The wrench you are working with does no! loosen a nut, your car sometimes succeed by slipping a length of pipe over the end of the wrench and pushing at the end of the pipe. why does this work? the pipe effectively lengthens the wrench. you can exert the same force to the end of the pipe, and get a greater torque became of the longer lever arm. the pipe effectively applies extra torque duo to elastic force of its deformation. this extra torque you to loosen the nut. the pipe effectively decreases the torque that holds the nut. you need to apply less torque to loosen it, so you can succeed by applying the same farce as before.