Harmonic balancer?

Your guess about air pressure is probably right. The center bolt holding the hamonic balancer to the crankshaft is normal thread. Clockwise - Tight. Counter-Clockwise - Loose. The bolt, however, is torqued to 219 ft lbs. At the factory, pretty tight. . I recently did one for a friend. The 'rotor' for the ignition mounted to it became loose and stopped the car from starting. I zipped it off with an air gun. Ingersal Rand, 1/2 drive, long shank, air hose pressure at 125 psi. No problem.