I'm assuming this is the bolt that goes through the rubber body mount. I just did mine and had the same problem. There is a metal tube the bolt goes through ( inside the rubber) and the bolt is likely rusted into the tube making it a larger diameter than the hole in the floor. This tube is also probably stuck solid into the rubber mount. I used an impact wrench (alternately tightening then loosening) to break it free. I also was replacing the floor pans so air chiseled (carefully)the spot welds from the large "washer" the bolt drops through and then had to cut the bolt off after I got it out so I could re-use the washer.


Dave
66 GMC- father /son project with the "GMC KID"
36 Chevy PU- 4x4 lifetime project
64 Skylark- wife says its hers