Thanks Venomous1, I will keep that in mind but I'm good for now.
As these trucks get older and the brake seals crumble and leak, there will be more stuck plastic pistons in calipers.
Too bad the piston bore wasn't hard-chromed at the start as that would/should extend the caliper's service life considerably. But that would add cost, etc. etc.
Maybe that wouldn't work either as grit would eventually get in there I guess. Maybe just a better sealing system or material?
Hmmmmm...
Or maybe go back to drum brakes with a simple $30.00 brake cylinder actuator. We could paint the drums red and...oh, never mind...
Have fun.