going back to plastic! Yes I know its an old thread but I just put some black metal caps on, now I am throwing them away.

 

I have metal ones on my T and always wonder why the threads were plastic, it's all so clear now. Hope it works out for you.

 

I have metal caps.. I constantly monitor my tire pressure do to alot of offroading so I have never had any issues with them.. But if you are a person who never removes them for long periods, I would also suggest rubber or plastic caps... That was a expensive air down for you.. Sorry too hear of your misfortune.