Stuck front caliper question

[BulletHead]

I was trying to replace the front brakes when the following occurred.

I took out a pad out of one side and was pushing the pistons back in one by one, when the unattended piston pushed out fully and now this piston's stuck in the full out position and it wont go back in. I've tried pushing it pretty hard, no avail.
Is it seized? How can it seize like that? Or is it even seized?
I also tried loosening up the brake fluid bleeder, but that didn't help any.

Anyone have any ideas as to what I can do without replacing the caliper? The truck is rust free, so I dont think rust is a factor.

 

[gotmud]

I would try blowing the pistons out of the caliper with compressed air and checking for corrosion. Now is a good time to inspect and/or replace the seals anyways since you are doing a brake service. I assume you are resurfacing the rotors as well?

Brake fluid absorbs moisture. So while the outside of your truck might be rust-free, there could be plenty of moisture/corrosion in your brake lines. This is especially true if the fluid hasn't been serviced.

 

[samibattlemaiden]

This is the cruiser gods telling you to do the runner upgrade

 

[Medic83]

This just happened to me last night. What did you do? Last year, my other side was stuck as well but it was two pisons on the same side. I just replaced the caliper, but im wondering if I can save this one.