As with many of the older guns like this, unless you can find a gunsmith who has experience with them you're likely going to be left with trial and error on your own. Could be the hammer spring has weakened over the years and is causing the cocking issue. Also think you're on the right track for that loose spring, though I can't help ya with getting it back where it belongs. More than likely if it was loose in the action it probably means it broke and needs replaced.