ford has had recalls on the seatbelts, they just lock up like that or dont retract...mine do it too, its a ******, as far as the seat belt mechanism...you will need to take ur back seat bottom out, and i think you can get away with just laying the top down, if not thats gotta go too...there will be some push pins on the back where the seat back was, take those 3 i believe out...and take ur door seal off, and pry the plastic piece where ur seatbelt looks around near the roof off, and then you just gotta work it, its in there pretty good..but should come out..i just had to take them both out myself, putting a custom touch by putting some 6x8's in those panels, but just work it, they will come out