Brake caliper piston backing out

Changing brake pads and rotors: should be an easy as pie job. Nope, not for me; it has me on the verge of throwing hammers.

After an hour and a half spent unfreezing a caliper slide pin (and me realizing that the frozen pin was to blame), the second rear caliper is giving me trouble as well.

I have one of those caliber cubes, with the different keyed edges to match different makes of brake caliper pistons. It worked fine on the right side , but on the left, I had marginal success. I then reversed the direction to see if it was reverse threaded, and here's how it looks now:

Am I SOL trying to get this back in? The boot has come out all crinkly. I have been fighting it for 45 minutes now, and it does not appear to be moving. And my brake fluid reservoir cap is open in the process. What's my next step?

You need to squirt a little WD40 or similar on the boot to keep it from winding up, then grab a big set of channellocks and sqeeze a bit while rotating. The proper tool has a push/turn action to it. You may need a third hand to do it properly. If the piston rotates, its nor seized up.

I've found that if I remove the rotor and mount the caliper back on the bracket it makes it much easier to push and turn the piston then when it's loose on the floor etc.

Thanks for the help and reassurance. I finally got the piston depressed enough to cover the brake pads. One of those glorious days where I get about 1/4 the projected work done.