11 replies to this topic

[mbolt998]

'79 Mini 1000, not run for 23y. I took out the fuel tank, cleaned it inside with a hose a few times, let it dry, put it all back in the car, put some fuel in (2 gallons) and nothing comes out of the pipe out the bottom! Took the petrol back out, removed the tank again, and I cannot blow air into the tank through the exit pipe. Something appears to be blocking it.

 

I shoved a bit of wire down it and it just stops. Then I took out the fuel gauge sender for a closer look including with an endoscope. It seems the exit pipe is connected to an internal tube which goes to some kind of pickup (presumably at the lowest point of the tank).

 

The tank itself appears to be made in two halves which are crimped together in the middle and then presumably brazed for a fuel-tight seal? There isn't any way of disassembling it that I can see to get at that internal pipe.

 

Any tips or clues as to what might be going on here or suggestions for how to fix it before I fill the tank with water and then cut an access hole in the side of it (which I will TIG shut again afterwards)?

[Chris1275gt]

In all probability it’s got a fine mesh filter on the outlet pipe like mine had below see if if you can get it off through the side tank sensor hole.

Attached Files

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[mbolt998]

Thanks! I'll see what I can do before getting the angle grinder out... I thought I also might try filling the exit tube up with acetone and standing it all upside-down in the hope that it will dissolve whatever it's gummed up with (presumably the waxy slime that old petrol seems to turn into).

[Ben_O]

Last tank I had with this issue ended up being scrapped and replaced.

[Chris1275gt]

Thanks! I'll see what I can do before getting the angle grinder out... I thought I also might try filling the exit tube up with acetone and standing it all upside-down in the hope that it will dissolve whatever it's gummed up with (presumably the waxy slime that old petrol seems to turn into).

I had to replace the tank as pinholes the filter pictured is after I removed it and tried every possible substance to try and clean it but nothing would touch it.

[Spider]

I have found the oulets are straight, I can usually get something in there, like a 3/16 steel rod and if need be, give it a belt with a hammer. That's also how I deal with the silly filters they fitted.

[Tornado99]

There is a video on Utube of a builder clearing the pickup tube of a tank that had been coated with a tank liner product, which also effectively plugged that fuel pick up mesh. He used an old speedo cable inner core, sharpened the end going into the fuel pickup tube, and spun it using a power drill, thus making an auger to tear away the mesh.

 

EDIT: Here is the viddy:

 

Edited by Tornado99, 23 April 2022 - 11:14 PM.

[mbolt998]

Update: Thanks for all the tips. I put a thicker piece of wire in there (3/32"), as suggested, and gave it a bash with a hammer, pulled it out again, and repeated a few times. Success! The exit pipe now flows freely.

 

One of the things I love about Minis is that whenever you solve a problem you find another one. Filling the tank up with water, and expecting it to leak around the seal where the sender goes in, I actually found it leaking from somewhere else:

 

 leak.jpg   47.9K   0 downloads

 

Clearing up some of the paint and rust from around that sender-gauge attachment point, it turns out it was spot-welded on. Hard to see how spot-welding a flange like that is expected to be fuel-proof. Maybe that's why everything I put in the boot used to come out smelling of petrol now I come to think of it.

 

 spot-weld.jpg   65.7K   2 downloads

 

So I cleaned it up carefully with a Dremel and TIG brazed it. This should improve my mpg, and I can tick "welding on a fuel tank" off my bucket list. It didn't explode.

 

 fixed.jpg   76.75K   1 downloads

 

Not leaking from there any more. But the actual rubber seal is leaking after all it turns out (when you put more water in the tank). Nothing a bit of blue hylomar and/or a new seal won't fix though! I wonder what else this tank will have in store for me.

Edited by mbolt998, 26 April 2022 - 02:16 PM.

[sonscar]

The spot welded bit is not the seal.It is to hold the sender and rubber hard against the tank using the wedge action.The rubber presses against the tank itself.Steve..

[mbolt998]

The spot welded bit is not the seal.It is to hold the sender and rubber hard against the tank using the wedge action.The rubber presses against the tank itself.Steve..

I was wondering about that. Yes it looks like there's basically a hole cut in the tank for the sender, and then there's that sort of cowl which is spotted on. Nevertheless, my tank was leaking from under those spot welds. It was probably leaking through the rubber first, and then under the flange. So basically if I'd just fixed the seal itself it probably wouldn't have leaked. And all that brazing was completely unnecessary. Nevertheless it was fun and at least I haven't actually ruined the tank :)

[Spider]

Very neat brazing !

[mbolt998]

Very neat brazing !

Thanks! It turned out all right even if it was completely unnecessary :) Another "that time I was an idiot" story to add to my collection.