Fuel Tank Repair

[LeftAngle]

There was a bit of discussion going on over at the Yahoo site about where the push lines for the fuel tank should go after the originals get closed up to the point they don't pick up fuel anymore.  Mine were closed up solid and no amount of air or digging with a wire could open them up.  The first thing I noticed about the originals was, they were mounted directly to the bottom of the tank.  In my upbringing in design, I learned that fuel lines should NEVER be touching the bottom of the tank, because that's where all the nasties live.  If you're racing your car, I suppose the location of the fuel lines should be where every drop of fuel can be sucked up, but if you're like me and your tanks will be sitting for long periods of time with fuel in them, take heed.

Here's what I did to mine: 

1: Drilled hole.  Large enough to fit a 1/4" line through.  In my case, I'm changing everything over to Navy, so the hole was drilled to the fitting size.  Make sure it's the same height as the original so it misses the frame

2. I bent the line 90º and measured it to sit 1/4" above the bottom of the tank

3. Pushed it through and silver soldered it to the tank.  Brazing should work as well.

4. The AN fitting sticks out a bit further than the original line, so I might have to mess with re-installing it.  If I were simply replacing the 1/4" line, I cut it to length. 

5. I cut and filled over the old line.

6.  I'll be coating the inside with epoxy, so the fuel will never again touch the inside of the tank.

7.  If I ever get rich, I'll pick up aluminum tanks.

Pictures:
1. You can see the old line running through the crud along the bottom to the center of the tank.  The car was sitting in a barn for over 10 years and everything in the tank had turned to concrete.  The new line is to the left and stops about 1/4" above the bottom.

2. The fitting on the outside of the tank.  I haven't measured how far it sticks out. but it needs to slip past the fiberglass that covers the frame as the tank is installed.  If it doesn't fit, the fiberglass will lose the fight:)

Bruce

[EuropaTC]

A neat job, and that proper screwed fitting looks the part.  Given the circumstances of how long the tank's remained unused and no doubt rusting away merrily, the epoxy coating sounds a good move.

Brian

[LeftAngle]

That was the recommendation of the mechanic that first saw it.  Luckily, the tanks are rust-free on the outside and still solid.  The interior sides aren't too bad, but the bottom looks like the concretion alone is adding 5 pounds:)  Be careful where the new fittings are placed.  Mine are slightly lower than the originals, so I may have some fitting (double meaning) issues putting the tanks back.  I wish I had the extra cash to have them powder coated.

[EuropaTC]

Could you dissolve the rubbish that's collected at the bottom ? It might be a combination of petrol residue (the gooey stuff that messes up carburetors left standing) and iron oxide, so some form of gentle rust treatment might shift it for you ?  I'm thinking of a solvent such as petrol or cellulose thinners to get the organic stuff out, then maybe a dilute inorganic acid to see if the iron oxide is willing to vacate the tank ? 

Obviously the acid needs some care, and fairly dilute, but you shouldn't do any major damage if it's only there for a few minutes at a time & then well rinsed clear.  Just thinking about it, you'll probably need something like that anyway before you can apply the epoxy lining ?

Brian 

[LeftAngle]

I'll have to do some more research before making any changes to the inside.  I got the impression the coating can go directly over the concretion, and as long as its self supporting, it makes sense.  As long as oxygen can't reach the metal, it wouldn't be able to cause further damage.  I'm always ready to listen to processes that make things easy.  I forget the name of the product he told me to get, but I'll be talking to him before I get it.  He told me he use it on a MGTD years ago and it's still as good as the day it was applied.

At the moment, this is all hearsay, so stay tuned. 

[andy harwood]

I've got a early Buell RS1200 motorcycle. The bodywork is fiberglass, including the gas tank. When the tank  started seeping, I purchased a KBS epoxy tank kit. The kit comes with a cleaner & rust remover.
I didn't use the rust remover, but the epoxy liner works great. Be careful when stirring/mixing to keep bubbles at bay.
It is a 3 part kit, KBS Coatings.
HTH
andyh

[LeftAngle]

Thanks Andy. KBS sounds familiar.  That may be what my mechanic suggested.