Hi,

I have this sound coming from rear brakes when applying brake.
It is the same sound and frequency as in this video.
It is more clearly audible at the end of braking as in video.
https://www.youtube.com/watch?v=PC_QFJy2sLw
If I jack up rear and spin the tires, no sound at all.
What could it be?

Sounds like the noise coming from some small part moving rather than the noise from the shoe slipping against the drum. Is the drum round or worn out causing the shoe to move against the back plate?

Another possibility is the brake shoe normally rubs against the back plate in several places and it slides against the piston and the fitting at the bottom end of the back plate. Those parts should be lubricated with a high temperature brake grease

I have aluminum wheels and wheel bolts threaded part is 28mm long.
Can they be too long and rub something inside drum?

jte said:

I have aluminum wheels and wheel bolts threaded part is 28mm long.
Can they be too long and rub something inside drum?

Click to expand...

Yes..

Just remove one bolt.. and check the end for 'polishing'

Problem solved.
It was rust built up in backing plate and brake drum.
They came in contact while braking.

jte said:

Problem solved.
It was rust built up in backing plate and brake drum.
They came in contact while braking.

Click to expand...

However it is also true that the shoe and the back plate normally come in contact. The points where they contact should be lubricated with a high temperature grease. I use copper paste. At least it stops it rusting.

I have also put a very liquidy mixture of dinitro high penetrating wax and ditro black underseal on the brake drum and here and there on the back plate. I have ABS and so far in a year of use I have not had problems with it melting off. I did the same for the front calipers and the brake disks stone guard. No worries so far. Rust free is a good look!