On October 5, 1993, approximately 2130 central daylight time, a Cessna 310I, N8090M, sustained substantial damage near Southlake, Texas, following a loss of control during the landing roll. The flight instructor, the private pilot receiving instruction, and the passenger were not injured. Visual meteorological conditions prevailed for the local instructional flight. During interviews, conducted by Federal Aviation Administration inspectors, with the private pilot, who was receiving multiengine instruction, and the passenger, the following information was revealed. The airplane hit a bump in the runway and veered to the left side of the runway. The airplane hit a runway landing light and the left wing struck the hangar. The private pilot further stated that both pilots were applying right rudder and right brakes. In the enclosed Pilot/Operator report the flight instructor reported that "it appeared the brakes were not working properly." The private pilot reported, during a personal interview conducted by the investigator-in-charge and on the enclosed Pilot/Operator report, that the airplane landed to the left of the center line of runway 17. He further reported that the airplane "hit a bump on the runway and veered to the left of the runway" and into the grass. As the airplane continued the ground roll, both pilots applied full right rudder and brakes. He stated that "it felt as if the aircraft was skidding and with the full right rudder pedal and left braking, the aircraft kept rolling." He further said that he and the flight instructor did not have right braking with full right rudder. The student said that several runway lights were not working. During several telephone interviews, conducted by the investigator-in-charge, and on the enclosed passenger statement, the passenger/mechanic revealed that the left main wheel struck the runway light, the airplane went completely off the runway and onto the grass which was wet with "heavy dew." The aircraft slid until it hit a pole, subsequently impacted a hangar, and groundlooped as it came to rest. The left wing tip, fuel tank, wing spar, aileron, and right main gear were damaged. Upon examining the braking system, the mechanic stated "when I applied full right rudder and attempted to apply right brakes" the "right brake pedal contacts with the firewall preventing either pilot from braking on the right." A Federal Aviation Administration inspector examination revealed that 12 of 33 runway edge lights were inoperative. The airplane was released to the owner following the investigation.