Abstract: An excavating and loading system is disclosed which includes a vehicle with an excavating wheel assembly at the front. This wheel assembly includes plural excavating wheels each comprising a plurality of digging buckets having a wall supported for pivotal movement between a material receiving position and a material dumping position. A spring is connected to each movable wall for normally positioning the wall in the material receiving position. A cam mounted on each movable wall is engaged by a mechanism fixedly supported at a point offset from the rotational axis of the excavating wheel to pivot each movable wall to the material dumping position against the action of the spring associated therewith.