Brake caliper help badly needed

[Normanator]

Afternoon all, have been having an issue with our recently purchased rig where the pedal has to be pumped to work in a decent fashion. Figured it was air, went to bleed and found the fluid was red/black... got to flushing all that out. On the rear I noticed the caliper piston is a solid 1/8th inch off the pads...
Took it off to "unscrew" the piston figuring someone over tightened it last brake job. Problem is, if I back it off one half turn to line up the notch for the little nub on the pads, it is too far out to fit back on! Pads are near new, and it has always been my understanding that caliper pistons should back off only 4 or 5 thousandths when the brake is released, not anything like these are.
I have attempted to set/unset the parking brake several dozen times as well, but even fully down/on, the piston does not touch the pads...
Any help or advice on how to fix this is greatly appreciated!

 

[mguy13sport]

That piston may be seized. Are you using the special disc with 2 notches on it to turn/depress the piston?

 

[ProjectSHO89]

Replace the caliper (and the rubber hose, while you're at it).

 

[Normanator]

I have the appropriate tool yes, and I just picked up new hardware to swap, so hopefully it's just a piston issue!

 

[Normanator]

Once the offending drivers side caliper was off and compared to new one it was quickly apparent that someone had adjusted the piston out to near max when installing new pads last, likely because it wasn't working. Passenger side pads were down to about 75% vs almost 100% new on drivers. I'm guessing they wore down simply from drag until they no longer were putting pressure on the piston and just floating. Whole piston was a rusted mess.
Swapped both sides for the heck of it plus the rubber lines, flushed the whole system so now it no longer looks full of ATF, and it all seems to be functioning.
Most annoying thing is this came from a Ford certified dealer and the paperwork says THEY changed the brake pads as part of the re-cert service 2 months ago, so they will definitely be getting a call tomorrow about it...
I appreciate the help given, it confirmed what I figured and saved headache messing with it!

 

[peterk9]

I have the appropriate tool yes, and I just picked up new hardware to swap, so hopefully it's just a piston issue!

Welcome to the Forum Norm.

Peter