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Fueltank leak

Discussion in 'Technical Q&A' started by Corsa308, Mar 8, 2008.

  1. Corsa308

    Corsa308 Formula Junior

    Apr 22, 2007
    281
    Sydney, Australia
    Full Name:
    Steve D
    #1 Corsa308, Mar 8, 2008
    Last edited by a moderator: Sep 7, 2017
    Have a look at this.
    My tank was leaking somewhere. I would get a small wet patch on the garage floor.
    The leak was only just enough to produce a drip.
    On inspection I couldn't find the source so I decided to remove the tank.
    So this is it. The tank is protected by a set of felt pads on most sides.
    This section in the photo is where the bottom felt pad normally sits.
    Strange that it doesn't have any of the thick silver paint on it so they must spray it on the tank and the engine bay once installed.
    Once I removed the tank I supported it and added a small amount of fuel back into it and waited for action.
    Thirty secs later one of these holes started to weep. So there you have it.
    I have a leak and a corrosion problem.
    But now what to do?
    Cut the section out and replace?
    Weld a new alloy patch over it?
    Fibreglass over it?
    Whats are your thoughts?
    The first two would have to be outsourced but I could do the fibreglassing.
    These cars are getting old, but I reckon that my car may not be alone in this problem.
    Keep your eye open for anything similar on your car.

    Steve
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  3. Steve King

    Steve King F1 Rookie

    Feb 15, 2001
    4,366
    NY
    I would 1st get a bore scope and look at the inside of the tank to seee what kind of problem you have. If this area is the only problem then I would cut and patch the area and fill it. It looks like a fairly flat area so it should not be to difficult to braze in a patch. Good luck
     
  4. wrxmike

    wrxmike F1 Veteran
    Silver Subscribed Owner

    Mar 20, 2004
    5,762
    AU
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    Michael
    There should have been a rubber sheet between the tank and the base it sits on. The tanks are painted outside the car ( all around ) the pits in the photo look like electrolytic corrosion that you get between 2 dissimilar metals touching ( hence the rubber sheet )
    Eastwood supply a kit to seal the inside if the tank, it may also be possible to get a replacement section welded in to the fuel tank (potentially dangerous, needs a professional to do it )

    Michael
     
  5. Corsa308

    Corsa308 Formula Junior

    Apr 22, 2007
    281
    Sydney, Australia
    Full Name:
    Steve D
    Yep, the pad was there but they are a felt type of substance.
    Old but still servicable.
    I will replace them when I re-install.

    Steve
     
  6. PAP 348

    PAP 348 Moderator
    Moderator Owner

    Dec 10, 2005
    86,676
    Mount Isa, Australia
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    Pap
    Take the tank to a fabrication workshop mate. One that specializes in fuel tank repairs. :):)
    They will braze fill it and pressure test the tank to look for anymore leaks. :):)

    I cannot recommend anyone in Sydney, as I do not know that place at all. :):)
    Unless you want to send the tank here. :p:p

    Do not attempt to braze weld it yourself mate. Let the pro's do it brother. :):)
     
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  8. Corsa308

    Corsa308 Formula Junior

    Apr 22, 2007
    281
    Sydney, Australia
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    Steve D
    Pap, and you don't think that fibreglassing it is the go?
    All the resign will seal off the weep holes and a nice fibre patch over the whole thing?

    Steve.
     
  9. eulk328

    eulk328 F1 Rookie

    Feb 18, 2005
    2,726
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    F683
    I had a pinhole leak on one of my tanks (on the bottom!) and fixed it with J-B Weld for about $5.00 So far no problems but I only did it last summer so I don't have any long-term data.
     
  10. PAP 348

    PAP 348 Moderator
    Moderator Owner

    Dec 10, 2005
    86,676
    Mount Isa, Australia
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    Pap

    You probably could do that mate? :):)

    I have never seen it done and have not heard much about it at all. We normally get them brazed up, always did the trick. :):)

    But, give it a go if you like? It could be a good thing Steve. :):)



    That stuff is really good. Have used it before on engine sumps to plug leaks. Never kept it that way for long. We would normally get the cars back to replace the sump. :):)

    I guess fuel tanks would work the same. Whatever works I guess. :p:p
     
  11. eulk328

    eulk328 F1 Rookie

    Feb 18, 2005
    2,726
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    F683
    If I recall correctly, there were a few different versions (mixtures) of J-B Weld. Of course I got the one that is meant to be gasoline resistant.
     
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  13. wrxmike

    wrxmike F1 Veteran
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    Mar 20, 2004
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    Michael
    I second Pap's comments, JB Weld & Fibreglass are not really permanent repairs - strip the coating off the tank , asses the condition and then get it repaired in metal - either with a braze or a new piece TIG welded in. Re-finish the tabk exterior with a WURTH product - anti chip coating , then spray the whole lot silver, will look like new. Been there, done that.
    Also, good idea to check the conditon of all the fuel lines, as well as the rubber section on the balance pipe between the two tanks. 308's are notorious for engine bay fires, the OEM cloth covered fuel lines can detoriate while still looking OK on the outside, eventually breaking and spewing fuel across the motor. The car will then burn to the ground in about .5 seconds flat. ( especially 'glass GTB)

    BTW, nice car, I've got similar,not many RHD/ Dry Sump / Glass cars around, what's the chassis number on yours?

