what about a air pullback release, no pad to disk contract at release, the pinion brake would be used as a Ebrake only (more for holding at a standstill), no air pressure, it applies, the standard ebrake leaves a lot to be desired, the brake would set eather by dumping the air from a valve on the dash, no air at startup, or a broken air line, the standard 5t ebrake just about holds the truck, let a lone a emergency stop. ive seen a bunch of newer big trucks as well as heavy equipment that use a disk brake setup as the ebrake, some of these you can not power though