you talking about 727-200 i guess. break-away thrust can be up to 40%N1 i think. but taxi thrust should be less. But it depends on paving. you will require more power to taxi on gravel taxiway then for concrete.
but i really think you can try to reinstall 727.

P.S. check emergency brake lever and pressure. maybe you applied some accidentally. Also brake press indicator show only left main gear press. it doesnt show right main gear brake. if your right pedal pressed a little - you wont see it.