Thanks Monkeypirate. I'll get some of that next time I'm at Home Depot or Lowe's. In the meantime I ran a rivet gun up & down the side of the barrel, set low, using a flush rivet set to impose a little impact and vibration. The rust cloud that came out of the seams and oil hole was incredible! Then I put a 7/16” open-end wrench in the vise to use as a fork to hold the lower end of the latch and set a piece of 3/4” round stock under the hook on the latch and put the rivet gun to it to expand the latch. I was able to get the latch to move fully both directions and now I'm soaking it in PB Blaster. I'll flush and lubricate it and hopefully that one will be done. This worked on the one latch that is not attached to the half track and maybe I can use a similar method to loosen the ones that are still attached. If not, I'll try the Metal Rescue or the heat method shown in the link above. Thank you guys for the help and I'll let you know how it goes.
