Electric Vehicle Forums - Brake caliper piston stuck

Ok so I may be in Over my head. I have a 2006 Ford Escape Hybrid.
The other day I noticed a clicking noise from the front right tire when turning/ braking. Upon inspection I saw that one of the wheel lugs has broken off. I jacked it up and removed the tire / wheel. (a second wheel lug broke during this process). I figured out that I would need to remove the brake caliper and rotor to get the broken stud out of the hub. Done. I purchased two new studs and lug nuts at the auto store and After replacing the studs I ready to put everything back together. That is when I attempted to back the caliper piston up with a C clamp but it would not go. Then I realized that the Hybrid has a regenerating brake system that pressurizes every so often and you are suppose to disconnect the battery before working on the front brakes. I have successfully done this when replacing the brake pads in the past, with no issue in baking the piston up to replace on the rotor. I have tried releasing the pressure by opening the brake fluid reservoir cap and bleeding the fluid via the bleeding valve on the caliper, nothing works. I now have read you need a special scan tool to properly bleed the brakes! I also have tried to put the vehicle in "safe mode" by stepping on the brake and turning on and off 3 times, never seamed to get that right, that's why I just disconnected the battery when I replaces pads.
Is there anything I can do at this point to back the piston up so I can put everything back together? at this point I can't even drive it to the dealer. please help.