help removing trailing arms on a 64 impala

i cant figure out how to remove the bolt/shockstud that holds in the rear of the trailing arms on a 64. If anyone can help i would be real happy! Thanks in advance.

i did this years ago i had to stip a 64 but i think you have to spin the whole shock mount out i think its threaded in there.

thanks i guess I need a breaker bar