Regarding dynamo bearings. Firstly the main bearing, when sitting in its housing sits about 020" proud of the housing then it is held tight with the bearing clamp held over it by three small countersunk BA screws. After time and vibration the bearing clamp doesn't grip the bearing any more so I usually skim the back of the clamp by a few thou to make sure it presses on the outer race of the bearing. The commutator end bearing is not supposed to be tight in its housing or it will get destroyed when fitting it as it is quite flimsy and preload on this bearing will cause it to overheat and collapse when put into use. Provided the outer race shows no tendency to turn it is probably OK. I test dynamos on a small rig and check that the bearing hasn't turned after a few minutes on the rig. Using Loctite or similar is OK provided it doesn't set too quickly as you don't want it setting before the through-bolts are tightened.
