Hey nomad,
Sounds like you really have a high mileage unit there. I completely understand your reluctance to give up your old friend.
For a repair, in lieu of popping the end cap, the first thing that comes to my mind after reading your post is to use a length of *heavy walled heat shrink tubing* over a majority of the barrel length. Make sure to position the shrink tubing so it extends past the end of the probe before shrinking. This will allow the end to be trimmed with enough length remaining to firmly apply some good old J-B Weld over the end and then molded/shaped as needed, preferably before it hardens.
eBay is
*one source* for heat shrink tubing. I would wager a guess 3/4 or 1 inch,
*heavy walled*, tubing with a shrink ratio of 3:1 would be a good choice.
As an added suggestion if you choose to continue with this idea you might want to use some dry silicone spray on the Tec's barrel length and its end before starting. Doing so
should allow the heat shrink tubing and J-B repair to be removed (pulled off) if desired.
It's anyones guess as to how long such a repair might last and I would assume you would lose some of the probes sensitivity.
If you get cold feet, I highly recommend the Garrett Pro-Pointer. I just purchased one and will find a freshly buried nickel at a measured 1-1/2 inches in my coin garden.
And I have some bad a$$ ground.
Good luck and HH