Tire valve extender

If you must use extenders, make sure you only get ones that are the 'airless' type. Meaning, there is no air pressure in them, except when you put a gauge or air hose on it. That way, there is no risk of your tire leaking air if the extender works loose (because they can and will).

Any other kind of extender that has air pressure in it all the time, and you are asking for trouble, IMO. Been there, done that - Had one of those extenders knocked loose by road debris and leaked out all the air in the tire. Almost cost me a tire, had I not caught it quickly and taken care of it (thank you, Good Sam Roadside service!!)

A much, much better solution, is the complete replacement vales, dually valves, like already mentioned. More expensive, and more work to install, as tires have to be dismounted since its a complete valve stem replacement. But, they make checking, topping off the tires much, MUCH easier, both inner and outer. I have the dually valves, and I can check, inflate ALL the tires on MH and all our other vehicles with the same, simple digital tire gauge. No need for a special truck tire gauge. And, I never have to worry about a valve stem leaking ever again. :)

I would not use any locking material at all.

The problems I've had with extenders were all installation related.

They need to be installed tightly.

I had rubber extenders that were nothing but problems. I got rid of those and got some good quality stainless steel braided extenders and so far, no issues!

Look into just having dually valves installed about 110.00 but worth the money and you don't have to worry about leaks.

two important things about these, one buy good ones the other is the installer. six months back I had new tires put on and new extenders. went out to check air before a short trip , and could not get a reading on the inside duels. took to a local shop ,they called me at home and wanted me to come to the shop, showed me both inside extenders twisted to fit threw the holes. they put new ones on and remounted the brace that holds them. other shop gave me my money back .

Not sure about Lock tite but spend good money and get good extenders. I have had 3 go bad in 2 years. They can cause a slow leak. If it weren't for airing up and my TPMS I wouldn't have them at all.