A device for repairing a pipe internally includes a body and a drill assembly mounted on the body. The drill assembly has upper and lower arms, pivotable between a closed position in which the arms occupy a radial area not substantially greater than a diameter of the body and an open position in which the arms bear against substantially opposing points of the pipe wall to stabilize the drill assembly within the pipe. In the preferred embodiment for repairing pipe joints a hydraulic drill head bears against the pipe wall when the arms are in the open position and drills a hole for a sealant nozzle mechanism mounted on the upper arm, which swings into position in front of the drill head to inject a sealant into the pipe joint through the drill hole and seal the joint.