Tractor Repair: 3 pt hitch, power models, model tractor

Question
I have a White 1270 utility tractor on the farm and the 3pt hitch has quit operating, it will not lift anymore.  I have taken apart the supply pump, it is aluminum and to me seamed pretty scored, i have also taken apart the hitvh operating valve and cleaned it, and chaned the oil in the system.  when i put the pump and the valve back together and on the unit , when i started the tractor the hitch came up but would not go down i stood on it to put weight on it and now it will not go up.  I noticed that the oil taked a long time to reach the control valve, even at full rpm.  what else can i try to correct this problem ?  

Answer
Chris I am not real conversant with your model tractor as  in Australia we only get a couple of models in the White tractor range mostly big horse power models.
Chris I suggest you look at doing a pressure test on the system and a flow test on the pump as you said the oil takes a long while to come through.
This suggests that the pump could be worn out as you indicatted that there are score marks in the pump body.
This is the best thing I feel check it out and let me know how you go.


            Regards Danny Last