In the year 1970, modernizations to the conveyor was tipper-503A, who was a further development of the model 503. When you update the base car has received similar modifications and Tipper-lining was changed cabs, extended wheelbase (up to 3400 mm), disappeared behind the cabin hood. In addition, the platform length was increased. Note that Maz 503A received modernized cargo platform generic type with vertical ribs, similar to that used on the MAZ-503B, and near the end of issue used dump truck platform with horizontal ribs, which subsequently moved to the MAZ-5549.