update:
OK, the wheels are back on now, after cleaning the drums thorughly (and painted black from the outside, instead of the ugly rust...). The hand brake seems to work fine to me now: lever pulled up - rear wheels blocked fine, lever down - wheels are rotated with the hand without problems.
took the car for a test ride - unfortunately the rumbling noise is still there. At least I know that the rear breaks are not seized.

Here is a strange thing I noticed while reinstalling the drums: the drums are of course totally rusted, and when rotating the wheel by hand there is a definite noise coming from them: a metal touching metal noise. So, I looked and noticed that the drum cover is actually touching the "base plate" (where the brakes are sitting on), and when rotated they actually screech - again metal on metal. Both sides do that, but the right hand side more.
So, I took them off again, and tried sanding a bit the rims of the drum - was not so succesfull, but I guess better than nothing.
now, I loosened a bit the two phillips crews that close the drum, so there is less contact between the 2 parts, and then it screchees less, but I do not think this is the way to go, right? I guess these screws need to be closed tight, right?In any case, when the wheel is back on, the drum is tight any how, right?

So, is it possible that my rumbling noise comes from this stupid metal contact? if so, what should I do in order to cancel this contact between these 2 parts?

thanks for your advice and help!

chkto1000 said:

Here is a strange thing I noticed while reinstalling the drums: the drums are of course totally rusted, and when rotating the wheel by hand there is a definite noise coming from them: a metal touching metal noise. So, I looked and noticed that the drum cover is actually touching the "base plate" (where the brakes are sitting on), and when rotated they actually screech - again metal on metal.

Click to expand...

It's pretty common to get this contact between the splash shield on the back plate and the drum.
I've highlighted the dragging marks in this picture.

chkto1000 said:

So, is it possible that my rumbling noise comes from this stupid metal contact?

Click to expand...

No this contact makes a sh-sh-sh noise as you drive along. The rumbling is from the propshaft area.

chkto1000 said:

what should I do in order to cancel this contact between these 2 parts?

Click to expand...

You simply remove the complete splash shield, like in this picture.

Nodge68 said:

It's pretty common to get this contact between the splash shield on the back plate and the drum.
I've highlighted the dragging marks in this picture.
View attachment 192476

No this contact makes a sh-sh-sh noise as you drive along. The rumbling is from the propshaft area.

You simply remove the complete splash shield, like in this picture. View attachment 192477

Click to expand...

Sorry, I do not understand: what should I remove here? or is this a joke? It looks like the drum is not there...

chkto1000 said:

Sorry, I do not understand: what should I remove here? or is this a joke? It looks like the drum is not there...

Click to expand...

The drum is removed. That's the back plate. There should be an inner ring of thin metal all round the outside, like in the picture above. This thin ring of metal rusts and disintegrates, causing the rubbing sound. The way to stop the noise, is to completely remove the thin ring. I don't have a better picture at the moment, but it's pretty obvious what the noise is, when the drum has been removed.

Nodge68 said:

The drum is removed. That's the back plate. There should be an inner ring of thin metal all round the outside, like in the picture above. This thin ring of metal rusts and disintegrates, causing the rubbing sound. The way to stop the noise, is to completely remove the thin ring. I don't have a better picture at the moment, but it's pretty obvious what the noise is, when the drum has been removed.

Click to expand...

ok - now I understand. Thanks for the explanation.
you spoke about noise from the prop shaft: what do you think can be the reason for that? what should I do to in order to check?

You want to check the bearings on the VCU, and the mass damper for splitting of the rubber too. Also check the propshaft universal joints.

It's best to simply remove the whole propshaft assembly, so it can be eliminated or proven to be the cause.

Nodge68 said:

You want to check the bearings on the VCU, and the mass damper for splitting of the rubber too. Also check the propshaft universal joints.

It's best to simply remove the whole propshaft assembly, so it can be eliminated or proven to be the cause.

Click to expand...

All right, will do. Thanks again.