>PTFE Tape or Dope on NPT DRAIN plug threads?

[fixizin]

What say ye, RKIs? Looks like there was dope/compound on there from the factory, and I know to NOT use the white (single density) tape on a fitting > 3/8", but instead use the pink (double density) or yellow (triple-density) tape... OTOH I also have some Oatey "Great White" pipe dope on hand... hmmm...

 

[RonD]

teflon pipe tape is used to lubricate pipe threads not to seal them, although it can help seal them

On "senders", one wire type, the metal threads are the ground point for the sender, so a few threads need to be left bare for a good ground

Two wire senders, or sensors, don't need bare metal on the threads they have a ground wire

 

[Curious Hound]

On a drain plug, I sometimes use a little dope. Or tape. Or nothing.

As Ron mentioned, tape is not "meant" to be a seal. It helps lubricate the threads to prevent galling. Dope is the sealant. But, if the threads are in good condition, nothing should be needed. The male and female threads are tapered. So, as the plug is turned, the threads automatically form a tighter seal.

Don't overtorque. You can break stuff. I cracked the boss around the (I believe) fill plug on the transfer case of my 88 F150 many years ago.

 

[RonD]

For drain plugs copper crush washers are relatively cheap and work great

 

[Curious Hound]

For drain plugs copper crush washers are relatively cheap and work great

That would be for parallel pipe threads like the typical engine oil pan plug.

 

[fixizin]

What IS the TORQUE spec for ye olde BW-1354 plugs? As usual, lamer-Chilton's and lamer-Haynes are mute on the issue...

 

[Curious Hound]

What IS the TORQUE spec for ye olde BW-1354 plugs? As usual, lamer-Chilton's and lamer-Haynes are mute on the issue...

3/8 npt (national pipe tapered)

 

[19Walt93]

I use Permatex thread sealer because I don't like teflon tape.

 

[fixizin]

Thanks Ranger Gang!

I think it's more like 3/4" NPT fitting than 3/8", but since I'm thumb-palming a small 6" ratchet I think(?) I'm safe from over-torque...

... since the 'Great White' compound said it's good even for steam, acids, and caustics @ 600 PSI(!) I McFigger'd that's good enough for ATF @ 0.2 PSI!... lol.

Schmeared a bit on there, ended up with just a small peripheral bead that squeezed out, no leaks after 2 whole hours and 8 whole miles.

Fill plug had nothing in the threads, and never leaked, so just left it nekkid, for easier checking. Still, gotta wonder about taking this tapered-thread scheme--originally intended for iron-on-iron and brass-on-brass plumbing fittings--and using it for steel-plug-on-cast-aluminum xfer cases...? Oh well, millions and MILLIONS of 'em out there, making the world a better place by spreadin' the torque around!

PS: @ 80k miles, xfer case fluid still nice and red... M5OD fluid, NOT so much... ugly dark gray, no bad smells though, "flushed" it with almost a pint of new stuff that came out red and clear... "mos' def" shoulda got after it back at 60k... fingers crossed.

 

[Curious Hound]

Pipe size is measured by inside diameter. So a 3/8" pipe (or plug) is nearly 3/4" in diameter on the outside.

And, in case you're interested, tubing is measured by outside diameter.

 

[fixizin]

Plumbers & Pipefitters B sneaky that way! But their UNION has made some very savvy investments on the beachfront in Hollywood, FL!