The body bolt "nuts" are welded inside the floor structure.If the floor pan is not real rusty, often they will come loose. If not, you have to cut the body subframe apart to replace the "nut". All 4 of the body bolts unscrewed from my 90 with an impact gun. Then it was a matter of lifting up the cab high enough to remove the old rubber mount and replacing it with the new. I suggest you loosen at least the front 2 or rear 2, and replace then as pairs, but all 4 make it better and easier. Lift the cab gently and not more then necessary, steering, brake lines, e-brake cable and fenders will all still be connected between the cab and the frame. Gene