Leaking Petrol Tank

Hi. I've made three attempts at writing in the 'Introduce Yourself' section because I've not been here for about 18 months. I found this website and forum shortly after buying my distinctive, non-original painted yellow-roofed Wolseley Hornet in the Spring of 2011. Unfortunately by the Autumn of 2011, I was disillusioned with the whole classic car scene (not for the first time) because of defects I'd found with my car that I think really should not have been present in a dealer-supplied classic car, but I'd found out too late to have any comeback. The Wolseley was my first purchase from a 'proper' classic car dealer after a string of unsatisfactory cars bought privately. Now I wouldn't touch the guy I bought it off with a very long barge pole. Anyway I still own the car and with winter finally over, I'm embarking on a measured spending programme to improve it, while at the moment not being that bothered about when it gets its next MoT and gets back on the road.

As regards my 're-introduction' attempts, twice I waffled on too much and I deleted wot I wrote, then last night I wrote what I though was a suitable bit of script, and then my browser crashed and I lost the lot. So I've given up on that. I've started to feel like I'm stuck in 'Groundhog Day'.

So, to the petrol leak in the title. Mainly I am interested in seeing if anyone else has had this problem, although if anyone has got 'fix' suggestions of course I'd love to know. Meanwhile at the moment I'm trying to purchase some Viton sheet to make a gasket that is hopefully fuel resistant. Allow me to explain. Basically when I bought my car I quickly discovered that fuel was seeping past the gasket where the fuel tank sender is mounted, on the side of the petrol tank. Naturally when I picked the car up from the dealer, it didn't have much petrol in it and I had to fill up. Subsequently I bought a new cork gasket from one of the Mini spare parts suppliers, and thinking I was doing a 'belt-and-braces' job, even smeared the mounting faces with a little Hylomar Blue, which is claimed to be fuel resistant. The leaks appeared to stop but there was always a fuel smell in the boot of the car, though now much reduced. Now having liberated the car from a Permabag where it has spent the winter, the expected smell of petrol when the bag was unzipped was particularly strong, and it didn't take me long to find a little puddle of petrol under the spare wheel again, leaking past the same gasket I replaced last year and apparently even seeping through the mounting screw holes. I'd used POR15 fuel preservative over winter and as per the instructions on the bottle, filled the tank up to (I think) reduce condensation in the petrol tank. Clearly an empty tank would now seem to be the better option.

I am of the opinion that ethanol in the petrol has attacked my new cork gasket, and was probably the cause of the original leak. From reading some Vintage Motor Cycle Club magazines I've heard of some of the problems the classic motor cycle community are having with ethanol and I've read that cork shrinks in the fuel. The trouble is, only a cork replacement gasket seems to be available commercially. Prior to the Hornet I owned a much cheaper Mini that had been fitted with a mid-80s plastic fuel tank and I know this did not leak or smell, but I understand the Hornet/Elf fuel tank is unique and can't be replaced with a Mini fuel tank. This is why I'm trying to get hold of some Viton, which is supposed to be impervious to ethanol, but it is quite expensive stuff to buy in standard sizes just to make a small gasket. I do believe I am experiencing my first, first-hand issue with the effects of modern fuels rather than just reading about it second-hand.

Anyway, if anyone has experienced a similar problem or has come up with an effective solution of their own, I'd appreciate hearing about it.
Regards, Mick.

An odd one to me, this, as it's something I've never experienced on any of my many Minis (never heard of one having a plastic tank either!) I did have a major leak once when the tank exit pipe split but that was a realively easy fix (not so getting the petrol smell out of the soaked rear seat squab!)

Anyway you're not far from me, and I work quite close to you, in Ilkeston. Admittedly all my cars have had the later-style locking ring tanks - I assume yours has the screw-in type? The same gasket is used on the estate, but being top-mounted it doesn't tend to give trouble there.

One thing I'd suggest is to drop in to see my mate Daps at Surf Blue Garage at Giltbrook, not far from you. I'm sure he and Les can come up with a solution between them.

