Belt Tensioner

I have a 89 2.8 V6 with a power steering fluid leak. Im trying to get the belt off but see no way of getting a breaker bar in to loosen it. The only way that I can see of getting too it is by jacking up the car and going in from underneath. ( Doesnt make much sense to me?) Ive got about a thumbs width if not less to work with. If you have any clue on how to get the belt off please reply.

we used a combo wrench open end box wrench...just slide it on there and go