How would the steering priority valve cause the pump to loose suction. I am asking because I haven't as of yet had to repair one and if I tear into it I would like to know what to look for. The Suction hose is not colapsing and there is no air in the hydrailic fluid. The unit has about 1500 max PSI. But what gets me is that this unit was just fine 2 weeks ago when I did a PM on it and had to move some heavy pallets with it to make room to work. Now it hasn't enough to lift much of anything like something is bypassing the control valve. I thought the steering priority valve just kept fluid moving to the steer orbital