As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
PILOT REPORTED POPPING NOISE COMING FROM LEFT MAIN GEAR WHEN BRAKES WERE APPLIED. BOLT AND BOLT HOLE IN THE LANDING GEAR SPRING ASSEMBLE WAS FOUND TO BE WORN BEYOND LIMITS. AIRCRAFT HAS BEEN USED AS A FLIGHT SCHOOL AIRCRAFT SINCE NEW. CAUSE IS NOT KNOWN AT THIS TIME. PART WAS RETURNED TO MANFACTURER FOR EVALUATION.