This style expansion bolt. Hold the body with vise grip while tightening the nut. Then pull it out.
http://ecx.images-amazon.com/images/I/31522oEJfvL._SY300_.jpg
(Pictures won't post this morning)
Bruce
http://ecx.images-amazon.com/images/I/31522oEJfvL._SY300_.jpg
(Pictures won't post this morning)
Bruce