The pilot reported that he had planned to fly a triangular course from Cunderdin to Cunderdin. After spending over 3.5 hours, in difficult weather conditions, to get to his first turning point the pilot elected to return direct to Cunderdin. When he arrived back at Cunderdin, the pilot spent 45 minutes in the local area before returning to land. The pilot decided to land well into the shorter of the two runways, to reduce the effort required to move the glider into a hangar however, he had forgotten that the wheel brake was not working. The aircraft touched down over half way down the 1200 metre runway. With 300 metres to run, the pilot became concerned at the slow rate of deceleration and it was at this point he remembered the unserviceable wheel brake. Although he believed it would not be necessary the pilot decided he would intentionally ground loop the aircraft, when there was 50 metres to run, if it was not slowing adequately. The aircraft's speed was still close to 20 knots, when there was 50 metres to run, and the pilot was forced to attempt a ground loop. The ground loop attempt only succeeded in altering the direction of travel and the aircraft stopped after crossing a ditch and hitting a fence. The pilot advised that he did not think to use the airbrake to slow the aircraft once it was on the runway.