When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
No to the Teflon tape. Put a touch of anti-seize between/under the nut and the line (not on the sealing surface) and on the threads to aid in future disassembly.
Is it a good idea to put a thin wrap of Teflon tape on fittings like power steering hoses, transmission lines into the radiator etc?
The tape only has a positive function if you are careful to put it only on the threads and under the nut. There, it helps clamping force to give you a better seal. If you get any on the sealing surface, it may interfere with a good seal.
Think this through. The seal is made on the flare, as shown by the red arrow. If you need to put teflon tape or other sealer on the threads, what prevents a leak between the flare nut and the tube (yellow line)?
One thing you SHOULD do on flare nuts is to apply a very small amount of anti-seize to the tube where the flare nut sits and to the threads on the flare nut itself. Do not get any anti-seize on the sealing surface of the flare, however.
Makes sense. If the flare wasn't properly "seated" the only thing the Teflon might do is stop the leak from showing on the outside. Correct?
Also, isn't there several types of antiseize. Some more easily "broken free," than others?
Ahhhhh. I see what your saying. So the method here would be to to advance that flare into position and make sure it's "seated", and THEN thread the nut.
My engine guys turned me on to Teflon pipe sealer used by plumbers on NPT connections. Available everywhere plumbing supplies are found. When tightened you can wipe the excess off for a neat clean look, no ugly white tape showing.
[QUOTE=Also, the Teflon is to lubricate the threads, not fill the gaps.[/QUOTE]
I think the teflon can be useful to block the infiltration of undesirable moisture into the thread area especially in rust belt states, but maybe not so much on hobby vehicles.