Cab Support spot welds

[71c10longbed]

I am replacing the front cab support (passenger side) on my 71. For the life of me, I can't find the spot welds. I have used an abrasive pad to cleanup the flange of the cab support and still can't find them. I did the drivers side a year ago and had no problem. Any ideas how to find these elusive spot welds? My air hammer won't do much unless I cut those welds out.

[GASoline71]

I went through the floor, when I did some work on the cab of my truck. After I pulled the rubber mat and jute from the cab and then hit the floor with a stiff wire wheel, they were pretty easy to find.

Gary