What size are the bolts that hold the cab to the frame? I busted one off when I tried to remove it. The head is a 13 mm. The bolts look like they have been buried in the ground for a hundred yrs. Threads are gone and almost rusted completely through.

I also have to get the busted off bolt out of the boot. Can I lift the cab just enought to remove the upper boot? How does that upper boot come off?