Hi MickD - Well I have experienced a similar fuel leak - again from the sender unit on the side of the tank.
The car in question, though a 1965 Mini Cooper - like your experience - only presented the petrol smell in the boot & in the car
when I finally decided to fill-up its tank for the first time.
I purchased a cork gasket from Minipares and fitted it to the back of the sender unit. The leak stopped for about 2 weeks but then
started again. It appeared to me that petrol was leaking out through two of the bolt attachment points (the two lowest holes).
I asked around among Classic car buffs here in Dublin and was advised to use a sealant called STAG. I tried without success to source
the STAG product but no one had seen this product for years !. Finally a friend who restores classic motorcycles amazed me by
suggesting that I use SOAP ! He informed me that soap forms a usually reliable barrier to petrol. So I tried it by starting afresh with
yet another cork gasket. Only this time I coated the gasket with soap that I had first softened to a consistency slightly softer than
putty. I applied a thin coat to the gasket - fitted the gasket - reattached the sender plate to the tank & left the job overight to dry.
It worked - no leaks since - that was 3 years ago & incidentally the car has been extensively rallied over that period - still no leaks.
David2010

asahartz wrote:An odd one to me, this, as it's something I've never experienced on any of my many Minis (never heard of one having a plastic tank either!) I did have a major leak once when the tank exit pipe split but that was a realively easy fix (not so getting the petrol smell out of the soaked rear seat squab!)

Anyway you're not far from me, and I work quite close to you, in Ilkeston. Admittedly all my cars have had the later-style locking ring tanks - I assume yours has the screw-in type? The same gasket is used on the estate, but being top-mounted it doesn't tend to give trouble there.

One thing I'd suggest is to drop in to see my mate Daps at Surf Blue Garage at Giltbrook, not far from you. I'm sure he and Les can come up with a solution between them.

Hi. I felt sure the Mini 850 I owned had a plastic tank from a mid 80s Mini Mayfair, but I may be wrong. It was a large capacity one anyway. That car has gone now so I can't check my information. It didn't leak anyway so I probably paid it scant attention! I just know it took up a lot of the boot, and wasn't painted gloss black like the petrol tank in my Wolseley Hornet so my mind's eye keeps telling me the dull black finish was moulded plastic! I did pay a brief visit to Surf Blue, probably in 2011, after finding their name recurring on forums and lists of Mini specialists, just to size them up and see if I could find them. A bit off the beaten track I'd say! Yes it may be worth paying them a visit if I can't come up with a solution.

David2010 wrote:
Hi MickD - Well I have experienced a similar fuel leak - again from the sender unit on the side of the tank.
The car in question, though a 1965 Mini Cooper - like your experience - only presented the petrol smell in the boot & in the car
when I finally decided to fill-up its tank for the first time

Well David, don't take this the wrong way, but I'm really pleased your fuel tank leaked like mine because now I know I'm not the only one who has a car that does it! I have to say the soap idea sounds really odd and I would never have thought to try it. I suppose soap is basically just fat, and to be honest I wouldn't be able to predict how that would react to modern fuel, but it is an interesting idea and I might give it a go. Thankfully the cork gaskets Mini Spares sells aren't expensive. When I first uncovered my car after winter storage and found the new fuel leak, I thought some petrol was seeping past the studs that the fuel gauge electric wires fasten to, which would be a whole new problem, but subsequently when I've looked I think the fuel had run onto the studs from the flange mounting screw heads higher up. I need to buy a jerry can and syphon pump so I can empty the fuel out to below the level of the sender unit before I do anything else.

After all the fuss certain classic car publications have made about ethanol in petrol and how it can damage old vehicles, I did wonder if it was all scaremongering as I'd never knowingly experienced any negative effects, but I feel sure this gasket leakage must be the result of ethanol because presumably these Minis and their derivatives ran for years with cork gaskets on the tank senders with no ill effects. I'm just surprised more people haven't experienced it.

Mick

MickD wrote:
I did pay a brief visit to Surf Blue, probably in 2011, after finding their name recurring on forums and lists of Mini specialists, just to size them up and see if I could find them. A bit off the beaten track I'd say! Yes it may be worth paying them a visit if I can't come up with a solution.

Yes, Surf Blue is well hidden (though I hear today that they're moving to a new unit up the road), but once you know where it is, easy enough to find.
Daps the owner is my daughter's boyfriend's best mate, so almost family to me, but they do know Minis!