Alright, so I've got the 73 disc brake spindles on my car. I've got the drivers side caliper and pads mounted and good to go. Passenger side caliper piston won't compress enough to fit over pads and rotors. What gives? I can't see any evidence of corrosion that would have the piston seized. Do you think O'REILLYs will exchange it without giving me a hard time?

take your C clamp in there with you. they are good people at the one I frequent.

If it's a rebuilt unit, it's not surprising that it would be frozen. Some of the companies that do the rebuilds don't have the best quality control.

You also using new rotors and pads?
You might possibly have pads that are to thick to fit to fit over new rotors, due to variances in manufacturing tolerances.
Get get a sheet of 80 grit sandpaper, put it on a flat surface, like the garage floor, and sand the pads to fit.
Easy peasy.
Had to do that a few times in my life, when everything was new, calipers, pads, rotors.

Rotors and pads are ones that came off the donor car. Rotors still had good meat, and pads look like they had been replaced not long before the car was parked. I sanded on one of the pads some to get it to fit, and I've taken off about 1/8 of an inch and it still won't fit. I'll take a pad and c clamp with me just in case they want to give me a hard time. Now I've got to try to find the receipt, I hope they still have it in the system.

Well then, you shot down my theory, to holy hell.

it will be

Yeah, it's pretty annoying. I'll call them today and see if they have one in stock, which I'm sure they don't. Thank yall for the input.

On another note, I hope this can help someone. I caught hell getting the drum spindles off of my car. The top ball joints would not let go at all. I broke a fork trying to separate them. I bought one of these and had both of them off in 15 minutes:

https://www.harborfreight.com/3-4-quarter-inch-forged-ball-joint-separator-99849.html