When I was trying to remove the mount on my 97 Civic so I could remove the belt that drives the compressor, instead of the nut coming off of the end of the bolt, the bolt itself unscrewed from the engine body.



Any advice on how I can get that nut off of there without mangling the post?

 

Option 1. Soak in penetrating oil and let sit over night. Double nut the open end, put the the nut shown in the picture in a bench vice (or socket with breaker-bar) , and use a wrench on the double nut end to break the stud loose.

Option 2. Heat that bitch up, grab the rubber with a vice grip, and break the nut loose.


Are you using an impact or hand tools?

 

If this all fails, you can get a new stud, nut & washer for like $20 shipped online brand new from a online hondaparts dealer. I am assuming this is on the drivers side, the passengers side stud is a few bucks more.

I know I had a fun time removing the nut from both sides on my car when I changed the torque mounts, I ended up have to remove the entire passengers side (including the mount on the transmission) and clamp it down and use a big breaker bar to get the nut off of the stud.

 

Antiseize on the new but before torque down, will help future removal and avoid this situation.
junk yard for cheap stud and but..