So I just installed a replacement caliper. Went to set the pad clearance and I can't get the piston to move. The adjuster has no effect on the piston. The screw just spins with no effect. Can anybody offer any insight?

Don't have personal experience, but Eric Shea had a lengthy posting about R&R of the rears, if my memory serves me right.

Eric also has a link on his website about rebuilding that may offer some insights:
http://www.pmbperformance.com/page/page/1925687.htm

Hope this somehow helps.

-- brett

The "replacement" caliper is in what condition? If it has been properly rebuilt, then the piston should move as you turn the adjuster. It sounds like the adjuster and the piston are not linked. The adjuster and piston are supposed to be linked by a friction ring on the body of the adjuster that sits in a groove in the piston. When it is out of position, I rotate the adjuster in the opposite direction until I hear it SNAP into place. If the piston is seized in the bore, you can pull the ring out of the groove easily enough. If the friction ring is too well lubricated, it can just spin in the groove; this is a pretty bad situation. Basically, the piston must move freely enough for the adjuster to work properly.