hydraulic problem

hi i have a zetor 5245 with leon 590 loader my problem is loader works sometimes but has no strength with any kind of load and bucket curls up quick but falls back ive cleaned mag filter changed fluid but still does it then after a few attemps it quits working all together and pump whines .when attempting to raise loader it will go down rather than up can any one tell me whats happening please?could it be bad pump?