The top tailgate hinge is tearing out of the body on my '88 samurai.
Does anyone know of a fix for this.
I know that it's the big tire causing it.

Easiest fix would probably be to weld the hinge to the body.  An alternative would be to remove the hinges and weld a bracing place to that section of the body and put the hinges back on.

Thanks Drone637
That makes sense to me. I had the body mounting plate brazed back in once. The body metal is so thin that it's hard to weld to. I Think that a larger reinforceing plate welded to the outside would be a good solution. I really want to carry that spare tire. Thae rocks around here are sharp.

You might want to look at just building a rear bumper with a built on tire mount instead.  I moved mine into the back as I have a rear seat.  Another club member has his built onto the roll cage, more of a baja style.