bought a tank the other day, but i cant work out what i need to do to stop fuel leaking out of the thread where the outlet screws in. its like a normal 8mm outlet, but it can be unscrewed (presumably to allow a 10mm one to be used).

does anyone know how to make it fuel tight? PTFE?

its a viper tank, but he's not been online in a while to answer!

cheers.

I would imagine that PTFE tape would do, however i don't know how it reacts to petrol. Other options maybe to buy loctite thread seal, now comes in a 'prit-stick' type tube. Or maybe silicon sealent. Again I don't know how this would react to fuel.

Hope this helps,

Andy

I also bought a tank from Viper, excellent quality.

I sent a U2U on 25th Jan asking same question, sealant or not? to date, he's not read it.

I have a feeling the threads are tapered and they should be just tightened, but want to be sure.

Joel, are you saying that yours actually does leak? or are you just thinking it might, without sealant?

JohnN

I used PTFE tape to seal the threads of the bolts ,when I fitted my fuel pump in the bottom of my fuel tank,I did think myself it may have reacted to the fuel but no leaks yet 9mths later.
cheers Paul

john, i havent tried it yet, just wanted to avoid the possibility of a petrol leak. its an awesome quality tank though!

so i reckon its PTFE time then! i can finally get the beast running again!

cheers for the thoughts guys.

ps, anyone seen viper? he said he had a lot of work on...

Unscrew and coat the treads with "lock&seal" --- of course this assumes it isn't designed to seal with a fibre or copper washer

Don't use any silicone sealant near a tank.

The stuff pills up and 'jellifies' and is not good for petrol anyway.

PTFE tape is best , it's fuel resistant.

If the thread is NPT then some form of sealant is required. If it's NPTF then it doesn't - that thread shape is designed to deform and make a seal.
(Guess who was looking this up last week )

David

A word of warning about sealant. My neighbour built a new tank for his vintage car. Fitted the level gauge with instant gasket. He put too much on and it 'squelched' inside. It went hard but was thin where it was nipped up. Eventually it broke off (several bits iirc) and caused havoc with his fuel lines / filters etc.

I would hate anyone elst to go through what he did.

IHTH
Darren.

I used brass taper threads with a wipe of blue hylomar (petrol proof). No signs of a leak after 6 months with fuel in the tank

If the fitting has a shoulder, then use a fibre washer.
National threads need a sealer (used to be jute) and the newer taper fine are definitely gass tight.
I use NPTF with no sealer or tape: keeps it simple and nothing can break away and clog other components.
I would imagine Viper would have used NPTF, but as I haven't seen his tanks, I could be talking ballox.