Parking brake mileage
 

1999 ML 320, 255,000 miles-replace factory pads in back.
As long as I was doing the back pads, I thought I should replace the ineffective parking brake shoes. The technical literature is full of warnings about the automatic slack take up in the actuating cable (just crawl under the truck, lower the muffler and figure out the Rube Goldberg device), so I replaced the shoes with the brakes on. Pulled the drums, pushed the pedal down, disassembled, installed bottom shoe, donned safety glasses, engaged springs, and pried the upper shoe into position. Aligned with a ball peen, slowly released pedal confirming shoes were engaged and taking up slack, and that was it. No anti-slack concerns.
Shoes in both drums had debonded with linings floating loose to jamb up and increase rolling resistance. Think I got 1.5 mpg out of this.