Water in Fuel Tanks

[Dilkris]

So what's the long term solution for water sitting on top of the tanks? I guess it either:-
a) - stop it from getting there or
b) - modify or adapt the top of the tanks so as it doesn't matter and it can run off. Yes?
Anybody got a quick and cost effective solution that works? (No - I don't want to buy new aluminum tanks      

[EuropaTC]

After reading this thread I would imagine that just painting the tank tops with Waxoyl or something else that won't dry out would be good enough. I wonder if this isn't a problem for cars that have stood for years and not those in regular use ? The reason I say that is because the tanks on my car failed at the bottom with corrosion on the lower seam/leaks, not the top. 

When I bought it in the 80s it had only stood for a year after the first owner had died, until then he used it regularly from the records he kept. I think if water was collecting there and you were using the car daily then you'd find it before it became a serious problem.

[4129R]

I have no idea how this hole appeared after I checked both tanks and fitted them just over a year ago.

Due to the lip around the tank top, any water getting on to the top would find its way into the tank and prevent petrol getting into the carbs.

[Dilkris]

My tank suffered most corrosion around the sender locating area - I had to completely re-work this as the locking ring set up was completely unsalvageable.
Note the photo shows a blanking plate where the sending unit is mounted - I was preparing here to treat the inside of the tanks. 

[BDA]

That looks like a nice treatment on your fuel tanks!

[Dilkris]

I wonder if this isn't a problem for cars that have stood for years and not those in regular use ? The reason I say that is because the tanks on my car failed at the bottom with corrosion on the lower seam/leaks, not the top.

I think you have hit the nail on the head - with regular use, any moisture that reaches the top of the tanks is either removed via heat from the engine plus any circulating air.   

[Pfreen]

Mine failed from water on top which came through the trunk lid screens. My solution was to install aluminum fuel tanks and seldom leave the car in the rain.

[4129R]

New ally LH tank arrived the next day from SJS. The 4 bolts holding it in place have to be changed from 1/4" UNF to 6mm metric. Otherwise it went straight in after the rear was jacked up high enough.

BUT

There has always been a smell of petrol in the garage which I attributed to me draining both tanks regularly to remove water.

When draining the RH tank, there was petrol all around the brass drain plug. I had fitted a new fabric washer when I last tightened the brass drain plug but still petrol was dripping very slowly from the area.

It turns out that there is a hairline crack where the ring the drain plug screws into. It seems by constantly undoing and tightening the drain plug, I have caused the ring the leak where it is presumably braised to the steel bottom of the tank.

Another new ally tank needed, this time for the RHS.   

[4129R]

I wonder if the "turret" where the fuel gauge sender is located, is to allow a longer arm for the float.

I measured the arm which came out, and it was longer than the width of the tank, so I couldn't work out how it didn't hit the other side of the tank. Then it dawned on me just now that the sender is located in the power bulge turret.

[Dilkris]

And those tanks are not cheap - I feel your pain.