What was found
STARTING OUR TAXI OUT FROM FBO, RELEASED PARKING BRAKE, ONCE STARTED MOVING FELT LIKE BRAKES RAPIDLY BEING APPLIED & RELEASED. TRIED TO TAXI 2 MORE TIMES, SAME RESULT. PARKING BRAKE RELEASED & NO CAS MESSAGES ILLUMINATED. SUSPECT AIR IN BRAKE LINE. TECHS NOTED SMALL BUBBLES IN TUBE WHEN BLEEDING BRAKES & FLUID NOTED DARKER THAN NORMAL. BLED FLUID CLEAN CAME OUT FROM BRAKES. SERVICED RESERVOIR. TAXI CHECKS COMPLETED, NO DEFECTS NOTED. BRAKES RESPONDED VERY SMOOTHLY. NO FURTHER DEFECTS WERE NOTED AT THIS TIME.