Power steering line replacement

91 4WD Jimmy,  How do you replace the high pressure power steering hose?  Can't get my hand on it where it screws in the back of the pump.  Tried from underneath, on top and pulled drivers wheel off and tried to get to it from under mud flap in wheel well.  Am i going to have to pull the pump to replace this hose.  I think I could get to it if it wasn't 4WD.  Thank you in advance for any advice.