Petrol Tap Seepage

[andrew.johnston]

MkII Sq4 - I have fitted "BAP" type petrol taps from Drags, but am finding petrol seems to be seeping out through the threads of the nuts that hold the petrol pipe to the tap and/or the tap itself to the adapter in the tank. I have tried using the very thin "PTFE Thread Seal Tape", which has worked on other threads before, but it's still seeping. Is there a better sealant to use?

[andrew.johnston]

MkII Sq4 - I have fitted "BAP" type petrol taps from Drags, but am finding petrol seems to be seeping out through the threads of the nuts that hold the petrol pipe to the tap and/or the tap itself to the adapter in the tank. I have tried using the very thin "PTFE Thread Seal Tape", which has worked on other threads before, but it's still seeping. Is there a better sealant to use?

[simon.holyfield]

I had a look on the Draganfly site and see that the BAP tap they sell shows a locking nut. Is that the one you are using? Is it a parallel thread?

[paul.jameson]

You need a smear of Red Hermetite on the threads. Whilst any other gasket sealant will do the job initially, only Red Hermetite resists petrol for the long term. These days it is sold as Red Hylotite or some such name but it is the same stuff.

[andrew.johnston]

Thanks for the advice- I'll check the locknut situation (though the attached petrol piping/nut assembly is also Drags so should be right) and will also seek out some good old red Hermetite - by whatever name!

[allan.walker]

What kind of washer have you used between the locking nut and the tank boss? My go-to type of washer for a leak-proof seal on petrol and oil unions is a Dowty washer (aka Dowty seal.)

"The Dowty Bonded Seal is a synthetic rubber sealing member that is bonded with heat and pressure to a zinc plated steel washer. The flexing action of the lips under pressure provides a positive and leakproof seal against a wide range of fluids, at, depending upon size, pressures up to 20,000 p.s.i. (1380 bar)."
(quote from t'internet.)

[ian williams]

dead easy , just get some loctite 577 pipe sealant and it will sort that .
ian

[andrew.johnston]

Thanks for the extra advice and ideas - I think the seepage is from the pipe joint below the tap, as it only seems to seep when the fuel is turned on - but I'll check again. Will try either Hermetite or Loctite if the seepage is shown to be the tap/pipe joint. If it's the tap body/tank joint causing the leak, I look out some Dowty washers. I just spent a fortune getting the tank repaired/chromed/painted/internally sealed, so I really need to finish the job right!
PS I still remember the smell of using red Hermetite on my very first Vespa in 1964......

[andrew.johnston]

PS - could I use Wellseal? - I have some of that already

[andrew.johnston]

Thanks to all who responded - I have now overhauled the seeping tap/joint using Hylotite, a 'snugger' fibre washer and some thread sealant tape - it now seems to petrol-tight, but won't really know until I'm allowed out on it again. Hope that happens by 6th February, as I will have owned the bike 50 years on that day!