Question How many air storage tanks are used in an air brake system? Answers Two tanks Four tanks Six tanks The number varies. Explanation Air storage tanks are used to hold compressed air. The number and size of air tanks in an air brake system varies among vehicles. Take a FREE Practice Test Now This questions appears in the following tests: North Carolina Knowledge Test Class A , Pennsylvania Knowledge Test Class B , South Carolina Knowledge Test Class B , Texas Knowledge Test Class B , Colorado Double , Mississippi Passenger , Delaware Air Brakes , Florida Air Brakes , North Dakota Air Brakes , West Virginia Air Brakes ,