86 sr5 rear brake drum removal

I have a 1986 Toyota SR5 2wd with 4 cylinder 5 speed and 190,000 miles. The wheel studs broke off the rear axle and I can't get the drum off. The drum and axle turn just fine and their are no funny noises or hard spots. Pretty sure I have to back off the shoes but can't figure out how its done. There is a slot at the top of the backing plate similar to what is found on the bottom of American cars for backing off the adjuster but it doen't appear to be for that purpose. What's the trick? Don't want to break anything.