[spdbrake]

If your Bendix is stuck (starter gear always engaged to the flywheel) it would explain bumping the car in gear to fix the issue. If so... The starter brushes are probably shot from running all time against the commutator. Typ elec motors (and starters) with a flat spot in the commutator have to be bumped with a hammer or rotated slightly to get them to work again. Can be very random in natures as it depends on the stopping point of the motor.