wheelnuts

Hi,

Is it possible that (in earlier years) they used 4 wheelnuts with on thread and 1 with an opposite thread on 1 wheel?

I don't know how they call that in English but is it left- and right thread?

yes it is left and right hand threads. Maybe one was broken and replaced with one of opposite threads

That is usually the case. Something was replaced/repaired (usually on the left hand thread side) and replaced with right hand threads. Granted, you could be experiencing just the opposite.

On one wheel no. It would be all left hand threads on one side and right and on the other.