Pesky fuel tank drain plug leak...

[mac73s]

72 T - new tank (800 miles ago) and using an aluminum washer on the allen head drain plug. I have never been able to get a 100% leak free seal and seeking a solution. My 72/73 parts book is unclear, but I recall that the 'sealing ring' is a dark red/maroon fiber washer but I thought the aluminum washer would be better...perhaps not given my experience. Thoughts would be appreciated on what is best, and is there a sealant that I could use in combination with either washer to help the seal. I only want to do this once...pain to siphon out the gas, etc. Thank you!

[NZVW]

PTFE Teflon tape is both oil and petroleum resistant due to its chemical inertness so form a length of PTFE tape into a thin length unwind the drain plug and wind the tape between the aluminium washer and the tank about 6 times. Only unwind the plug about 1/8" so if your quick you wont need to drain the tank.

[edmayo]

My experience with a repro tank,,,,if that is what you're using, was that the seal surface wasn't perfectly perpendicular to the plug threads. I put dye on the surface and lightly tightened the plug, it didn't wipe all the surface.

[NZVW]

Ed is correct on the fact that most people over tighten anything pertaining to seal surfaces regarding fluids.
Being a plumber I would have just wrapped hemp around the thread and never checked it ever again.. but PTFE Teflon tape is soft and will seal uneven 'faces' on the proviso that you do NOT over tighten

[62S-R-S]

A cumbersome idea that should seal for you : scuff sand outer area, apply skim coat of jb weld on circumference. Strong light available, to elevate a chunk of alum to rotate-sand as perpendicular as the eye allows. Die test..choosing a hard fiber washer afterward, to prevent gouging.

[mac73s]

Thank you all for your thoughts and suggestions, but a few follow up questions please: Is there a consensus as to whether the fiber of aluminum washer is better? Re the idea of backing out the drain plug by 1/8th inch and applying the PTFE tape, I assume if it is already slightly and slowly leaking that backing out the drain plug even that little amount it is going to leak further...can the PTFE tape be wrapped around a wet fitting?

[lopena]

Mac73s:

Yes, white Teflon (PTFE) tape can be wrapped around a gasoline-soaked fitting.

As NZVW warned above, don’t overtighten the fitting after you wrap it...that will tear and shred the Teflon tape.

Good luck...


Alan
N.J.

[62S-R-S]

With the tank out..it's 10x's easier result.