Someone may have already broken the bleeder screw off. I've bought more then one old Mopar with broken off bleeder screws. It's gotten to the point I really expect to be replacing the wheel cylinders on every used ride I buy. I usually end up replacing the brake lines as well. The line to the rear is usually crusty and ready to fail, and the two lines across the rear axle are just slightly better and often don't survive the wheel cylinder replacement. Gene