Again 356 steaming - rubbing hub cap ?

[Atlantic07]

I am posting this second thread, 'cause I am getting really confused with the problem I have:

The right front wheel hub got very hot (as a matter of fact it was steaming).
I thought it must be the bearing. I took it apart and even removed the seal to only learn that the bearings look great (I had bad bearings before and they looked awful - you could instantly tell that they were ruined).

My breaks look good as well. One break cylinder is leaking a tiny bit though.

BUT what I noticed (after breaking the seal - dummy!) is a groove running in the hub (see pic)!!!
To me that indicates that one of the break shoes must touch the hub. The hub seems to run freely when it is on - so maybe the heat caused by breaking extents the material and it starts rubbing?

That can only indicate that something is wrong here - maybe the wrong bearing - not thick enough to ensure the right clearance? Or is there some sort of spacer missing?

ANY IDEAS PLEASE! THX A LOT !!!