If you've loosened the bolt that tracks in the adjustment slot bracket, you should have enough clearance to use a hammer on the end of the adjustment slot bracket and knock it towards the engine or the front of the car. Usually the hinge pin, though snug, will not stop the bracket from moving.
See if it moves - if so - once you get it moved far enough to get a new belt on, you can place a socket with long extension on the adjustment bolt, then use a pry bar, levering on the socket from the engine to move the ticghtening bolt along the slot so the belt becomes tight. Two hands, one to hold and tighten the socket on the adjustment bolt while the other hand is on the pry bar and keeping pressure on the socket, by prying on it from the engine.
Sorry if the description sucks, try it and you'll find the right place to put the pry bar.
P.S. I think the hinge bolt is the second from the top, it's further away from the engine than the top bolt. It has a nut on the other side of the bracket - the side closest to the transaxle. The nut wants to turn when the bolt is turned - it's a bugger to get at with the axle in place - try the hammer mover first.
__________________
85 LE 2SE 500K km - died trying to push a semi off the road
95 LE 5SFE 530K km, 530K km changed engine, 549K km second engine died, now 554K Km running with a 98 5SFE block and head
01 XLE V6 310K km