Pull the brake line then pull the big bolt on the right in the photo, pry the gap open a bit, and the whole assembly comes right off.
https://caltrailerworks.com/online/p...6&cat=1&page=1
Pop the whole new assembly back on, torque the big bolt, bleed the brakes, done...
eezy peezy
ps, next time let the brakes cool down a bit before dunking the trailer in the water, that should help avoid cracking in the future. Did you check the other side yet?