Dynamic rotate and chain stretch

[coffeejeanpaul]

Good day. 

I am looking to replicate the action show in the attached short video. 

I am trying to rotate the crane and let the hydraulic pistons follow. 

When I make it the piston some times follow but just rotates and does not extend. 

I am not able to figure it out of the bat what I am missing. 

I would greatly appreciate any tips

[j.palmeL29YX]

I'd do it using parametric constraints. 

[Libbya · Accepted solution]

You got it almost correct, but made two significant mistakes with the polar stretch action.  First, you associated the action with the wrong point of the polar parameter.  Second, you added the bottom of the hydraulic cylinder to the selection set for stretching instead of the selection set for rotate only.  Correct those two mistakes and it will work fine.  

[coffeejeanpaul]

Thank you boss, wanted to do the same but want to avoid using constrains. 

[coffeejeanpaul]

Thank you so much , took me a min to figure out, Key point Read the prompts before blindly selecting items.