One of the common designs for parking brakes is to have a drum setup inside the rotors on the rear disc brake setup. Recently while I was replacing the rear pads and rotors on a car, I found a problem with the parking brake.
All of the friction material was completely gone, off of all four shoes. I don’t know where it all went, because there was no dust inside the rotor from them wearing away, plus the metal backing of the shoes is just plain rusty, not worn down like you would expect from worn out brakes.
One possibility is that the shoe lining actually separated from the shoes entirely, but even if that happened, where did it go? There was no dust or any evidence that it ever existed.
Mechanical Malarkey T-shirts, hats, and stickers are available to order!