BLEEDING A POWER STEERING SYSTEM.- Any time you replace or repair a hydraulic component (pump. hoses, and power piston), you should bleed the system. Bleeding the system assures that all of the air is out of the hoses, the pump, and the gearbox. Air can cause the power steering system to make a BUZZING sound. The sound will occur as the steering wheel is turned right or left.

To bleed out any air, start the engine and turn the steering wheel fully from side to side. Keep checking the fluid and add as needed. This will force the air into the reservoir and out of the system.

Check this link out:  http://www.automedia.com/Bleeding_Power_Steering/ccr20071101bs/1

Kenny,  I put new hoses on our '78 pace car last spring.  Take your time and it will go ok.  Each hose is unique as to location.  Use care in starting threads as surface on end of power steering cylinder  is not square cut.

No, it won't affect the valve.   Filling it by starting the engine is a bit of a problem due to the fact that you will whip the air into the fluid.   It is better to fill the pump, disable the ignition, and crank the engine a little bit. Refill the res, and repeat the process.  It will fill quickly and won't create a lot of air.  Then start it, turn the wheel back and forth, and refill.