What an awful screeching sound it must have made when these disc brake pads wore through the pad and half-way through the metal back plate. One can only imagine. The damage that these pads wrought to the rotor and the pistons was pretty incredible, though. But, one caliper overhaul, two new pistons and seals, a new rotor, a new set of pads, and a brake bleed and this brake was just like new.
The usual 45 minutes or so to do all this (including diagnosing) was eclipsed when the pistons wouldn't budge even with a burst of compressed air through the main hydraulic line. A careful mining operation was needed to chip and finally crack the pistons in half to extract them. I sure like Avid's BB-7 disc brakes.
The left pad in this photo has had it's "pad" completely worn through and the backing plate is now 1mm thick. A new brake's back plate is 2mm thick.
(What's playing: Texas Tornados Haleys Comet)