Just done mine and the bolt was very tight. There was no way that it would come undone with a long extension scaffold pole and two people. Just ended up snapping three 1/2" ends clean off three different makes of tool. I found the easiest way was just to slice the bolt head off with a thin angle grinder cutting disc.maybee someone had had it off before and tightened it too much who knows.no signs of any loctite and shouldnt be !. Even with the amount of force required to re tighten(185lbs + 45 deg + 15 deg angle tighten) i myself would not be happy putting this amount of force held against the waterpump even if i was replacing it. One crack/ split casing and the crank will move round suddenly. , ! Please no offence to anyone who does it this way but not for me