line up the tabs before you put the bolt in.......
slowly turn the bolt in until its finger tight while holding the top piece........
then tap the top of the spring with a mallet, you will hear and feel the difference when the tabs are lined up because the spring will compress. don't beat it to death just little taps.
once its lined up perfectly tighten the bolt down.
Simples
mmm just re read what you posted and you aint got that far yet.
sounds to me like you have at least one part of the assembly the wrong way round.