Hello, I have a 1928/1942 Underwood No 5 (it was apparently completely rebuilt in 1942 or so losing all its character ). My issue is with the Key Lever Lock Release button. The bell rings as the carriage nears the right margin and the carriage stops at where the margin pointer is as it should but the button does not release the carriage it just smoothly comes back out. 
If i push the bell rack frame lever to the right it will let you type more characters as it should and stop as it should when it reaches the end of the margin block. Am i missing any springs? How does the bar get pushed by the metal rod if there not close together at all? Am i just missing something obvious as I'm more electrically inclined then mechanically lol. See https://imgur.com/a/QXVbsqq.

Thanks