The pilot reported that the airplane veered sharply to the left when he applied the brakes during the landing roll on a grass airstrip. He applied right rudder to no avail, and the airplane continued to the left where the left wing contacted a corn crop. The airplane was pulled into the corn, where it came to rest with substantial damage to both wings and the aft fuselage. The pilot reported that the airplane’s brakes operated normally prior to takeoff. The brake system consists of main landing gear hydraulic disc brakes that are operated via a mechanical brake lever located on the control stick. The airplane has a steerable nosewheel, but no differential braking. A postaccident examination of the airplane revealed that both brakes functioned when the brake lever was operated; however, the left brake responded more quickly than the right brake. The presence of air in the hydraulic lines to the right brake may have affected the brake's responsiveness, but the examination was not able to establish that the lines contained air.