I put a Hydroboost in my Wife's 75 Bronco.
Here are the bleeding steps I used when I set it up.
http://www.agrperformance.com/AGR-In...structions.pdf
It shouldn't groan. What pump are you using is it up for the task of big tires and hydro?
Let it sit a little and double check you don't have any small leaks. Start by discharging the hydro with three pedal depressions. Cycle the steering S L O W L Y a few times and recheck the reservoir level.