HOW TO CHECK INTERNAL BOOM CYLINDER LEAKAGE HOW TO CHECK INTERNAL BOOM CYLINDER LEAKAGE 1. Lower the bucket teeth to the ground with bucket cylinder fully retracted and arm cylinder rod retracted almost in full. 2. Disconnect hose (A) from rod side of boom cylinder and drain oil from cylinder and hose. (put cups on piping and hose ends) A 3. Raise bucket OFF the ground by retracting the arm cylinder rod. If oil leaks from piping side and boom cylinder rod is retracted there is an internal leak in the cylinder. If no oil leaks from piping side and boom cylinder rod is retracted, there is an internal leak in the control valve. 5-22