I've got a Hyundai Tucson 2006 Model 2.0 manual .while I was busy installing a new aircon belt the crank shaft pulley bolt came loose. Only noticed when I started the car and heard a knocking noise from the pulley. Now the bolt is hallway out and I cant get in in or out it seems to be stuck. Can the noise be from the loose pulley or is there something else behind the pulley I could have damaged ?and what could be the reason for it to be stuck halfway out?

 

Can not see it so don't really know what has happened
The bolt is all the way out?? Half way out?
Can not get it back in??
Check the threads on the bolt to make sure they are in good shape.
No good reason for bolt being loose.

If it is stuck then you will need to release the tension that is on the pulley first then try tightening.

 

This is the pulley ime talking about and the bolt is halfway out but its stuck now cant loosen it or tighten it

 

If the bolt is very tight then could it have been put in cross threaded?
Did you see this before you started to replace the AC belt?
The only other thing I can think of is the woodruff key is out of position and stuck in there.
Crank shaft bolts are usually quite difficult to remove .. when in all the way
Never saw one that is half way stuck. Sorry.