A pin dropped out my 450 dozer....??Track & bushing Ques

[Jeroen]

Hello, hope someone can shine some light on a mystery. Raking up the last track marks we found a pin, clearly a JD pin about 1 inch diameter and about 3,5 inch long, yellow paint on one side, zero wear marks on it and no holes or thread to keep it in place. Spent about an hour under looking with a lamp, looking at my book but can't make head nor tail out of it.

Any ideas???

Does anybody has experience with "self made" bushings? my dozer is from about 1969, got it prety cheap, but the previous owner didn't know you had to do some maintenance sometimes.......hence the fact that I need to chance about all the bushings, looking at prices and the amount I need I was wondering if I would go to my local workshop, they could turn and machine about everything, they repair Hydraulic pistons, and have about everything in stock. But how do you know the right measurement? And do you need hard or soft steel for wear parts?
Or is there someone who will sell a complete bushing kit with a fair amount of discount......?
The play is so bad that the track rubs against the left angle piston, so can't wait much longer...
The tracks are worn as well, so next question, since I'm in Europe I can't just ship tracks from the US, (better get a brand new dozer) so if I would be looking at new or second hand chains, are they the same size as on any other manufacturer? ( Cat? Case? etc ) and can some one tell me what size they should be? Mine are worn, so difficult to take measurements....
Thanks for any information!!!