How hard is it to replace a brake booster on a 2005 Ford Escape?

it's not that hard as long as you are careful.

inside the cabin under the dash remove the clip that holds the booster push rod on to the pedal shaft. then remove the 4 nuts holding the booster, 1/2 inch or 13 mm nuts. use a deep socket.

open the hood and remove the master cylinder from the booster, 2 1/2 inch or 13 mm nuts hold it on and you will have to use a wrench. pull the master cylinder away from the booster, but be very careful not to damage the brake lines. you should be able to remove the booster and maneuver it out past the master cylinder. install the new booster in the reverse order.