The design is a heritage from the 700-series (or possibly even the the 200-series?) so it is proven! I think the idea is that the floating shoes are centered vertically when pressed against the drum and that the will stay in the same position when retracted.
Anyway, they have a tendency to bind on our V70 now and then. I have removed the shoes, greased the contact surfaces, even lubricated the wires. Everything looks fine..
I have found that if I snatch the handbrake once or twice after the car has started rolling, a "clunk" is heard from each side when the shoes jumps back fully. If I dont I suspect that they may be dragging against the drum but I dont know for sure. I have asked the workshop but they only confirm that the brakes behave like this. So it is more or less routine to snatch the handbrake first on each trip now.
It feels a bit cheap, is there any better solution? The upper return spring looks very thin, would a stronger spring help? Maybe the automatic adjustment stops working then but I could live with that and adjust manually when needed...