Pinhole leak in my gas tank - how to fix?

[rob650]

its about 1 inch behind the gas tap, on the angled surface.  

I've heard of the kits that strip and reseal the inside of the tank, would this fix the problem?  I've never dealt with a leaky gas tank before.

Thanks.  Dang if its not one thing, its another....

[Ed Miller]

If it's just one tiny pinhole then Caswell would probably fix it.  I would not be surprised if there's general rust in that area and that may just be the first.  Unfortunately I can't think of a way to see the inside of that side of the tank.  

[Justin B.]

POR-15 also claims to fix pinholes and includes a piece of something (cloth?) to fix larger holes with as well.  They say to cut a suitably sized chunk of the cloth, saturate it with POR-15, and then put over the hole.  Sounds like the same procedure as patching holes with fiberglass.

[Bob_Roller]

If it's just one tiny pinhole then Caswell would probably fix it.  I would not be surprised if there's general rust in that area and that may just be the first.  Unfortunately I can't think of a way to see the inside of that side of the tank.  

If you have a small telescoping mirror, you may be able to get it in the tank, and shine a flashlight from the filler opening, and have a look inside .

[montmil]

If it's just one tiny pinhole then Caswell would probably fix it.  I would not be surprised if there's general rust in that area and that may just be the first.  Unfortunately I can't think of a way to see the inside of that side of the tank.  

...shine a flashlight from the filler opening, and have a look inside .

...or a match [smiley=evil.gif] THAT oughta fix it!

Probably right about additional rust lurking on the inside. I'd suggest a temporary patch job, even if it is butt ugly, and start searching for a replacement fuel cell.

Monte

[williamemack]

If you end up needing a new tank, try Duncan's Beemers, www.duncansbeemers.com, tel 978-897-2697. He seems to do a lot of business in R65s and generally has a shed full of airhead parts.

Will Mack

[Ed Miller]

If you could train your pet octopus, you could put the patch INSIDE the tank where it won't show.  Unfortunately that's the only method that comes to my mind.

[Bengt_Phorqs]

I've had good luck with POR15 on a Karmann Ghia.  Had to replace the gas tank and also used it to seal the inside of the tank.  Also used it to seal up some rusty spots under the frame and it's great stuff.  Be sure to wear gloves though.  If you get it on your hands it will take a mighty long time to wear off.

The bigger issue though is the rust inside the tank.  I just went through that myself.  When I removed the truck bed liner from the outside of the tank (the PO liked the really "gnarly" look) I found where he had applied a generous amount of JB weld to the holes.  If it's bad enough to rust through with pin holes then in all probability you have some serious corrosion issues.  If you're determined to keep that tank then you definitely need to take it to a radiator shop first to be vatted and then try the POR15 fix.

[rob650]

Ed : little Ocho hates confined dark spaces, otherwise I'd follow your advice.

Williemack : thanks for the heads up on that salvage yard.  They do have a tank for $260.

I'll try the Caswell or POR15 product, and see where that gets me.  

Thanks everybody for the advice.  Mom says, "Well, can't you just call BMW and buy a NEW one?".....  

[Darwin_R65]

The guys in the car club that play with vintage cars and bikes use the POR stuff.

But they have built a rotisserie for this purpose.

they soak the tanks in Diesel I think to remove all the crap inside and then pour in the tank sealer and turn the rotisserie on overnight.

[Ed Miller]

snip  Mom says, "Well, can't you just call BMW and buy a NEW one?".....  

You probably CAN but is she offering to pay for it?

[Justin B.]

I found (during my last tank sealing episode with Eastwood's sealer) that Muriatic Acid will completely dissolve rust if left in long enough.  The inside of the tank used on the Junkyard LS project was completely grey after about a 9-10 hour soak...  The POR-15 product does not require this as I think it also "converts" rust so it doesn't have to be completely removed...

[Darwin_R65]

The POR 15 instructions suggest using their metal-ready rust remover before painting por-15. Or if you sandblast there is no need for preparation, but of course sandblasting inside a tank is not a practical solution.

[Ed Miller]

The advantage of POR 15 is they send you a kit with all three compounds you need, the cleaner, the metal ready stuff, and the actually POR 15 coating.  If you still have some old lining in the tank I think they sell separately something that will remove that.  

[rob650]

Ed; when you say "old lining", do you mean the original lining when the bike was new, or something done by a previous owner?

Inside of my tank looks red(ish) in color.