My AVL just rolled over 7000 miles and I'd like to figure out if my rear drum brake is nearing the end of its life. Is there a way to tell how far its worn down/ how much pad is left?
I also was wondering about the same thing and took apart the rear wheel drum on my G5, which is UCE not AVL but I think their brakes are similar for all practical purposes. To my surprise there was a lot of pad left on the shoe even after 27,000 miles on them
(picture). Their braking power however was way less. There were 2 reasons - drum needed good cleaning and secondly the pads got oily over the 4 years I had used them ! So I put in new pair and the whole thing feels like new.
In my case these pads lasted way more than expected, perhaps due to the fact that I did not use rear brake alone or very heavily. I used both brakes - more of the front brake than rear. Now I have started to use rear brake more than before, after seeing that they lasted so well.
The pad thickness is not the only indicator of its braking power, though you do not want it completely gone and scouring the drum.
But before that happens, the brakes do not stop the bike quickly due to other reasons. If that is happening (even after tightening the brake rod nut), it is time to open and clean the drum. If needed, replace shoes.