Well, I just replaced the rear drums on my car with used ones. The old ones were worse than I thought.
This is the driver's side. I estimate it has about 130,000 miles on it (donor car had 41k and I put on another 90k). The ridge is pronounced, and I suspect this one is out-of-spec.
This is the passenger side. As I expected, this side was worse than the other. I believe this drum has a full 175,000 miles on it. The ridge is quite deep, and this drum is clearly out-of-spec and worn out.
When I did the shoes the first time at 83k the drums just slipped off with the parking brake released and the hub nut removed. I didn't have to mess with the parking brake adjustment or disengage the adjuster through the access port in the backing plate. There was no ridge on the inside friction surface of the drum at the time. When the car was new, it took about 7-8 clicks to engage the parking brake fully. When the shoes were worn out completely, I could pull the parking brake handle up 10-12 clicks and the brakes would not hold. Once I replaced the shoes and one drum (which I allowed to get metal-to-metal), all was well and the parking brake handle would fully engage the brakes in 7-8 clicks.
But when I replaced the shoes the last time at 173k, I noticed that the parking brake handle still wanted to go up 10-12 clicks before engaging the parking brake. This was my first clue that the drums were worn past their service limits. I had seen the ridges, but had not replaced the drums. To get around this I took out the center console and adjusted the parking brake cable to make the parking brake engage fully at 7-8 clicks. But I knew the drums needed to be replaced, so I was on the lookout for replacements.
When I went to remove the rear drums tonight to replace them, I could not get them off without fiddling with the adjuster release. I had to dig around with a screwdriver through the tiny hole in the backing plate before finally getting them to disengage enough for me to pull the drums off. Removal would have been IMPOSSIBLE without the release mechanism and this access port. Mitsubishi's diagram says to simply go straight in from the back to release the adjuster, but this is comical since there are brake lines, brackets, wires, etc in the way. I was finally able to do it, but it was literally blind luck.
Once I got the new drums on and the hub nuts tightened I tried the parking brake. It was fully engaged in 3-4 clicks, which makes sense since I adjusted the cable when I replaced the shoes to compensate for the worn drums. The rear brakes did not seem to drag on my test drive, so I see no reason to remove the console again to adjust the parking brake cable back out.
It all works perfectly now. Since these were used drums of unknown mileage I was worried that I might hear bearing noise from the rear, but I didn't. If your drums get out-of-spec it can cause some issues with the parking brake, and I suspect this is why the wear limit on these drums in terms of inside diameter is only 1mm more than a new drum.