I got all the body mount bolts in except one. Its the one at the back of the car and the threaded insert just spins when I try to start it. I have tried by hand by ratchet and by impact and the thing keeps spinning. Any ideas would sure help because i am lost.

Thanks

sounds like the cage nut has come loose. only thing to do is cut an access hole so you can get to it. weld a new one in and weld the hole back up.

Try using a thin visegrip to hold the bolt.You can use other bolts with washers to secure them.

I finally drilled a hole in the floor and put a nut on it and cut the bolt off flush.