    Regards
    Michael
     
  14. eulk328

    eulk328 F1 Rookie

    Feb 18, 2005
    2,726
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    F683
    Engine sumps see much higher temperatures, go through heat/cooling cycles and probably expand/contract at a different rate than J-B weld (if it expands/contracts at all).

    No leaks on my fuel tank for six months so I it works for me and was worth 5 bucks. Maybe tomorrow it will no longer hold and I'll have to get it fixed "properly." No worries..... keeping in mind this was a pinhole leak that was just barely "weeping" gas and not a big leak or a large hole I patched.
     
  15. PAP 348

    PAP 348 Moderator
    Moderator Owner

    Dec 10, 2005
    86,676
    Mount Isa, Australia
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    Pap

    Hey, no worries there mate. :)
     
  16. Martin308GTB

    Martin308GTB F1 Rookie

    Jan 22, 2003
    4,125
    Black Forest Germany
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    Martin N.
    Hello from Germany,

    it would be interesting to know, WHAT has caused this corrosion pin holing. Did it come from the outside or the inside ? Though I don't believe it has something to do with, it reminds me of the current concerns over here in Germany regarding bio-fuels.

    I will start a separate thread about this.

    Best Regards

    Martin
     
  17. wrxmike

    wrxmike F1 Veteran
    Silver Subscribed Owner

    Mar 20, 2004
    5,762
    AU
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    Michael
    Martin, I think this is the likely cause, the corrosion is only where the tank was sitting on the felt pad, the car was from the UK, and I bet the felt pad was damp, ( ie conductor ) . Hence better using a thin sheet of rubber, which does not allow a current to pass when wet.


    http://en.wikipedia.org/wiki/Galvanic_corrosion#See_also
     
  18. eulk328

    eulk328 F1 Rookie

    Feb 18, 2005
    2,726
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    F683
    Michael,

    On my fuel tank the pinhole leak is on the bottom, not far from the fuel pipe outlet (LH tank). No contact with felt pads or anything else.
     
  19. andrewecd

    andrewecd Formula Junior
    Silver Subscribed

    Dec 17, 2006
    534
    Sydney
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    Andrew
    Steve, yes, I did this exact method on an old tractor steel tank (Fergie).
    Tank sat right on top of the motor and leaked fuel all over it!!!.
    Just cleaned as much rust and loose metal as possible to create a good bond and fibreglassed the whole bottom of the tank.
    Got a bit carried away and glassed almost to the top.
    Worked a treat and had no more prob's. As tank is quite exposed, I was able to keep an eye on the repair and it held up brilliantly.
    Even fuel filter stayed clean.
    Had that beast for another 5 years until everything else on it began to quit, so bought a new Kubota. Tank was still in perfect shape!
    Big diff between F car and an old TE fergie...but it did work well.
    Good luck.
    PS. Before I glassed it up, I smothered tank in rust convertor.
     
  20. Corsa308

    Corsa308 Formula Junior

    Apr 22, 2007
    281
    Sydney, Australia
    Full Name:
    Steve D
    Thanks for the suggestions guys.
    Today I took the tank to a welding guru I know and I am having it welded rather than glassing.
    I think the pix show it quite clearly but I reckon it may be some form of Electrolytic attack.
    It seems to only be where the pad touched the tank.
    I am going to replace all the pads with rubber.
    While I am at it I will replace the tank interconnecting hoses as well. Just ordered them from Superformance.
    This fuel tank fix is the last thing I needed as I am going to run the car @ Bathurst in the Historics @ Easter.
    Needless to say that I really don't need any fuel leak problems on the track.
    I will post some pix when I get back and hopefully some video as well.
    About time an F-car got to run Bathurst @ speed.

    Steve.
     
  21. wrxmike

    wrxmike F1 Veteran
    Silver Subscribed Owner

    Mar 20, 2004
    5,762
    AU
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    Michael
    That's unusual, perhaps there was something inside the tank that caused the electrolysis (something in the tank like a bolt or a nut from the assembly process? ) .
    With regard to the ethanol based fuels now becoming more common, I don't think they attack aluminum, but they can certainly damage rubber
    components in the fuel system.

    Michael
     
  22. eulk328

    eulk328 F1 Rookie

    Feb 18, 2005
    2,726
    Full Name:
    F683
    There wasn't anything in the tank. I pulled the tank out and had the float mechanism out also and there was nothing loose inside.
     
  23. 308tr6

    308tr6 Formula Junior

    Dec 23, 2003
    466
    SDakota
    Full Name:
    Rico
    Having restored a few cars in my life, it is interesting that the most common place for corrosion is where they place "corrosion protection". Now i know you may say, duh, you idiot these are the places where most exposure, concentration is , etc., but in reality it seems that corrosion protection does a better of not letting water/salt, etc., escape, rather than preventing it from getting in. In this case, personally I would skip the protection of any kind in favor of perhaps a heat shield that doesn't make any contact with the tank. Just my .02.
     

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