Fuel Tank lifesplan?

I woke up this morning to find a large amount of diesel (brimmed the tank yesterday) all over the road and and persistent large drip of diesel from the fuel tank. I have not yet investigated properly but on a quick look to put a bucket underneath it looks to be from the bottom of the tank (certainly not the fuel sender).
I last replace the fuel tank 9 years ago after dropping it onto a rock (fitted a tank guard at the same time) and replaced with a cheap aftermarket tank. I am aware they rust especially where water site between the tank and the cradle. Does this sound about right for being due to replace again or should I be looking more carefully at any other areas before ordering a new tank.
Cannot afford to take it all apart before ordering parts as it is parked on the road and being in pieces for any length of time upsets the neigbours, but I can order a new tank and when it arrives spend an afternoon fitting.

Never had one of my own rot out, but at work it is not unusual for a ten year old steel tank to start leaking, we do find it more on the vehicles that have been stood for many months.
I am pretty sure they all rot from the outside in, between the tank straps and the tank itself, or a failed weld seam.

On a very quick look that is where this looks to have failed, between the cradle and the bottom of the tank. It is not stood and is a daily drive, but because of that is also gets all of the winter salt every year! Once I have finished work I will have a proper look and see if I can definitively say it is the tank and not a pipe or a union.

I waxoiled my britpart tank when I replaced the old one. Hopefully that’ll give it a few extra years

dag019 said:

if I can definitively say it is the tank and not a pipe or a union.

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Saying that you filled it to the brim, definatley check hoses as I had similar and fond the breather hose had a split
Took me ages to identify as like you thought it was the tank. But only happened when filled right up,

As @Glasgie says, check the jubilee clip where the filler pipe or breather pipe are. If the tanks full it could drip down between tank and guard and appear somewhere else. I’ve also had the steel filler tube rot through before as well

Glasgie said:

Saying that you filled it to the brim, definatley check hoses as I had similar and fond the breather hose had a split
Took me ages to identify as like you thought it was the tank. But only happened when filled right up,

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I have removed what I would guess to be about 3/4 of a tank and it is still dripping consistently so I am leaning towards it being the tank, but I will check the hoses. I have had the filler hose split on the series so am aware of that problem from first hand experience as well

i would give it a good run on some uneven ground and some speed down a main road, could be fuel has pooled and is trapped between cradle and tank.

Run it for a day or two, had to do one on my 110 project, that poured when brimmed rotten near sender, back tanks can be a bu##er to fit on your own. Took 3 of us to wrestle it and the cradle into place and bolt it up and that was on a ramp

My 110 rotted out it's tank on top at about 30 years old, but what the previous owners had done with it I don't know.

Cavey_P38 said:

i would give it a good run on some uneven ground and some speed down a main road, could be fuel has pooled and is trapped between cradle and tank.

Run it for a day or two, had to do one on my 110 project, that poured when brimmed rotten near sender, back tanks can be a bu##er to fit on your own. Took 3 of us to wrestle it and the cradle into place and bolt it up and that was on a ramp

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I did manage to replace it on my own last time, including a very heavy tank guard, strategic placement of axle stands, and a jack allowed me to maneuver it into place, but it is not a job I am looking forward to again.

I also think it is leaking too badly (still) to get away with that, there is a very constant regular large drips I would not feel comfortable dropping that much diesel onto the road, especially in this weather. You stand a watch it there is probably about a drip a second.

Fuel-tank lifespan - How long is a piece of string?

When I bought my 1986 ex-MOD 90 22-years ago I could see that the tank wasn't original and had just been replaced so was in excellent condition. As I was in for the long haul I removed it, cleaned it, primed / painted / Waxoyled it and there it sat for the next 21-years. When I removed it last year it was still perfectly solid. I was fitting a new chassis so it made sense to fit a new tank at the same time so that was treated the same way as the earlier one. Lets see how long this one lasts.
Fully agree about the filler pipes though (both the steel & flexible ones), I had to replace the steel pipe on mine last year and it was only 34-years old! The flexible one looked like the original but was also replaced at the same time just in case.

Well I have been out and had a look. The filler is dry, the sender is dry, and from
What I can see the return pipe At the top and front is also dry. So looks like it probably has rotted the bottom out. Annoying as I did paint it before fitting last time round. This time I might just cover it all in wax oil as I cannot have it off the road long enough to give it a few coats of Paint.

dag019 said:

Well I have been out and had a look. The filler is dry, the sender is dry, and from
What I can see the return pipe At the top and front is also dry. So looks like it probably has rotted the bottom out. Annoying as I did paint it before fitting last time round. This time I might just cover it all in wax oil as I cannot have it off the road long enough to give it a few coats of Paint.

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@dag019 , you may like to use Raptor paint [truck bed liner] on the new fuel tank rather than std paint, it's far more durable + once thoroughly dry, to run a bead of black RTV sealant around the edges between the cradle and the tank - this means no crud/water can collect between the two layers of steel and the drain hole acts as a drain hole. Raptor is available in cans so the inner areas can be sprayed too.

https://www.u-pol.com/uk/en-uk/prod...ive-coating-uk/raptor-2k-aerosol#.YBvEXej7RPY

Raptor is far more effective than a moisture absorbing / moisture trapping Waxoyl

dag019 said:

On a very quick look that is where this looks to have failed, between the cradle and the bottom of the tank. It is not stood and is a daily drive, but because of that is also gets all of the winter salt every year! Once I have finished work I will have a proper look and see if I can definitively say it is the tank and not a pipe or a union.

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Gasker on sender/gauge or the return pipe assy?

Edit, igneor that, just seen you have already checked them!