[dlkj07]

I think you’ll find the pin pushes out through the hole with the large cap.  Mine pushed out using my thumb and a brass pin.  Latitude28’s post is pretty complete and gives part numbers and suppliers.  
Several gurus have rebuilt them.  Oddly, I rebuilt just one and two weeks later the other lock failed.  Lesson: do both !!

First thing I did was try and push the pin out through the top, wouldn't budge. Like I mentioned above, my lock pin is a little different design than Latitude 28's...it appears to be threaded in and need some type of spanner wrench to get out...I think.

I'm also thinking about rebuilding the other top lock, even though it's dry as a bone and is working fine.