Has anyone ever found a way to detect problems with cardan shaft bearings? Is there enough energy and contact to transmit cardan shaft bearing faults through to the nearest machine bearing?
Cardan (cross) shaft bearings don't rotate in the usual way, and in fact, if the joint angle is too small, will not rotate at all. Makes it hard to identify a characteristic vibration.
You can instead identify cardan shaft defects that produce increased joint motion as the bearing rollers deteriorate. Should be a twice-per-revolution motion or acceleration at the support nearest the end of the shaft.