Breitling rep stem tube

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I have a Breitling Bentley rep and the crown just barely engages the threads on the stem tube. I have taken the o ring out of the base of the crown to get it to engage but would like to replace the stem tube. I think its screwed in but not sure, measures about 4.2mm to 4.22mm od of the treads and only protrudes 1.5mm. There is an o ring in the stem tube at the outer end and I believe also the inner end. Looks like a torx screw with the o ring out but it doesnt fit the sizes I have. I am mechanically inclined but a newb in watch repair. Questions are

Where can I get parts I have only been able to find Rolex stems which thread in I assume this one also threads in if so is it right hand or left hand and will it require heat to get it out. ie likely to be loctite etc on it.

Can I use a Rolex stem, if so which one should I order.

thanks