[GB SISSON]

NCSU, I replied to your PM but it seems it didn't send. I sold my 38 tonner 25 years ago and it's been mostly newer ford since then. If it's like the jailbar trucks, which have a similar mounting atop the tank, there are 2 straps, one each side between the seat base and the tank's surrounding 'skirt'. These are at the rear of the seat 's cushion. At the front edge of the seat base it sits on a couple of steel pegs, shaped like bullets that are attached to the tank's skirt frame. Looking at the front edge of the seat cushion from the underside there are two steel strips, maybe 1 1/4" x 3", each having 3 holes for seat's fore and aft adjustment. In other words, the bullet pegs locate the seat in your choice of three positions. You have to lift the front of the seat off the bullets and slide it forward or back. The seat back, if like the jailbar trucks has a sort of hinge on both sides at the top. Simply pull the hinge pins and lift the seat back out. I hope this helps.