Time for an update I guess...
Still waiting for the micrometer I ordered online... thought I'd have them home by now
Yesterday while driving the sound started again, so thought I'd try the hand brake test. Pulled the hand brake lever - sound stopped. Let the lever down - sound started. Repeated a few times, the same. So now we at least know it's in the rear somewhere.
I had bit of time today in the afternoon, so I took off the rear wheels and took a look (and a few pictures too, naturally
first four are from right rear, the rest from left rear)
Again, nothing that would be obviously loose, same amount of rust as on front brakes, only the brake pads in the back look more worn out, guess they are older. How do I actually tell if they're still good to go or if they need replacement?
The dust cover sheets look a bit bent, is that normal?
Finally, it looks like in the left rear the black plastic cover thing is rubbing against the wheel in one place - see the last picture. Do you think that might be the cause? The sound seems more metallic, not sure if a piece of plastic could do it, plus no connection to the brakes.
So if I were to service my brakes, as Biggles146 suggests, how should I actually do that? I have the service manuals for the 145/146, but I'm not sure if I could do it just by those. Is there a how-to somewhere that I could use as a guide?