Hitchcocks Forum

Hi all. I have a push/pull petrol tap bought from our hosts. The tap is fine, but I have a slight weep of petrol from the thread where it goes into the tank. What is the best way to seal this? Can I use PTFE tape, or will that not work with petrol? Thanks for any advice.

I use PTFE tape, a slightly thicker stuff than that sold in B&Q and so on, I got it from a proper plumber's merchants after advice from a plumber pal! Ethanol in fuel does soften it but if the joint you make is tight enough it won't leak. PTFE is also useful to seal the dripping nut under the front fork legs...
REgards, Mark

Just to agree Std PTFE is Fine & I use it,
.... I did go through a faze of using GAS PTFE (50p more) But did not Notice Any Benefit from memory!....You can get PTFE in all Shapes and thickness ,..I use to use the CM Sq Stuff to Mount Carbs on at one time to the Engine.. Cheers all.

Just make sure you wrap it the right way - so the tape is pulled in to the thread as it screws in. Wrap it rice and tight and push well into the threads

Just taken a look at the type of push pull tap you say you have bought here. It has a short thread which is designed to screw completely up tight to the petrol tank. A normal red fibre washer will seal perfectly as long as the surface around the thread of the tank boss is perfectly smooth and un-scored. You might also try a Dowty washer also sold here...they have a rubber seal incorporated in them to seal against the inner thread, but to be honest in this flush compression joint where no thread is left exposed, a simple fibre washer will work just as well in my experience.

I also prefer to use the Fibre washers but here in South Africa they are very hard and not perfectly flat so I first rub them on fine flatting paper until all the high spots have disappeared and then they normally seal properly without having to over tighten them.

I'll try the 'belt and braces' method I think - PTFE tape and a fibre washer! Thanks for all the advice.

I use Loctite 577 thread sealer. Easy to use, 100 % petrol resistant, and it really works. Check it out here: .-.-.-.-.-.-.-.-.-.-.-.-.-.-.-

http://www.loctite.sg/sea/content_data/93780_577EN.pdf .-.-.-.-.-.-.-.-.-.-.-.-.-.-.-

Regards, Anders F. R.

A cardboard gasket or copper washer would also work.... On a point of order. Ethanol does not soften PTFE. Almost nothing reacts with PTFE, its one of the most inert substances known to man. It's the only stuff you can make a container of to keep hydroflouric acid in.

Stinkwheel, that may be so but PTFE I have used for sealing petrol taps becomes softened to a glue like consistency when exposed to petrol. Maybe it's ethanol or possibly benzine but when used in contact with oil I don't see the same results?
REgards, Mark