Fuel tank pinhole - replace or repair?

Opened the garage this morning. Strong fuel smell. I see some bubbled paint on the fuel tank. I wipe with a rag. Paint comes away and a pinhole is revealed - and starts a stream of fuel out of the tank.

I’ve drained the tank (petrol). The hole is tiny -literally a pinhole.
Do I use some fuel safe epoxy of some kind to patch - and if so recommendations for a good product very gladly welcomed.
Or replace at approx £110?

It’s petrol, 1980, original tank. Some sediment.

Thanks!

Speedy6111 said:

Opened the garage this morning. Strong fuel smell. I see some bubbled paint on the fuel tank. I wipe with a rag. Paint comes away and a pinhole is revealed - and starts a stream of fuel out of the tank.

I’ve drained the tank (petrol). The hole is tiny -literally a pinhole.
Do I use some fuel safe epoxy of some kind to patch - and if so recommendations for a good product very gladly welcomed.
Or replace at approx £110?

It’s petrol, 1980, original tank. Some sediment.

Thanks!

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Fairly common on older vehicles, mild steel doesn't last for ever.

Personally, I would replace the tank. If you want to run it for a while at low cost, push some well chewed chewing gum firmly into the hole, it is resistant to petrol.

Could you get it welded up? though given the hassle factor a new one might be easier.

Steam cleaning first would be necessary to remove the explosion danger from the welding.

I've used good old Araldite to get me home with a leaky tank but that was a temporary patch that was only in place for a week. We were at the bottom end of Italy on a schedule at the time so didn't have much choice.

Don't bother trying to fix the hole, more trouble than its worth cos if there's one hole there's probably loads more waiting to appear.

While I agree with all the answers above. You could drain it and plug it with JB-WELD.
Many years ago I remember my father using araldite and a self-tapping screw to seal a pinhole in the petrol tank of his VW beetle.
JB Weld is pretty good stuff and impervious to fuels.

Blind pop rivit it.

I used Petro-Patch many years ago. It lasted forever.

Thanks everyone for the input.

I’m going to try a fix with some sort of gunge. I’m working on the basis that I’ll be replacing the tank but it’s worth trying as well as getting the experience of whether a fix is doable.

Cabbie said:

I used Petro-Patch many years ago. It lasted forever.

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Good stuff that ...

Speedy6111 said:

Thanks everyone for the input.

I’m going to try a fix with some sort of gunge. I’m working on the basis that I’ll be replacing the tank but it’s worth trying as well as getting the experience of whether a fix is doable.

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Gunge available in most auto factors or Halfrauds ...

Of course if you do get a new tank you do know it probably won't fit

@Rodeo Joe - won’t fit? Aren’t the new tanks just patterned on the old ones? What am I missing here?

I'd try the cheap bodge first. Sometimes they just work and last 'forever'. Replace if not and you've lost pretty much nothing in the process.
I had a leaking core plug in an old Rover P4 once. I plugged it with a slightly smaller core plug and that metal putty stuff as a temporary fix. It stayed like that fine.

Speedy6111 said:

won’t fit? Aren’t the new tanks just patterned on the old ones? What am I missing here?

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Well there have been numerous discussions about the fit of SWB tanks and at every opportunity I mention the fact that I had to cut a lump out of the tub to get mine to fit. Its the filler thats the problem.........

Thanks @Rodeo Joe. I guess I’ll cross that bridge when I come to it.

I’ve got and applied gunge:


We shall see whether it works. It seems a lot like JB Weld, but thicker.

Its worth speding some time cleaning up and throughly wire brushing it. Uusally they rot in an area and the pin hole is the first to go. You want to find the edges of the sound metal, its very annoying to fix one holee and have another appear right next to it, better to put a larger patch on. I like acid flux a blowlamp and soft solder, once you get it clean you can flow it over an area, you can sweat on copper patches too. Obviouly this takes a lot of care but I share the view that the orginal tank fits and if the thin part is small its worth saving. My rear axle cover is a mix of badly done brazing (probably by a squaddy) some soft solder (me) and some plastic metal (me). Its done 5000 miles without a drip.

I remember soft soldering a copper patch over a pinhole in petrol tanks with good success but I didn't like to mention it in case I got shouted at for promoting a dangerous practice. You will need a pretty big soldering iron to get the heat into the tank and a generous helping of common sense to avoid explosions, well, there should only be one - explosion that is.

Extreedoc said:

I remember soft soldering a copper patch over a pinhole in petrol tanks with good success but I didn't like to mention it in case I got shouted at for promoting a dangerous practice. You will need a pretty big soldering iron to get the heat into the tank and a generous helping of common sense to avoid explosions, well, there should only be one - explosion that is.

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Thank you for the clarification about the number of expected explosions...;-)

I’ve heard lots of horror stories about using heat/soldering/brazing/welding fuel tanks. It’s frustrating - my welder is 4 feet away and would deal with the problem in .5 seconds. Granted, there would likely be a whole new set of problems afterward.

Fingers crossed the gunge sets up overnight and I will report back.

I have seen video of a tank being soldered with a blowlamp "in the field". the guy put a rag in the filler cap, lit it, then worked on the tank. I wish I could find the link now. I think it must be the same principle as the flare stack at a refinery, so long as the gas is burning it cannot build up an explosive mixture. Not that i would ever try it!

As we all know, it's the vapour that burns not the liquid. I've seen old timers braze petrol tanks with gas torches, they always filled the tank to the brim so that there wasn't any vapour in it. It's not a practice I would recommend, or even try myself but it is doable.

Col