What was found
THE LEFT AND RIGHT MAIN LANDING GEAR WHEEL BRAKES WERE REPLACED WITH OVERHAULED UNITS AND THE AIRCRAFT WAS RELEASED TO SERVICE ON 2/26/2020. THE AIRCRAFT OWNER/OPERATOR FLEW ON MARCH 1 2020 AND REPORTED AFTER THE SECOND LANDING INTO KDAL LOVE FIELD THAT THE LEFT AND RIGHT BRAKES HAD FAILED. MESSAGE ON PFD SHOWED BRAKE FAILURE WITH NO BRAKE ACTION. EMERGENCY BRAKE WAS INCORPORATED WITH NO INCIDENT, AIRCRAFT WAS TOWED TO HANGAR PARKING. SUBSEQUENT MAINTENANCE FOUND THE BRAKE SYSTEM TO HAVE AIR PRESENT IN THE SYSTEM, THIS CAUSED A MESSAGE TO BE DISPLAYED ON THE COCKPIT PFD "BRAKE FAILURE", AFTER BLEEDING THE AIR OUT OF THE SYSTEM THE MECHANIC PERFORMED AN EXTENSIVE TAXI TEST ON THE BRAKES WITH NO ADVERSE CONDITIONS NOTED.