My 2005 Mercury mountaineer will not come out of park it was not doing that yesterday

Hello, first - it's important to note you selected "E-150" as the model instead of Mercury Mountaineer. However, it's also important to note that the concern is not unique to any vehicle - it could happen to any vehicle, so I will answer here anyway. The brake caliper replacement and shift lever not coming out of park are two distinctly separate situations and have no apparent correlation to each other. However, Ford products over the years seem to have concerns around the function and operation of the brake lights switch at the brake pedal, as well as the wiring connector to the switch. Check to see if it's connected. Check the operation of the switch. Replace as needed. Check the wiring harness for damaged or melted terminals. Replace as needed. Note also that the only thing I can think of that could possibly correlate is if during the brake bleeding process something got dislodged or damaged from pumping the brake pedal. Good luck!