror from time to time and it looks great.  The added metal is making the area a bit thicker and so far so good.  Mike

[unclepete]

My friend Mike TIG welded it for me today . I had rinsed the tank with soapy water a couple of times yesterday , and today we ran mixed shielding gas into the tank to displace oxygen .
A thorough cleaning and a little heat revealed a crack just below the beginning of the original weld , about 1/4" from the end of the mount . Mike welded that up , then I cut the end off the mount and ground down to the tank to reveal the other end of the crack . He welded that , and the tank no longer leaks .
How did a crack develop 1/4" from one end of the mount , perpendicular to the original weld ?
I will work on improving the fit ; it seems tight going on and off , which seems desirable , but the mounts rub on the brackets that hold the rubber round pieces . Not an ideal setup ; gas leak with metal on metal contact . At least the leak part is fixed .