On August 4, 1996, at 1616 hours Pacific daylight time, a Piper PA-28-236, N8124S, collided with an airport taxiway sign after exiting runway 19L on taxiway Juliet at John Wayne Airport, Santa Ana, California. The aircraft sustained substantial damage; however, neither of the two pilots onboard were injured. The aircraft was being operated as a public-use flight by the Civil Air Patrol (CAP) when the accident occurred. The flight originated in Big Bear, California, at 1600. Visual meteorological conditions prevailed for the personal flight and no flight plan was filed. According to the pilot, the aircraft was making a full-stop landing on runway 19L. The aircraft made the approach with full flaps and a final approach airspeed of 70 knots, touching down just past the numbers. As the aircraft slowed, the pilot planned to turn off on taxiway Juliet that is located at approximately the midfield point. When he started his turn off, he applied the brakes but obtained no braking action. Seeing several other aircraft in front of him, the pilot veered off the right side of the ramp. As he was attempting to maneuver around some obstructions, the aircraft's left wing struck a taxiway sign. After the collision, the aircraft returned to parallel taxiway Charlie and was cleared to east parking at Martin Aviation. The CAP reported that there was no record of a flight plan having been filed. A postaccident inspection revealed a 12-inch-wide gash on the underside of the left wing. The gash was located between the third and fourth ribs, and extended from the leading edge aft to the aileron. The main outboard spar assembly was torn and separated. The upper wing surface was wrinkled and bowed aft of the initial point of impact. A joggle bend was noted at the midpoint of the left aileron, and the inboard edge of the left flap had impinged on the fuselage. A representative of the aircraft manufacturer estimated that, under the conditions described by the pilot, the aircraft would have required approximately 900 feet from the touchdown point to make a full stop on the runway. FAA inspectors reported they found S-shaped skid marks on the runway/taxiway at Juliet on the east side of runway 19L. The ATCT ground controller did not report any potential conflicts between taxiing aircraft and the accident aircraft at the time of the accident. The CAP aircraft manager reported that the aircraft braking system was inspected after the accident and was found to function properly. The CAP California Wing safety officer also reported that the same pilot had been involved in a similar runway excursion incident with a Cessna 206 on April 23, 1996. During that incident, the pilot lost directional control of the aircraft while landing. He attributed the loss of control to an "uncommanded turn."