dryer would heat up once on a full hour cycle

i took a stab that it was the thermostat,but it wasn't.after finding out it was the coils i purchased them and lifted the top of the dryer and undid two screws in the upper front of the dryer and lifted the front off all while holding the tub in place.The coils are located in the very front left of the dryer,i took the holder bracket off,disconnected the wires and replaced the coils(they just sit on a rod)dryer works like new and thanks to the new thermostat also gets hotter,i'm guessing that was next.