Fuel leak from tank sump

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mach2andy
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#1 Fuel leak from tank sump

Post by mach2andy » Fri Apr 24, 2020 9:03 am

Several weeks after putting some fuel in my tank, I noticed a pervading smell of gasoline in the Jagcave. Looking up at the tank sump, the foam pad that sits under the tank around the boot floor aperture was saturated with fuel. A very nervous feeling pervaded my loins at the thought of having to remove the tank and refit it. I drained the tank & removed the sump and the saturated pad. There was nothing obviously wrong. The rubber seal [a new item from a well known supplier] between the sump and the tank boss was present, and undamaged. But on close examination, the seal was very soft and had obviously expanded. I made a seal from a sheet of gasket material and fitted it with a thin smear of Blue Hylomar and hey presto it's completely leak free. So is it safe to assume that the seal was simply not fit for purpose? Because the seal was soft, I'm assuming that fuel had permeated through the seal causing the leak? But for fuel to come into contact with this seal, it has to permeate up through the threads.
So, perhaps I should have put some sort of sealing medium on the threads when I installed the sump?
ATB
Andy

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Andy
1970 S2 FHC
1965 SB Corvette Ragtop

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mgcjag
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#2 Re: Fuel leak from tank sump

Post by mgcjag » Fri Apr 24, 2020 9:29 am

Hi Andy...worth a read..plus plenty more similar topics below...Steve viewtopic.php?f=4&t=6339
Steve
69 S2 2+2 (just sold) ..Realm C type replica, 1960 xk150fhc

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Philk
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#3 Re: Fuel leak from tank sump

Post by Philk » Fri Apr 24, 2020 4:24 pm

Back in 2018, when I had the mechanical work done on my car, a new petrol tank sump seal was installed. Within a couple of months (and after filling the tank up ahead of a long run), we had a petrol leak onto the garage floor. The culprit (which was also sourced from a main supplier) was the petrol sump seal which had been made out of non petrol-resistant rubber). In my case, it had thinned, expanded and allowed a leak to develop. Replacing with a more old fashioned seal stopped the problem immediately. Two years on and not a drop since.
Phil
1964 S1 3.8 OTS

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#4 Re: Fuel leak from tank sump

Post by mach2andy » Sat Apr 25, 2020 9:00 am

Thanks for your replies, and for the link to a previous thread Steve. Fuel has been in my tank for 5 days now with the new seal arrangement, and the area is as dry as a bone. So hopefully I don't have the porosity problem that others have encountered. My tank has had a beautifully executed repair carried out in this area previously, so I guess that it too had become porous at some stage. With mine and others experience with this rubber seal not being fit for purpose, it beggars the question as to why the major suppliers are still selling them??
Andy
1970 S2 FHC
1965 SB Corvette Ragtop

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#5 Re: Fuel leak from tank sump

Post by mgcjag » Sat Apr 25, 2020 9:06 am

Hi Andy.....have you informed the supplier.....Steve
Steve
69 S2 2+2 (just sold) ..Realm C type replica, 1960 xk150fhc

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#6 Re: Fuel leak from tank sump

Post by mach2andy » Sun Apr 26, 2020 8:32 am

Hi Steve
Yes I have, and they replied immediately asking for a few more details.
ATB
Andy
Andy
1970 S2 FHC
1965 SB Corvette Ragtop

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